Handbook b3 digestive system

Agastya International Foundation

The Amazing World of Food and Digestion Handbook B3

“I submit a body of facts which cannot be invalidated…..their worth will be best determined by the foundation on which they rest- the incontrovertible truth.”

-William Beaumont (1785-1853) On presenting his discovery of the working of the human digestive system.

1

Handbook – B3 The Amazing World of Food and Digestion OVERVIEW OF HANDBOOK ABL ABL1 ABL2 ABL 3 ABL 4 ABL 5

CONCEPT Learning about the food we eat

NO OF TIME in PAGE ACTIVITIES minutes NO 3 60 4

Learning what happens, in our bodies, to the food 4 we eat What have we learnt about the digestive system? 1 (Consolidation and evaluation) Some amazing facts about the digestive system 1

60

24

40

41

40

42

Feeding habits in the animal kingdom

30

47

1

Total time

3 hours and 50 minutes

ABLs WITH REFERENCE TO STANDARD SERIAL NUMBER

STANDARD

RELEVANT ABL

1

6, 7, 8

ABL 1

2

8, 9

ABL 2

3

8, 9

ABL 3

4

9

ABL 4

5

7, 8

ABL 5

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2

LIST OF FIGURES, CHARTS AND WORKSHEETS S. No

Name

Page No

Figure 1

Sample food card

6

Figure 2

Sample nutrient percentage cards

12

Figure 3

Sample chart for instructors use - food items and nutrients

13

Figure 4

Building the digestive system - 1

28

Figure 5

Structure of tooth

31

Figure 6

Building the digestive system - 2

34

Figure 7

Building the digestive system - 3

35

Figure 8

Building the digestive system - 4

42

Figure 9

Building the digestive system - 5

44

Figure 10

Inner layer of small intestine – section showing inner cavity and structure of villi

45

Figure 11

Digestion of nutrients

46

Figure 12

Glucose to Glycogen conversion

47

Figure 13

Fats in the liver

47

Figure 14

Building the digestive system - 6

48

Figure 15

Sample chart

56

Figure 16

Amoeba

63

Figure 17

Hydra

64

Figure 18

Starfish

65

Figure 19

Earthworm

65

Figure 20

Mosquito

66

Figure 21

Frog

67

Figure 22

Python

67

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3 Figure 23

Cow and Rumen

68

Figure 24

Elephant

69

Chart 1

Nutrition table 1 a

7

Chart 2

Nutrition table 1 b

7

Chart 3

Mouth and throat cavities

35

Chart 4

Food going down the esophagus because of peristalsis

36

Chart 5

Liver, pancreas and gallbladder

40

Chart 6

Summary of digestion

53

Note to Instructor: All the figures in this handbook are for the Instructor’s reference only. The Charts need to be printed and shown to the learners during the course of the activity. Worksheets need to be printed out in advance for the learners. The number of worksheets required is mentioned in the Material List.

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4

ABL 1: Learning about the food we eat Activity

Learning objective

1.1

What are the main nutrients in the food that we eat?

1.2

What are the simple ways to detect the presence of proteins, carbohydrates (starch and sugars) and fats in food?

Key messages 

Time (min)

The main nutrients in the food we eat are 20 the following: Macronutrients Proteins, Carbohydrates Fats Micronutrients Vitamins Minerals  Different foods are rich in different nutrients. It is important to have a balanced diet so that the body gets all the required nutrients in the right quantities  For good digestion, we also need to consume water and dietary fiber, the latter is also known as roughage 20  Proteins can be detected using copper sulphate solution and sodium hydroxide, the colour changes from blue to violet  Carbohydrates consist of starch, sugars and glycogen. Starch can be detected by the Iodine test (reagent colour changes from yellow to blue) and glucose (which is a sugar) can be detected using Benedict’s reagent, (reagent colour changes from bright blue to violet)  Fats can be detected by the presence of oil when substances rich in fats like sesame seeds are crushed in between folds of paper  During digestion, the macronutrients are broken down into their building blocks or smaller units. These are then reassembled in different ways for various uses in the body.

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5 1.3

How do different nutrients help us and how does their absence (or deficiency) hurt us?

 

20 Nutrients help in important functions of the body. Each nutrient has a specific function or set of functions.

Deficiencies in nutrients lead to ill health and disease. Each nutrient deficiency leads to a specific condition or set of conditions of ill health.

TOTAL TIME

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60

6 Time: 20 min

ABL 1.1 LEARNING OBJECTIVE: What are the main nutrients in the food that we eat?

ADVANCE PREPARATION Material List S.NO

Material

Required Quantity

1

Chart paper / flipchart

One per class

2

Nutrition charts, set of 2, reusable Nutrition cards, reusable (playing card size with picture and name of a food item, sample given below) Cardboard or plastic reusable boxes that can hold about 20 cards each Nutrient percentage cards

One set per class

3

4

5

Two sets of 50 cards each per class. + 10 extra cards Five boxes session, one group One set

per per

Things to do 1. Prepare food cards as per sample card given below from first set of 50 cards. Keep a set of colour pencils, marker pens and sketch pens for your own use Sample food card – Figure 1 Picture of food item

Number for nutrient on reverse Protein -1, Carbohydrate - 2, Fat/lipid -3 , Vitamin -4 (further subdivide as Vitamin A – 4a, Vitamin B – 4b etc) m

Mineral for nutrient contained; for example (1) is protein etc. For lower On the reverse of card, give numbers classes, give the learners the number code when you give out the box; (in the lower classes, learners may Namewhich of foodfood itemis rich in Min not know which nutrient, hence we tell them that 1 is the code for protein etc.); for higher classes, let them guess whether food in picture is rich in protein or carbohydrate etc. Use pictures of Mineral common food items (10 each for proteins, carbohydrates, fats, all vitamins together, all minerals together).

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2. Make nutrition charts as given below.

Two charts to be made using the information in Nutrition table 1 given below. Put Columns 1 and 2 in Chart 1 and put Columns 3 and 4 in Chart 2. Make sure that the rows are properly aligned across the two charts. Charts should have large and clear lettering. They should be reusable.

Make sure that there is enough space in the classroom to put up the nutrition charts side by side during the exercise.

Note to Instructor: All food items contain more than one nutrient; these nutrients are in different percentages in different food items. For example, milk is rich in protein as well as in calcium. Groundnuts are rich in proteins as well as fats. For this reason, you will see that in nutrition table 1, the same food items repeat as being rich in different nutrients. Similarly you will see that deficiency of two different nutrients cause the same disease condition. For example deficiency of protein and carbohydrate will lead to weight loss and weakness.

Nutrition table 1 – Chart 1 and Chart 2 Column 1 Groups. Nutrient

Column 2 Food items rich in nutrient

Column 3 Used by body for

Column 4 Deficiency leads to

Macronutrients

1

Proteins

Needed for growth and repair of body, Daals, beans, peas, building and repair soyabean of cells and tissues, Milk, eggs, fish, meat known as bodybuilding foods

2

Rice, wheat, potato, Carbohydr papaya, melon, ates sugarcane, maize, mango

3

Vegetable fats – Groundnuts, sesame (til), nuts, sunflower, coconut, mustard, soyabean oils

Fats

Provide energy for the body

Provide energy to the body, more than energy provided by equal amount of carbohydrates. Fats

Protein deficiency in children, which leads to, stunted growth and becomes a lifelong health problem. Protein deficiency over a period of time leads to a disease called Kwashikor, in which there is swelling of different parts of the body. In children, this can be seen as heavy swelling of the abdomen.

Leads to weight loss and weakness.

If the diet is deficient in both carbohydrates and proteins for a long period of time, the growth may stop completely.

Too much fat leads to overweight or obesity which over a period of time can lead to heart attacks

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8 Animal fats – Meat, fish, ghee milk, butter, cream

give us 9 calories per gram energy as compared to 4 calories per gram from carbs and proteins.

Fats are important for absorption of fatsoluble vitamins, some fatty acids (unit of fats) come only from the diet and are needed for every cell in the body.

Micronutrients 4 Vitamins Vitamin A

Milk, carrots, fish oil

Vitamin B, actually group of vitamins called B Green leafy Complex vegetables, beans, (B1, B2, sprouted daals B3, B6, and B12Pantot henic acid, Folic acid.

Vitamin C

Vitamin D

Vitamin E

Lemon (Nimbu), Gooseberry (amla), orange, tomato, guava Milk, butter, eggs, fish and liver. Our bodies prepare Vit D in the presence of sunlight Sunflower seeds, almonds, spinach, papaya

Keeps eyes and skin healthy

Poor vision, loss of vision in darkness (night), sometimes complete loss of vision

Keeps general health good and muscles healthy

Beriberi, pellagra, pernicious anemia; (see Instructor Note 4 below this table) Weak muscles and very little energy to work. Folic acid deficiency causes a form of anemia especially in pregnant women. This can be prevented by giving pregnant women iron and folic acid supplements. You may have seen this information in TV health advertisements.

Helps the body fight infections

Scurvy, bleeding gums, wounds take longer time to heal

Helps body to absorb calcium needed for healthy bones and teeth Protect skin from UV light, helps cells communicate

Rickets - Bones of children become soft and bent

Problems with liver and reproductive system

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Vitamin K 5

Tulsi, coriander, spring onions, cabbage, cucumber

effectively, prevents cell damage from free radicals Important for proper blood Problems in blood clotting clotting

Minerals

Iodine

Phosphor us

Calcium

Iron

Seafood and salt water fish, seaweed, and iodized salt.

Good vegetable sources, if they are grown in iodine-rich soil are garlic, soybeans, spinach and turnip greens.

Milk, bananas, beans, almonds (badam), cashews, cheese, egg, chicken, garlic Milk, cheese and yoghurt, eggs small fresh or dried fishes with the bones and fish sauces containing the fish bones; white beans; tofu (soybean); almonds and sesame seeds.

Green leafy vegetables, apples, pears, beans, soybeans and tofu, dried fruits. Red meat, liver, fish, eggs, chicken.

Iodine is necessary for the body to make the thyroid hormone which regulates many body systems,

Important for keeping the bones healthy Needed for healthy bones and teeth; Calcium is essential for healthy bone growth and for nerve and muscle functions; it may protect against high blood pressure.

Calcium is the most abundant mineral in the body Iron is needed in the blood and muscles as part of the system that carries oxygen throughout the body to be used for energy production in the cells.

Goiter -Glands in the neck appear swollen, mental disability in children

Joint pain and stiffness, low energy

Bone and tooth decay Weak bones, tooth decay

Anemia, Weakness

Note to Instructor- This information can be used to answer questions that may come up during the sessions.

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10 Note 1: Calcium Source -Some vegetables and leafy greens, such as broccoli and spinach, contain calcium, but large quantities of these foods must be eaten to ensure sufficient calcium Note 2: Iron absorption - Vitamin C can help the body’s ability to absorb iron, so eating iron-rich foods together with foods such as lemons, limes, oranges, grapefruits, tomatoes and strawberries will increase the iron we get from foods.

Other food components like tannins in teas can inhibit the absorption of iron and other minerals.

Note 3: Less than 30 % of our calorie intake per day should be fats; out of this less than 10 % should be saturated fat, which increases cholesterol and causes health problems. The other 20 % allowed should consist of unsaturated and monosaturated fats Note 4 - Information about diseases mentioned in chart Kwashikhor- The symptoms of kwashiorkor include the following - change in skin and hair color (reddishorange color), fatigue, diarrhea, loss of muscle mass, failure to grow or gain weight, edema (swelling), damaged immune system, which can lead to more frequent and severe infections Beriberi - Symptoms of beriberi include weight loss, emotional disturbances, impaired sensory perception, weakness and pain in the limbs, and periods of irregular heart rate. Edema (swelling of bodily tissues) is common Pellagra - Pellagra is classically described by "the four Ds": diarrhea, dermatitis, dementia and death Scurvy– After 1–3 months, patients develop shortness of breath and bone pain. Other symptoms include skin changes with roughness, easy bruising, gum disease, loosening of teeth, poor wound healing.

Anemia and Pernicious Anemia – Both lead to poor ability of red blood cells to carry oxygen and carbon dioxide. Anemia is caused by deficiency of iron and pernicious anemia by deficiency of Vitamin B 12 Rickets – Rickets is a softening of bones in infants and children, due to deficiency or poor metabolism of vitamin D, phosphorus or calcium Goiter - Goiter is a swelling of the neck or larynx resulting from enlargement of the thyroid gland 3. Make Nutrient percentage cards as given below From the second set of 50 cards, prepare percentage nutrition cards. Each card is made of list of nutrients and how much of the nutrient in a particular food item. (For example, one common food item may have 40% carbohydrate; another may have 25% carbohydrate).

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11

Sample Nutrient percentage cards – Figure 2

(Full set of cards are attached as appendix at the end of handbook)

Safety Precaution Not Applicable

SESSION SESSION 1 a

Link to known information/previous activity Today, we will be discussing something that is very important to us, something that we really like – Food!

Note to Instructor: In this session you will be doing three activities. The first one links the subject to daily life. Here we will be asking learners about the different types of foods that they eat and linking this information to the idea that there are different nutrients. In the second activity, we will help learners to see that there are different food items that are rich in different nutrients and that one food item contains more than one nutrient. In the third activity, learners will see how the same nutrient can be present in different percentages in different food items. At the end of the session, learners will be clear about the idea of a balanced diet.

Procedure Start with activity 1 where learners are asked what kind of food they have eaten over the past week. Then, list these food items on a chart with five columns (see sample chart below) according to whether they are rich in proteins, carbohydrates, fats, minerals and vitamins. Do not write the names of the different nutrients in the first row. After you have collected a few items in each column, ask learners why you have Agastya International Foundation. For Internal Circulation only.

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12 grouped them in five columns; see if you can get the names of nutrients from them. If not, you can tell them the names of the nutrients and then fill in the first row with the nutrient names – proteins, carbohydrates etc.

Sample chart for Instructor’s use (Food items and nutrients) – Figure 3 1 Proteins Carbohydrates Fats Vitamins 2 Dals Potato Ground Carrot nuts 3 Bean Rice Coconut Milk 4 Milk Wheat Sesame Fish oil 5 Eggs Sugarcane Meat Leafy vegetables

Minerals Milk Banana Egg Leafy vegetables

UNDERSTANDING THE ACTIVITY Leading questions 1. Why do we eat different kinds of food in each meal?

2. What are the different nutrients in our food?

Discussion and Explanation 1. We eat different kinds of food to get the different substances or nutrients that the body needs to grow and function.

2. Proteins, carbohydrates, fats, vitamins, minerals are the different nutrients that our body gets from food SESSION 1 b Link to known information/previous activity The learners know that we eat different foods because they have different nutrients. Using this as a starter, tell them that now we will play a game.

Procedure: Do activity 2 followed by activity 3before going into the discussion.

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13 1. Introduce the game – “Find the Nutrients” with learners.

2. Tell them that we will now find out what we should eat to get enough nutrition.

3. Ask the group to divide into 5 subgroups. Instead of using the numbers 1-5, let them call out “protein”, “carbohydrate”, “fat”, “minerals”, and “vitamins”. This helps them to get familiar with the scientific terms.

Then ask all “proteins” to be in one group and so on.

4. Now give out boxes with food cards in them (mix of different nutrients) Note to Instructor: For the higher classes, give only the numbers and let them guess whether the food item is rich in proteins, carbohydrate etc. This exercise will be a good refresher for them. For lower classes, you might have to tell them that 1 is the code for protein etc.

5. Each group should take 5 minutes to find out how many cards they have of each nutrient.

6. After 5 minutes, the groups should trade their cards – protein cards from all groups go to the “protein” group and so on. At the end of the trade, the fats group will have all food items rich in fats and so on.

7. Give the class 2 more minutes to end their game; in the meanwhile put up Chart 1.

8. Now ask each group to read out the cards in their boxes and tally them with the information in Chart 1.

Activity 3 Let us now play a game to see how different food items have different amounts of the same nutrient. This game should be played in as short a time as possible so that it is also an energizer.

(Note to Instructor: This game is to be played with groups of 10 with the rest of the learners observing.

Learners enjoy finding out who has more and running to take their place in the line. They have to stand in ascending order of percentage) 1. Instructor to call 10 learners. Give one nutrient percentage card to each learner from the percentage nutrient card set.

2. Ask them to stand in order of protein percentage in the nutrient percentage card that they have.

3. Once they form a line, ask each learner to say what food card they have and how much percentage of protein in it 4. Repeat the same game with another set of 10 learners for carbohydrate percentage and other nutrients 5. This will give learners an idea that different foods contain different amounts of nutrients.

UNDERSTANDING THE ACTIVITY Leading questions 1. What nutrient group or groups should we eat in larger quantities? (Referring to macronutrients) 2. What nutrient group or groups do we need in small quantities? (Referring to micronutrients) 3. Can you eat too much/too little of one nutrient? What would happen?

Discussion and explanation

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14 1. Tell them that proteins, carbohydrates and starches are needed in larger quantities and form the bulk of the food that we eat. They are called Macronutrients.

2. Ask the groups to pay special attention to the vitamins and minerals, which we consume in small amounts but which are essential for the proper functioning of the body. These are called Micronutrients.

3. Refer to the typical meals that were discussed in the beginning of the session. It is important that our meals contain some amount of all the different nutrients and in the right proportion. For example, if we think that fats give us a lot of energy and eat too much of them, we will become overweight. We must also be careful about drinking too much tea since this decreases absorption of iron even if our food contains enough iron. Too much heating and reheating, deep-frying of foods decreases the nutritive value.

KEY MESSAGES 

 

The main nutrients in the food we eat are the following: Macronutrients Proteins, Carbohydrates Fats Micronutrients Vitamins Minerals Different foods are rich in different nutrients. It is important to have a balanced diet so that the body gets all the required nutrients in the right quantities For good digestion, we also need to consume water and dietary fiber, the latter is also known as roughage

LEARNING CHECK Ask them to think about what nutrient they might not have consumed enough in their last meal and what they should consume in their next meal to make up. This can be a reflection question that learners can be asked to share with the learner next to them for 2 minutes before ending class or for the next class.

(For example, a learner may say that, s/he has not drunk milk in the last two days and so, there is a deficiency of Calcium)

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15

ABL 1.2

Time: 20 min

LEARNING OBJECTIVE: What are the simple ways to detect the presence of proteins, carbohydrates (starch and sugars) and fats in food?

ADVANCE PREPARATION Material List No. Material 1 Dilute Iodine solution for the starch test – Prepare by adding 5 drops of tincture of Iodine to half a test tube of water 2 One small raw potato for the starch test – cut it into 2 mm thick slices 3 Glucose solution - One spatula glucose dissolved in 10-15 ml water 4 Benedict’s reagent for glucose test 5 Spirit lamp, tripod stand, test tube and test tube holder, matches, wire gauze and beaker with water for hot water bath 6 5 ml milk or one crushed protein biscuit dissolved in water for the Protein test 7 Freshly prepared Copper sulphate solution (Add 10 ml water to a pinch of Copper sulphate in a test tube and shake till it dissolves) 8 Sodium hydroxide pellets 8 Groundnuts 9 Filter paper squares or circles

Quantity 5 drops of tincture of iodine and 10 ml water per session One raw potato One spatula of glucose and 15ml water 6-8 drops 3 sets per session

5 ml milk or 2 protein biscuits 5 ml

Two pellets per session* 4-6 groundnuts per session 3-4 per session

Note to Instructor: The freshly prepared Copper sulphate solution with sodium hydroxide pellets is effectively the Biuret reagent. The latter is expensive and the test requires heating. This is a simpler test for detecting proteins and does not require heating

Things to do Try out all tests in advance; make sure all reagents and solutions are of necessary concentration; do not waste chemicals and material. Label and arrange all material properly.

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16 All food items must be in liquid form. If it is a solid, make a paste or powder, transfer it to a test tube, add 10 ml of water and shake the test tube.

Make sure that as many members of the group as possible get a chance to do the experiment.

In order to save time, you can keep some water boiling in advance for the water bath, or keep boiling water in a flask.

Note to Instructor: In the table above on materials, you will have to prepare all the material for the tests in advance.

However, if time, space and learner number permit, it is interesting for the learners to do the experiment themselves – make the glucose solution, slice the potato etc.

Safety Precautions Learners must be told how to be careful with spirit lamps, matches, water baths and reagents.

They must be told to hold test tubes carefully and point them away from the face when they are being heated.

Reagents should be added drop by drop

SESSION Link to known information/previous activity You have seen that our food contains both macro and micronutrients. Now let us look at simple ways to detect the macronutrients in our food.

Procedure Divide the class into 4 groups. Give instructions and material as follows.

Starch test Give Group 1 the following items Small raw potato – 1 Small knife and cutting board Iodine solution (about 10 drops) One dropper The procedure for Group 1 is as follows – Cut the potato into slices about 2 mm thick.

Then add a drop of Iodine solution and record your observation Note to Instructor: Required observation - The potato turns blue where the iodine was added, this indicates the presence of starch Agastya International Foundation. For Internal Circulation only.

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17

Sugar test Give Group 2 the following items 1.

2.

3.

4.

Glucose solution (1 spatula in 10 ml water) Benedict’s reagent Spirit lamp, tripod stand and wire gauze, beaker with water for water bath Test tube and test tube holder

The procedure for group 2 is as follows – Add 5 - 8 drops of Benedict’s reagent slowly to the glucose solution and heat the test tube in a water bath. Ask learners to observe the changes in colour and compare these changes with colour chart given on reagent bottle. Record your observation.

Note to Instructor: Required observation: On heating the solution that was blue when the reagent was added to the glucose solution will turn yellow, then orange and then red. This indicates the presence of glucose or fructose Protein test Give Group 3 the following items 1. Solution of protein biscuit in water OR a few ml of milk OR a suspension or solution of gram flour in water (Check in advance which one of these gives the required result with the reagent available) 2. Freshly prepared Copper sulphate solution – 5 ml 3. Sodium hydroxide pellets - 1 4. Dropper 5. Test tube and test tube holder The procedure for Group 3 is as follows Add 5 ml of freshly prepared Copper sulphate solution to the protein solution and then add a small pellet of sodium hydroxide. Observe the colour change.

Record your observation Note to Instructor: Required observation: The solution, which was blue initially, turns into violet indicating the presence of protein.

Lipid test Give Group 4 the following items 1. 4-6 groundnuts 2. 2-3 squares of filter paper The procedure for Group 4 is as follows Agastya International Foundation. For Internal Circulation only.

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18 Put the groundnuts inside folded filter paper and crush gently with pestle. Record your observation on change in filter paper Note to Instructor: Required observation: An oily layer is formed on the filter paper.

Now ask the groups to share their observations, note them on a chart or board as follows.

1) Starch can be detected by the blue colour on addition of Iodine solution 2) Sugar can be detected by the change in colour of Benedict’s reagent from blue to orange and red 3) Protein can be detected by the change in colour of the Copper sulphate solution from blue to violet 4) Fats are detected by formation of an oily layer.

Pass around empty and clean milk packets with different fat content printed, note down the fat content.

Point out that one or more of these three macronutrients may be present in a food item. For example, we will get a positive result for protein, carbohydrate and lipid if we test milk. We also know that different food items contain the macronutrients in different percentages.

Remind learners about the game that they played with the nutrition percentages cards.

UNDERSTANDING THE ACTIVITY Leading questions 1. What are carbohydrates, proteins and fats made up of?

2. How are they processed or digested in the body? Why does the body need to process the nutrients?

Discussion and Explanation 1) Let us understand how proteins, carbohydrates and fats/lipids are processed in the body. During digestion, these substances are broken into simple units that can be absorbed into the blood.

Carbohydrates are a group made up of starch, sugars and glycogen. Carbohydrates, which are big molecules, are broken down into small sugars. Glucose is one such small sugar.

Proteins are chains of smaller units called amino acids. Two amino acids join to form dipeptides and five or more join to form a polypeptide. Proteins are broken down into polypeptides and then into amino acids; these are used to make new proteins, which the body uses for growth and repair.

Fats are made up of fatty acids and glycerol. Fats or lipids are broken down into fatty acids. Fatty acids are used to make cell walls. Excess fatty acids are stored in fat cells.

Excess amino acids can be converted into fatty acids and also stored in fat cells

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19 2) During the process of digestion, each of the above nutrients (protein, carbohydrates and fats) is broken down by both mechanical and chemical means. During digestion, enzymes act like scissors; they cut large molecules into smaller ones.

The smallest forms of these nutrients are the building blocks for the body, it is like the smallest piece of a building blocks set, the body can make many complex things with these simple molecules- like repair itself, grow in height etc.

We can think of the amino acids, fatty acids and simple sugars as the letters of the alphabet using which we can make different words. For example the letters, t, a, m and e can be used to make different words – mate or tame or team. Similarly amino acids can be joined in different ways to give different proteins that the body needs.

KEY MESSAGES    

Proteins can be detected using copper sulphate and sodium hydroxide, the colour changes from blue to violet Carbohydrates consist of starch, sugars and glycogen. Starch can be detected by the Iodine test (reagent colour changes from yellow to blue). Glucose (which is a sugar) can be detected using Benedict’s reagent, (reagent colour changes from bright blue to violet) Fats can be detected by the presence of oil when substances rich in fats like sesame seeds are crushed in between folds of paper During digestion, the macronutrients are broken down into their building blocks or smaller units.

These are then reassembled in different ways for various uses in the body.

LEARNING CHECK Fill in the blanks 1. Carbohydrates consist of starch, sugars and ----------- (glycogen) 2. A spirit solution should be heated only in a ------- -------- (water bath) 3. ------ ------ are the building blocks of proteins. (amino acids)

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20

Time: 20 min

ABL 1.3 LEARNING OBJECTIVE - How do different nutrients help us and how does their absence (or deficiency) hurt us?

ADVANCE PREPARATION Material List S.NO Material 1 2 3

Required Quantity

Nutrition Chart prepared in ABL 1 set per class 1.1 Nutrient cards prepared in ABL 1.1 1 set per class Cards withkey words present in 1 set for all learners column 2, 3, and 4 of the nutrient chart There should be only word in the card

Things to do Prepare the cards with names of nutrients, food items, what the body uses the nutrient for and what disease or health condition is caused by its deficiency. For example, 4 cards with the words, protein, meat, tissue growth and Kwashikor will be one set; 4 cards with the words, calcium, milk, healthy bones and teeth, weak bones, will all relate to calcium; four cards with vitamin A, carrots, good eyesight, eye problems; and so on.

The sets will have one word from each column from columns 1, 2 from chart 1 and 3, 4 from chart 2.

Separate the cards related to Proteins, carbohydrates, and fats into one set for Round 1 of the game. Keep the remaining cards related to vitamins and minerals in a separate set for Round 2 of the game.

Safety Precautions Not Applicable

SESSION Link to known information/previous activity You have learnt about macro and micronutrients and the simple ways to detect them. Now let us see how different nutrients help us and how their absence (or deficiency) hurt us by causing ill health.

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21 Procedure Now, tell learners that they will play two rounds of a memory game. Round 1 will cover the macronutrients and Round 2 will cover the micronutrients Play the game twice.

Note to Instructor: The game is played twice because it may be difficult to remember all the information at one time. Cover the rows in Charts 1 and 2 related to vitamins and minerals for Round 1 with paper. When the learners are memorizing for Round 2, cover the rows with information on proteins, carbohydrates and fats.

Round 1 The first time, tell learners to memorize only for the macronutrients and the second time for only vitamins and minerals. The first game will be about proteins, carbohydrates and fats. Hand out the flash cards for these three macronutrients.

Now have 4 corners in the room by drawing chalk circles on the floor or any other method. The 4 corners are labeled - Nutrient, Food item, Use in Body, Deficiency The learners must now choose their corners according what they have on the cards.

Now the Instructor calls out the name of the nutrient from one learner card.

Then the learners holding cards for food item use in body and deficiency related to this nutrient must come forward and form the group.

Thus, each group will consist of learners holding 4 cards with the following information 1) Name of nutrient, 2) Food item rich in it, 3) Its use in body and 4) What happens if there is a deficiency?

For example, learners who have the flash cards for “ protein”, “Soyabean”,” growth and repair of body” and “stunted growth” will form one group. Refer to the chart to show that this is one correct group Similarly, those with flash cards “potato”, carbohydrate”, “energy for body” and “weakness” will be another correct group.

The Instructor will facilitate the game until all learners are in groups.

Round 2 Now collect the flash cards given in Round 1.

Distribute the cards for vitamins and minerals. Repeat the same game for vitamins and for minerals.

Learners should first study the charts again for the information on vitamins and minerals and play the game as before.

Summarize briefly using the charts and then give the key messages.

KEY MESSAGES

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22  

Nutrients help in important functions of the body. Each nutrient has a specific function or set of functions.

Deficiencies in nutrients lead to ill health and disease. Each nutrient deficiency leads to a specific condition or set of conditions of ill health.

LEARNING CHECK The game in the previous section can be used as a learning check.

TRY IT YOURSELF 1. Look at the nutrient percentage column in packed food items like biscuit packs, cookies, pastries, soft drinks etc. and try to calculate the amount of carbohydrates, proteins, fats you are consuming other than regular meals.

2. Perform the starch test on various fruits and vegetables. For this, you need iodine, which is readily available in medical stores as “tincture.”

INTERESTING INFORMATION Athletes like marathon runners, swimmers or cyclists preparing for an event lasting about 90 minutes use a “carbohydrate-loading diet”. This helps them to increase the amount of fuel stored in the muscles to improve athletic performance.

Any physical activity you do requires carbohydrates to provide you with fuel. For most recreational activity, your body uses its existing energy stores for fuel. But when you engage in long, intense athletic events, your body needs extra energy to keep going. The purpose of carbohydrate loading is to give you the energy to complete an endurance event with less fatigue, improving your athletic performance.

REFERENCE Adapted from the following - http://www.mayoclinic.org/carbohydrate-loading/art-20048518 (accessed 18th January 2014)

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ABL 2 - LEARNING WHAT HAPPENS TO THE FOOD WE EAT IN OUR BODIES Activity

Learning objective

Key messages

Time (min)

2.1

What is digestion?



 What happens to the food in the mouth?



2.2

What happens to the food in the esophagus and stomach?

 



2.3

What is the work done by the liver, gall bladder and pancreas?







Digestion is the process by which your 15 body breaks down the food you eat into substances that it can absorb and use. The food changes physically and chemically during digestion.

Food is broken down into smaller pieces with the help of the teeth, it is further made into a smooth paste called bolus, by the action of the tongue and saliva Starch is broken down into simpler sugars by the action of the enzyme, salivary amylase.

The food we swallow travels down the 20 food pipe by peristalsis and enters the stomach through the cardiac sphincter The stomach churns the food into a creamy liquid called chyme, which enters the small intestine through the pyloric sphincter.

The stomach medium is acidic and this helps formation of enzyme pepsin which breaks down proteins into amino acids The liver, pancreas and gall bladder 15 play an important role in digestion.

They are not part of the main digestive tube The liver produces bile, which is stored in the gall bladder. Bile is important for breaking down fats.

The pancreas secretes different

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24 enzymes for the digestion of proteins, carbohydrates and fats. It also secretes bicarbonate to neutralize the acidic nature of food coming from the stomach.

2.4

What happens in the small and large intestines?

What is the role of the liver in the absorption of digested food?



The small intestine is very long with a 10 very large internal surface area because of thousands and thousands of finger-like projections called villi.



Most of the digestion and absorption of food takes place in the small intestine



Digested nutrients are sent to the liver where they are converted, stored and sent to different parts of the body for use



The residual material is sent to the large intestine. Here vitamins, minerals and water are absorbed. The residue is excreted or thrown out of the body through the anus.

Total time

60

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Time: 15 min

ABL 2.1 LEARNING OBJECTIVE - What is digestion? What happens to the food in the mouth?

ADVANCE PREPARATION Material List No. 1

2 3 4 5 6

7

Materials A set of the following items  One bowl (steel or aluminum, cheap and reusable) about 100 ml capacity  Cutter or knife (not too sharp),  One small crusher/pestle,  Two test tubes,  Two spoons  100 ml water in small bottle or beaker  Model of Mouth and teeth  About 50 grams of food (bread or chapatti) that can be cut and crushed into small pieces using knife, pestle, scissors etc.  Iodine solution  Starch powder Labeled diagram/chart of teeth– Reusable Set of Flash cards with names of different parts and enzymes of digestive system (list given below table*) Reusable Chart / models/ flip charts of digestive system Chart paper, 6-8 sheets Chart with all technical terms with common English term and local language term (for example – pharynx/throat/local language term Human torso model

Quantity One set per group

1 per session 1 per group One set per session One set per session One per session

One per session

*List of flash cards

1. Mouth – Teeth, tongue, bolus, saliva, salivary amylase 2. Esophagus, epiglottis, trachea, food pipe, peristalsis 3. Stomach, cardiac sphincter, pyloric sphincter, HCl, pepsin, protein, peptides, chyme

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26 4. Small intestine, duodenum, jejunum, ileum, villi, bile, chyle, trypsin, chymotrypsin, pancreatic amylase, bile, fatty acids

Things to do 1) Put the items in Serial number 1 in one bag or tray marked Set 1.

2) For Instructor preparation-In this exercise, learners will learn about structure and functions of the different parts of the digestive system through a set of exercises, materials and flash cards. They will “construct� the digestive system on the workbench. ((The entire ABL 2 should be done in advance during IMT training and photographs taken of how all the materials for explaining the digestive system are placed on the table at the end of the ABL. These photographs should be used during Instructor training to explain the ABL. (See photographs below)) 3) It will be ideal to have 4 workbenches as in Chemistry session, two on the right of the Instructor and two on the left. All groups should be able to see the Instructor and each other. If tables are not available, use the same arrangement on the floor.

4) Making Starch solution: Heat about 200 ml of water in a beaker. When the water is hot, add 2 spatulas of starch powder and stir well. Continue heating till the water starts to boil.

Safety Precautions Learners should be requested to be careful while using scissors, blades etc.

SESSION Link to known information/previous activity In the previous ABL, we have learnt about the food we eat, what nutrients it contains, why we should eat balanced diets and what happens if there is deficiency of any nutrient. Now let us see what happens to the food once we eat it.

Procedure

Tell the learners the following.

We are now going to study our digestive system and how it works. The digestive system is basically a hollow tube that starts at the mouth and ends in the anus.

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27 Different parts of the hollow tube have different functions and form different organs.

We will do a few activities to “construct” the digestive system from simple everyday material. We will study the structure and function of the different parts.

The first activity will help us to understand that digestion is a mechanical process using the example of the teeth tearing and cutting food. We will also do a small experiment with saliva to understand that digestion is also a chemical process where enzyme molecules play a part. Then we will see what happens to the food in the mouth.

Divide the class into 4 groups of about 10 each. Ask each group to do the following.

1) Take two test tubes marked 1 and 2. In test tube 1, take some amount (about 1 ml) of saliva. In the second test tube, take the same amount (as saliva) of water.

2) Now, add 3 ml of starch solution to both test tubes and shake gently. Add 1 or 2 drops of iodine to both test tubes and keep them aside undisturbed. Note the colour of both solutions as soon as the iodine solution is added.

3) In the meanwhile, the rest of the group will put the food items given (bread, biscuit etc.) in the bowl and start cutting them into smallest possible pieces with cutter/scissors. Once the food finely cut, add a small quantity of water, just enough for it to become a soft, moist ball. Keep it aside.

4) Observe if there are any changes in the solutions in the test tubes after a few minutes.

5) Note that the solutions in both test tubes were blue as soon as starch and iodine solutions were added. Now (after about 5 minutes), the blue colour disappears in the first test tube. There is no change in the second test tube.

Figure 4 – Building the digestive system - 1

UNDERSTANDING THE ACTIVITY Leading questions:(For experiment with saliva) Agastya International Foundation. For Internal Circulation only.

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28 1) What happens to the mixtures in test tubes 1 and 2 on adding Iodine solution?

2) What is different between the two test tubes? What does this test show?

Discussion and explanation

1) Test tube 1 containing Saliva shows a blue colour while test tube 2 containing plain water does not show this change.

2) The difference between the two test tubes is that Test tube 1 contains saliva and Test tube 2 contains water. The colour changes in the test tube with saliva.

We have already seen that when iodine is added to starch solution, it gives a blue colour.

Our little experiment shows that there is something in our saliva that changes the starch. When the starch is changed or broken down the blue colour vanishes.

Saliva contains an enzyme called salivary amylase that helps to break down starch, which is a large and complex molecule into simple sugars. Sugars do not give a blue colour with iodine solution. This breaking down of large molecules into smaller and simpler ones is known as Digestion.

Enzymes are molecules that change the speed of chemical reactions in living things. They are usually made up of proteins. They act like biological scissors, taking large molecules and chopping them into smaller parts.

Enzymes are named according to the substance that they break down. Starch is also known as amylum.

For example, salivary amylase is the enzyme in saliva that breaks down starch”. In the same way, an enzyme that breaks down proteins is called “protease”, An enzyme that breaks down lipids is called “lipase”; an enzyme that breaks down sucrose is called “sucrose” and so on.

We saw in ABL 1 that carbohydrates are a group of foods. Starch, sugars and glycogen are different kinds of carbohydrates. Starch is a complex carbohydrate. Through digestion, it is broken into smaller units, which are mainly different kinds of sugars. These can be disaccharides (made of two units) like maltose and sucrose or monosaccharaides (made up of one unit) like glucose, fructose and galactose. Of these sugars, glucose is the most important for our body processes.

Digestion is the process of breaking down the food we eat into smaller parts that can be used by the body.

The process of digestion starts in the mouth. Here, some of the starch in our food is broken down into sugar.

Leading questions: (For activity of cutting and chopping food items given) 1) Now look at the mixture in the bowl, let us pretend that this is the food that we have eaten. What are the changes?

2) What do the different kinds of teeth do?

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29 3) Is a baby born with teeth?

4) When does a baby start getting teeth?

Discussion and Explanation 1) We chopped and cut the food given to us into small pieces. This function is done for us by the teeth.

Now, ask all learners to feel their upper and lower sets of teeth with the tip of the tongue. Ask them if all teeth feel the same.

(Tip for Instructor: The learners from higher classes may know the names of the different kinds of teeth – facilitate accordingly) 2) Use the model of the teeth for the following explanation and facilitate the following responses from learners.

When we get all our teeth by the time we are 16 or so, we will have 32 teeth, 16 each in the upper and lower jaw. Sometimes people may get new teeth even when they are 30 – these are called the wisdom teeth.

The four pairs of front teeth are sharp and flat – good for cutting food. These are the Incisors.

Next to the incisors, are two pairs of the canines – sharp and pointed, good for tearing food.

After that come the four pairs of the premolars – the shape changes, the top of the tooth is larger.

Then come six pairs of molars, which are even bigger than the premolars.

The last 4 molars (upper and lower jaws, right and left sides) are known as wisdom teeth, which may grow much later in life or not at all.

Now discuss the structure of each tooth using the following information 3) A baby is not born with teeth.

4) The baby starts getting teeth when it is about 6 months old. These are called milk teeth. There are 20 milk teeth by the time the child is about 3 years old. Ask the class if they remember at what age their first tooth fell – collect some answers.

Use the chart of the structure of the tooth in Figure 1 to explain the different parts.

The tooth consists of three main parts externally 1. The crown is the part above the gum that can be seen 2. The neck which is at the level of the gum 3. The root which is embedded in the gum Agastya International Foundation. For Internal Circulation only.

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Each tooth has the following parts: Enamel The hard outer layer of the crown. Enamel is the hardest substance in the body.

Dentine- Not as hard as enamel forms the bulk of the tooth and can be sensitive if the protection of the enamel is lost.

Pulp- Soft tissue containing the blood and nerve supply to the tooth. The pulp extends from the crown to the tip of the root.

Cementum or cement- The layer of bone-like tissue covering the root. It is not as hard as enamel.

The teeth are fixed in the gums, which sit in the jawbones.

Figure 5: Structure of tooth

We should take care of our teeth by brushing regularly and by washing our mouths after every meal. If we do not take proper care, bacteria and germs grow in the mouth. When this happens, the person will get cavities and other problems like gum disease We need to be especially careful after eating sweets - if the mouth is not cleaned properly after eating sweets, bacteria will grow in the mouth and destroy our teeth.

Rubbing teeth with salt or using a neem “datun� is a good way to clean the teeth. Many of our simple traditional practices are very good for the health and do not cost much.

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31

(Note to Instructor – If there is time, you can explain how costly sweets and chocolates, soft drinks and other stuff advertised on TV are really bad both for our health and make us spend money! This will help children become aware of negative things in advertising.)

Now, think about what happens to food in our mouths. The teeth have cut it into small pieces; the tongue has helped to mix it with saliva that makes it moist and easy to swallow. The saliva has also started digesting some of the starch. Food has gone through some mechanical and some chemical digestion in the mouth. The food in this soft, moist, rounded form is called “bolus”.

Now, keep the bowl with the “bolus” and the two test tubes on the left hand side of the table. Put the card marked “salivary amylase near it. Then label with the “Mouth” card. Keep the model of the jaw (if each group has a model) near the “mouth” card

KEY MESSAGES  



Digestion is the process by which your body breaks down the food you eat into substances that it can absorb and use. The food changes physically and chemically during digestion.

Food is broken down into smaller pieces with the help of the teeth, it is further made into a smooth paste called bolus, by the action of the tongue and saliva Starch is broken down into simpler sugars in the mouth by the action of the enzyme, salivary amylase.

LEARNING CHECK 1) The dental formula gives us an easy way of remembering how many of each kind of tooth we have.

Dental formulas record the number of each type of tooth in one half of the upper and lower jaw. Since the left side of the jaw has the same number as the right, only one side is counted. Can you try counting the teeth in your mouth and writing a dental formula?

Answer for Instructor’s reference: The dental formula is 2-1-2-3.

Explanation: In each half of each jaw (upper and lower, adult humans have premolars and 3 molars, 8 in each half of each jaw. The total will be 8x4 =32

2 incisors, 1 canine, 2

(http://www.ask.com/question/dental-formula-for-a-human)

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32 2) Amylases, proteases and lipases are the enzymes that help to break down ------, --------- and --------.

(Answer for Instructor’s reference: Starch, proteins and lipids)

Time: 20 min

ABL 2.2 LEARNING OBJECTIVE - What happens to the food in the esophagus and stomach?

ADVANCE PREPARATION Material List No. 1

Materials Esophagus set consisting of following  

Quantity One set per group

One flexible transparent tube, about 15 inches long and 1 inch diameter, One marble that can be pushed through the tube

2

One set per group Stomach set consisting of following      

3 4

One bowl about 1 liter capacity, Two blunt stirrers (like the one used for mashing greens) Mortar and pestle 250 gms of semi-solid food or food like item for mashing and churning Diluted HCl – 2 ml One cloth bag of 1 liter capacity, filled ¾ths with sand/green gram

Chart 3 of mouth and throat cavities Chart 4 – Food going down the esophagus because of peristalsis

1 per session 1 per session

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Things to do Not Applicable Safety Precautions Not Applicable

SESSION Link to known information/previous activity In the previous activity, we saw what happens to food in the mouth and how it becomes a soft, moist ball called “bolus”. Now let us see what happens when we swallow the food.

Procedure Start with leading questions to get everyone to share their ideas. Then explain what happens in the throat and esophagus using charts with figures 8 and 9.

Figure 6 – Building the digestive system - 2

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Figure 7– Building the digestive system - 3

When that is completed, start the activity for explaining the stomach.

Leading questions: 1) What are all the things that enter the throat or pharynx?

(Answer: The air we breathe, the food we swallow.)

2) Does air and food go into the same place inside the body?

(Answer: No. The air goes into the air pipe or trachea. The food goes into the food pipe.)

3) How does the body make sure that food does not go into the nose or the air pipe?

(Answer: The valve known as epiglottis stops the food from entering the windpipe.)

Discussion and Explanation Chart 3 – Mouth and Throat cavities

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Now use the Chart 3 – Mouth and Throat cavities to explain the following.

When we swallow, two involuntary events happen. The word “Involuntary” means that the action will happen whether we want it to or not. For example, the beating of the heart is “involuntary”.

There are two traffic policemen to make sure that the food goes into the esophagus and nowhere else. The first traffic policeman is a flap of tissue called the soft palate, which is pressed upwards so that food does not enter the nose. The second traffic policeman is the flap of cartilage called epiglottis that tilts down and closes the air pipe when we swallow food.

Now show the different parts - mouth and nose cavities, pharynx and epiglottis.

Note to Instructor – In this section, the activity is a part of the discussion Now, ask the groups to examine the material given to them in the esophagus set and describe them. Ask each group to push the marble through the flexible tube. Ask them to observe that the tube expands and contracts as the marble are pushed through.

Now ask one learner in each group to hold the 15-inch tube with one end at the throat and the other on the chest reaching the stomach. Explain with the help of Diagram 2 that the tube is somewhat like the food pipe or esophagus and the marble is like a piece of food.

Chart 4- Food going down the esophagus because of peristalsis

This wave of muscle contraction to push the food through the digestive tube is called peristalsis.

Remember that the food we eat is soft and moist, like the bolus we made in the earlier activity. It cannot be hard like the marble!

Each mouthful of food takes about 6 seconds to reach the stomach after it is swallowed.

Now pick up the cloth bag in Set 2, how does it feel, what happens when you press it as if to crush the stuff inside.

Ask learners to describe the bag and how it is tied at both ends Explain that this represents the stomach; ask the group to see that the bag is tied above and below so that the material in it cannot fall out.

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36 In the same way, the stomach has two muscular rings or sphincters on either side. (A sphincter is an opening controlled by muscle) The cardiac sphincter stops the mixing of food between the esophagus and the stomach. At the other end is the pyloric sphincter. The word “gastric� is used for processes related to the stomach.

So, the stomach is a bag made of strong muscles that churn and mash the food into pulp helped by gastric juices. The inner lining of the stomach is folded, this allows it to expand when it is full and contract when empty.

Leading question 1) What is hunger? What is appetite?

Discussion and Explanation 1) Hunger occurs when the body needs food. Appetite is the desire to eat. When the stomach is empty or sugar levels in our blood are lower than normal, we begin to feel hungry.

Session continued: 1) Ask the groups to add 5 ml of water to the bowl with the bolus (if it is real food) and stir and mash well.

2) Now add 5 drops of dilute Hydrochloric acid (HCl) and mix well.

3) Add one drop of the mixture to litmus paper and check the pH. It will be acidic.

UNDERSTANDING THE ACTIVITY Leading questions: Set 1 1) Was the pH that you checked acidic or basic?

Discussion and Explanation: Set 1 1) The pH is acidic. Now, explain that the acidic medium in the stomach is because of secretion of Hydrochloric acid.

Glands in the stomach secrete pepsinogen. The acidic medium converts pepsinogen into pepsin, which is an enzyme that helps to break down proteins.

The acidic medium in the stomach kills any bacteria that may be present in the food we have eaten. The inner lining of the stomach also secretes mucus, which protects the stomach lining.

During digestion the pH in the stomach is between 3.5 and 5.5.

Leading question: Set 2 1) What foods are rich in proteins?

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37 2) What are proteins broken down into?

Discussion and Explanation 1) Milk, pulses, beans, eggs, fish and meat are rich in protein.

2) Proteins are broken down into Amino acids.

This means that pepsin will act on the food items like the following – pulses, beans, meat, fish, eggs, milk – and break them down into amino acids.

Other enzymes will be dormant (inactive) in the acidic medium In the gastric phase, acid, enzymes and other substances are released into the stomach cavity. Typically food remains in the stomach cavity for 4-6 hours being broken down by acids and enzymes before leaving for the small intestine.

When the food has been churned into a creamy mixture known as chyme, the pyloric sphincter opens and chyme passes gradually into the small intestine.

The pyloric sphincter opens only partially and about 3 ml of chyme enters at a time into the “C” shaped duodenum, which is the first part of the small intestine. Larger particles of the food continue to be digested in the stomach as the small intestine begins its work.

Now ask learners to keep the oesophagus tube and the stomach “bag” below the mouth materials on their tables. The flash cards with the words “peristalsis” and “oesophagus” should be kept near the oesophagus tube and cards with “HCL”, “pepsin”, “chyme” and “stomach” near stomach bag.

KEY MESSAGES   

The food we swallow travels down the food pipe by peristalsis and enters the stomach through the cardiac sphincter The stomach churns the food into a creamy liquid called chyme, which enters the small intestine through the pyloric sphincter.

The stomach medium is acidic and this helps formation of enzyme pepsin, which breaks down proteins into amino acids.

LEARNING CHECK Answer the following: 1. If the word “gastric” is used for things related to the stomach, what is the word used for things related to the heart: (Answer for Instructor’s reference: “Cardiac”. In the section above, the stomach sphincter closer to the heart side is called cardiac sphincter) 2. --------- prevents the acid in the stomach from damaging its inner lining (Answer for Instructor’s reference: Mucus) 3. Give 3 examples of involuntary movement in the body Agastya International Foundation. For Internal Circulation only.

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38 (Answer for Instructor’s reference: The beating of the heart, closing of air pipe by the epiglottis while swallowing, closing of nasal cavity by the soft palate.)

ABL 2.3 Time: 20 min

LEARNING OBJECTIVE: What is the work done by the liver, gall bladder and pancreas?

ADVANCE PREPARATION

Material list No. Materials 1 Chart 5 of liver, pancreas and gall bladder 2 Set of 2 Test tubes, oil, soap solution

Quantity 1 per session 1 set per group

Things to do Not Applicable Safety precautions Not Applicable

SESSION Link to known information/previous activity We have seen in the previous activity that food is digested in the stomach into a creamy mixture called chime, which goes into the first part of the small intestine – the “C” shaped duodenum. Now the main part of digestion and absorption will start. We will learn about 3 organs that are not part of the main hollow

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39 tube that forms the digestive system but are very important for the process of digestion and absorption.

These are the liver, gall bladder and pancreas.

Procedure Explain the following: The food, in the form of chyme, has now reached the small intestine, which is divided into 3 parts – the C shaped duodenum, the jejunum and the ileum.

Let us stop here for a little to learn about the liver, the pancreas, and the gall bladder.

Although they are not part of the main digestive tract or tube, all three are very important to the process of digestion.

These three organs all share a common function—sending digestive juices to the duodenum Now ask the learners to do the following small activity to find out where the liver is.

All learners will place the left hand over the last three ribs on your right side. Now the left hand is more or less on top of your liver.

Now, explain the following with the help of the chart 5.

Let us find out from this chart where these organs are and what they look like.

Chart 5: - Liver, pancreas and gall bladder

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40 The liver is the second largest single organ in the body and can weigh as much as 2 kgs in an average adult.

The gall bladder is a small bag like structure behind the liver and in front of the stomach. The pancreas is a carrot shaped structure lying in the C formed by the duodenum.

The colour of the organs is the same as shown in the diagram – the liver is reddish brown, the pancreas is cream coloured and the gall bladder is greenish!

Imagine, our insides are in Technicolor!

The main role of these three organs is to send digestive juices to the small intestine.

Digestive fluids from all three converge like tributaries of a river at the common bile duct, and they flow from there into the duodenum. The flow is controlled by a sphincter muscle-ring separating the duodenum and common bile duct.

Let us see what the pancreas sends to the duodenum through the common bile duct.

It sends bicarbonate to neutralise the acidic nature of chyme sent from the stomach.

It sends 2 enzymes – trypsin and chymotrypsin- that break down all proteins into amino acids.

It also sends pancreatic amylase that breaks down carbohydrates and pancreatic lipase that breaks down fats.

The liver is a very important organ and has many different functions. There is an old proverb in English that says, “Life depends on the Liver”.

Now we will look at one important function of the liver. It produces bile, which is very important for the digestion of fats.

The gall bladder stores the bile produced by the liver.

Let us now see how the bile helps in digestion of fats.

Guide learners to perform the following activity in groups: Take two test tubes with water and a few drops of oil. Shake both vigorously to break up the oil drops.

Now add some soap solution to one test tube and shake well.

Let both test tubes stand for about 3 minutes.

In the test tube without soap solution, oil droplets will again join together.

In the test tube with soap solution, the oil droplets will not join. This process is known as emulsification.

The bile juice acts exactly like the soap solution in our experiment. It helps to break up fats in the duodenum.

The duodenum is so smart that when we eat fatty food, hormones released in the duodenum send a message to the gallbladder to contract.

It does so and squeezes bile through the common bile duct into the duodenum. Here the bile helps to emulsify or break down fats into fatty acids.

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41 Learners will now keep the cards marked (one card - liver, gall bladder, bile), (one card -pancreas, bicarbonate, pancreatic amylase, lipase, trypsin, chymotrypsin) just below and to the side of the stomach bag.

Figure 8 – Building the digestive system - 4

Leading questions Not Applicable Discussion and Explanation Not Applicable

KEY MESSAGES   

The liver, pancreas and gall bladder play an important role in digestion. They are not part of the main digestive tube.

The liver produces bile, which is stored in the gall bladder. Bile is important for breaking down fats.

The pancreas secretes different enzymes for the digestion of proteins, carbohydrates and fats. It also secretes bicarbonate to neutralize the acidic nature of food coming from the stomach.

LEARNING CHECK Ask learners to list the key things they have learnt. Guide them to the key messages listed and then put up the chart of key messages. If you have time during the class, make up a small game, quiz or match the following as a learning check. This may have to be done as part of advance preparation.

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42

ABL 2.4

Time: 10 min

LEARNING OBJECTIVE: What happens in the small and large intestines?

What is the role of the liver in the absorption of digested food?

ADVANCE PREPARATION Material List No. Materials 1 Small intestine set consists of following:  One flexible plastic tube ¼ inch diameter and 7 meters long,  One measuring tape,  Thin flexible wire about 6 inches (Small intestine set);  One cardboard box 12” x 8” with a depth of 6”.

One 12” x 8” side should be open. Can use a shoe box of roughly same dimensions without the lid 2 One flexible plastic tube 2 inch diameter and 2 meters long (Large intestine set) 3 Chart with diagram of villi (Figure 5) 4 Thin Copper wire about 10 cms (reusable) 5 One sponge (one normally used in kitchen) 6 One tray with water (tray should be of a size so that the sponge can be immersed in the water) 7 Chart of human digestive system 8 Human torso model

Quantity 1 set per group

1 per group 1 per session 1 per group 1 per session 1 per session 1 per class 1 per class

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43 Things to do Not Applicable Safety Precautions Not Applicable

SESSION Link to known information/previous activity The food has now reached the duodenum and the enzymes and other substances like bile and sodium carbonate have been secreted into the duodenum from the liver, gall bladder and pancreas. Now let us see what happens further to the food.

Procedure Each group will take the 7 meters long thin plastic tube and fit it into a cardboard box that is about 12” x 8” x 6 “. Once this is done, they should fit the wider, 2-meter tube on the outer side surrounding the thinner tube on 3 sides.

Now, each group should take the thin copper wire and bend it in the shape shown in the diagram

Figure 9 – Building the digestive system - 5

UNDERSTANDING THE ACTIVITY Leading questions 1. Is it possible to fit in two tubes that you have fitted into the box, in a person’s abdomen?

2. How can we fit a large paper into a small box?

Discussion and Explanation Note to Instructor: Take learner answers to the above leading questions and move on to explanation.

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44

Now show the picture of the small and large intestines in the chart of the digestive system or the human torso model.

Ask learners to compare the two tubes they fitted in the box to the picture of the small and large intestines. Ask them to note how wonderfully the human body has been made; the small intestine is many times the height of the person.

Figure 10 - Inner layer of small intestine, section showing inner cavity and structure of villi.

The cardboard box with the tubes is something like our abdomens with the small and large intestines. The folded copper wire is something like the inner surface of the intestine shown in Figure 5.

So, we have a small intestine that is about 7 meters long with an inner surface that has thousands and thousands of finger- like projections called villi. Together, this gives a huge surface for absorption of digested food. Each villus has a network of fine blood vessels. The surface of the villi absorbs the digested food and this is carried by the blood vessels to the different parts of the body The small intestine consists of three parts: 1. The C shaped duodenum into which the common bile duct opens. Here the chyme from the stomach is mixed with enzymes and bile from the liver and pancreas. It is broken into molecules small enough to be absorbed and called chyle.

2. The jejunum or the middle part of the small intestine is where food is absorbed and transported to different parts of the body 3. The ileum is the last part where Vitamin B 12 is absorbed.

The following table tells us what happens to the different nutrients, where they are digested and absorbed.

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45 Figure 11 – Digestion of nutrients S. Nutrient No

Process of Digestion Place of Digestion

Enzyme involved

1

Carbohydratesstarch

Mouth

Salivary amylase

2

Carbohydrates

Duodenum

3

Proteins

Duodenum

4

Fats

Duodenum

Pancreatic amylase Trypsin and Chymotrypsin Bile juice and Pancreatic lipase

Converted to Partially converted to maltose Glucose Peptides and amino acids Fatty acids

Place of absorption Jejunum Jejunum Jejunum Jejunum

Once most of the useful molecules from the digested food are absorbed by the small intestine, they go to the liver. The residue passes into the large intestine. Here minerals, vitamins and excess water are absorbed.

Now, let us see what happens to the material that reaches the large intestine.

We will now put this sponge in a tray of water and see what happens. We can see that the sponge absorbs a lot of the water. This is exactly what happens in the large intestine.

After all useful material is digested and sent to liver, the unwanted residue is sent to the large intestine where excess water is absorbed just like the sponge we just saw.

The walls of the large intestine also absorb sodium, chlorine and potassium. The large intestine contains millions of friendly bacteria that convert the undigested food into faeces.

They help to keep away harmful bacteria. If friendly bacteria are disturbed, then harmful bacteria grow unchecked. This results in disease and infection. An infected individual excretes harmful bacteria. Food and water contaminated with harmful bacteria results in spreading infection.

Once all useful molecules and water are absorbed, the waste matter collects in the rectum and is excreted from the body.

To work well, the large intestine needs plenty of fiber and roughage. This material does not get digested but mixes with the waste material and helps in excreting or throwing it out of the body.

Let us follow the absorbed food into the liver.

The digested and broken down food that is absorbed by the fine blood vessels in the villi are carried to the liver where they are processed in different ways for the body to use.

The liver is the body’s chemical processing center. It is the biggest internal organ. The word “hepatic” means anything related to the liver.

(Note to Instructor: You can explain liver functions from the section below according to the level of the class.)

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Explanation of some liver functions 1) Breaking down nutrients into amino acids, glucose, fatty acids The main task of the liver is handling all nutrients digested from the food that you eat and sending them out to the body cells when needed and in the form needed.

2) The liver turns digested carbohydrates into glucose. Glucose is a sugar and the basic unit of carbohydrates. It is the body’s main source of energy and is used for growth and repair. Excess glucose is converted into a substance called glycogen and is stored in the liver and the muscles. It can be turned back into glucose if the body suddenly needs energy. Glycogen is a complex carbohydrate.

Figure 12 – Glucose to Glycogen conversion We can think of glucose and glycogen as Rs. 10/- notes and Rs. 1000/- notes respectively. It is difficult for the body to store glucose. So, many glucose molecules are stacked together as glycogen. When glucose is needed, the glycogen is broken down into smaller glucose molecules and then used.

Glucose levels in the blood are kept steady by the liver. It releases glucose when levels are low and stores glucose in the form of glycogen when there is excess glucose in the blood.

3) The liver also breaks down proteins and stores vitamins and minerals.

Figure 13 – Fats in the liver 4) It produces bile, a bitter greenish, yellow liquid that helps in the digestion of fats Excess fat that you eat is packed off by the liver to be stored as fat around the body 5) The liver also cleans up toxic substances like alcohol and old red blood cells and sends them to the excretory system to be removed from the body.

6) The liver is also a manufacturing site for cholesterol, which is an important part of our cells.

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47

Figure 14 – Building the digestive system - 6 KEY MESSAGES 

The small intestine is very long with a very large internal surface area because of thousands and thousands of finger-like projections called villi.



Most of the digestion and absorption of food takes place in the small intestine



Digested nutrients are sent to the liver where they are converted, stored and sent to different parts of the body for use



The residual material is sent to the large intestine. Here vitamins, minerals and water are absorbed.

The residue is excreted or thrown out of the body through the anus.

LEARNING CHECK Note to Instructor – This ABL is full of information that is new for the learners. It is best to follow with ABL 3, which is a revision of ABL2. This will be the learning check for ABL 2.

Leave all material undisturbed on the worktables after ABL 2 is completed, as they will be needed for ABL 3.

TRY IT YOURSELF Ask learners to do the following 1. Plan a visit to a butcher’s shop near your home, with your parents and if possible see the digestive organs of a sheep/hen and recall what you learnt about the digestive system.

2. Watch how the small children are fed and what kind of food is given to them and think why such food is given.

3. Observe nature carefully, especially earthworms, and the movement of some insects to recognize peristalsis.

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48 4. Think about food preparation techniques. For example, when we make “idli” or “dosa” batter or chutneys-what happens to food? Does this help digestion?

5. To think about natural acids in food.

INTERESTING INFORMATION Did you know?

Mahatma Gandhi said, “Drink your food”. Do you know what he meant? It means that you must chew your food nicely so that it is semi-solid or almost liquid when you swallow it. This helps for better digestion. It also helps your stomach to get ready for the food.

The brain sends a message that you have eaten enough. If you eat very fast without chewing properly, this message reaches after you have eaten much more than you need! This is bad for the health.

The working of the stomach was discovered by a strange accident. In 1822, a man named Alexis St. Martin was badly hit by a shotgun. The bullet had seriously damaged the chest wall and made a hole in his stomach. He was brought to an American army doctor William Beaumont. The doctor saved the patient but he could not close the hole properly and left it bandaged. Beaumont took it as a great opportunity to see the inside of the stomach through the hole. He made some wonderful observations. Beaumont found that the stomach was churning food. Its wall secreted a fluid, which could digest the food. He also observed that the end of the stomach opens into the intestine only after the digestion of the food inside the stomach is completed.

This happened before X-rays and other scientific advances were invented. You can imagine how difficult it was for doctors to “see” what was going on inside a patient!

The largest single organ in the body is the SKIN! The liver is the second largest organ in the body The liver can function quite well even if 50% of its cells are destroyed. If a portion of the liver is removed, the liver cells are able to divide and again become a full sized liver again.

The pancreas produces one of the most important hormones – insulin – that controls sugar levels in our bodies. When enough insulin is not produced or when the insulin is not used properly, too much sugar remains in the blood. This leads to a disease called diabetes.

ADDITIONAL ACTIVITY The following is the script for a role-play or puppet show on the liver and its functions. It can be used as a fun activity if time permits.

The Clever Liver Character 1: - Where is Lata? Why has she not come out to play?

Char2 – Oh, did you not know – she has jaundice Char 1 – What is jaundice – is it a new game?

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49 Char 2 – (Puppet comes down in despair) – Oh!! What shall I do with you! Jaundice is not a game. It is a problem with her liver. Now you will ask me “what is liver” Char 1 – Yes! What is liver?

Char 2 – Liver is a very important organ that helps in our digestion.

Char 1 – You tell me what it does; I will see how important it is Character 2 – It takes the nutrients from digested food and sends them to different parts of the body when and how they are needed. If the liver does not do this work, there is no use of the food that we eat.

Character 1 – Hmmm – Something like the engine of the bus takes the petrol from the tank and makes the bus move.

Character 2 – Okay, you will get one point.

It breaks down digested carbohydrates into glucose - the main source of energy for the body.

Character 1 – So you mean that glucose is everywhere in our body?

Character 2 – The liver is very clever (2). It takes extra glucose and stores it as glycogen. Whenever glucose is needed by some part of the body, it converts glycogen back to glucose and sends it there Character 1 – Did Lata go to the doctor?

Character 2 –Yes, He said that she should not eat any oily food?

Character 1 – So, no bhajji’s and bondas for Lata! (Dances round the room) Character 2 – Stop your dance. I am going to tell you why the doctor said that – the liver produces bile juice, which helps to break down any oil that we eat Character 1 –You remember the drunkard Thimmappa in our village. By the evening, he could not even walk straight. Everyone said he had spoilt his liver with drink.

Character 2 – The liver will remove bad substances like alcohol from our bodies and send it out through the excretory system. But if there is too much of bad substances like Thimmappa, it cannot handle it.

Character 1 - And what else?

Character 2 –It manufactures cholesterol, which is important for many tissues in the body. I can go on and on about the liver but for today we will stop here Character 1 - I am so impressed – Now everyone join me CLEVER LIVER, CLEVER LIVER, CLEVER LIVER

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50

ABL 3 [Revision of digestive system]

Activity

Learning objective

Key messages

Time (min)

3.1

What have we learnt about the digestive system?

As given in the summary chart

40

Total time:

40

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51 Time: 40 min

ABL 3.1 LEARNING OBJECTIVE: What have we learnt about the digestive system in ABL 2?

Note to Instructor: This ABL is meant for revising and consolidating the information in the activities done in ABL 2. Leave all the materials and labels on the worktables undisturbed after completing ABL 2.

ABL 3consists of two activities, which will help learners consolidate what they have learnt about the digestive system. The first learner activity in ABL 3 is to explain the process of digestion from mouth to large intestine using the human torso model or a chart of digestive system. The learners will take turns to explain different parts.

In the second activity, the labels used for different parts of digestive system in ABL 2 are jumbled up.

Learners then have to put them in the right order on the worktable.

ADVANCE PREPARATION Material List No. 1 2 3 4

Materials Human digestive system chart Human Torso model Materials, labels, flip charts used in constructing the model of digestive system Chart – Summary of digestion (sample given below)

Quantity 1 per class 1 per class 1 per group 1 per class

Things to do Leave all the materials on the worktable and the labels undisturbed after ABL 2.

Safety Precautions Not Applicable

SESSION Link to known information/previous activity Tell the learners that we have learnt many new things and new names in ABL 1 and ABL 2. We will now spend some time to consolidate what we have just learnt.

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52 Procedure Now put up the chart of the digestive system and keep the human torso model on the table. Give the learners a few minutes to look at the chart and human torso model.

For Activity 1, ask learners to come in turns and explain what happens in different organs of the digestive system using the human torso model and the chart.

For Activity 2, jumble the labels on the worktables and ask the groups to keep the labels in the right order.

UNDERSTANDING THE ACTIVITY Leading questions Instructor to ask a few questions about the functions of different parts of digestive system to check that all learners have understood Discussion and Explanation Put up the following chart on the board and summarize the process of digestion.

Chart 6 – Summary of Digestion Process of Digestion

S. No

Nutrient

1

Carbohydratesstarch

Mouth

Salivary amylase

2

Carbohydrates

Duodenum

3

Proteins

Duodenum

4

Fats

Duodenum

5

Minerals

-

Pancreatic amylase Trypsin and Chymotrypsin Bile juice and Pancreatic lipase -

6

Vitamins

-

-

-

7

Water

-

-

-

Place of Digestion

Enzyme involved

Converted to Partially converted to maltose Glucose

Place of absorption Jejunum Jejunum

Peptides and amino acids Fatty acids

Jejunum

-

Large intestine Mostly by large intestine, Vitamin B12 is absorbed by ileum Large intestine

Jejunum

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53 8

Fiber

-

-

-

-

KEY MESSAGES As given in the Summary chart

LEARNING CHECK The chart giving the summary of digestion used earlier in this section can be used as a learning check by covering different boxes and asking learners to give the correct word for the covered box.

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54

ABL 4 - Some amazing facts about our digestive system Activity

Learning objective

Key messages

Time (min)

4.1

What do we know about 

The body and the digestive system is a wonderful machine that is our amazing digestive beautifully organized.  It can handle large volumes of system? material during our lives, it is much better than any machine made by human beings  One in six human beings in the world does not get enough to eat; it is very important that we do not waste food.

Total time:

40

40

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Time: 40 min

ABL 4.1 LEARNING OBJECTIVE: What do we know about our amazing digestive system?

ADVANCE PREPARATION Material List No Materials

Quantity

1

Set of 10 questions with 4 optional answers to each 1 set, reusable, question. Each question with its options will be on session one chart (see sample chart below)

2

A board or flipchart stand for putting up question 1 set per session cards and answer options, a second board or chart for answers and scores

3

Bell and stopwatch for keeping time

1 set per session

4

Marker pens, chalk, writing material

1 set per session

5

Answer key (prepare as shown below)

1 per session

per

Sample Chart – Figure 15

On an average, how much saliva do we produce in a day?

Your options are a) 200 ml

b) 500 ml

c) 1000 ml

d) 1500 ml

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56 Things to do Arrange the classroom in such a way that all learners can see what is going on.

Safety Precautions Not Applicable

SESSION Link to known information/previous activity In ABLs 1, 2 and 3, we have seen how interesting and efficient the digestive system is. In this ABL we will get a sense of how the digestive system handles all these complex functions every day of our life by playing a game that you may already know.

Procedure Ask the class if they have seen quiz programs like KaunBanegaCrorepati (KBC) on the TV Divide the class into two groups A and B. Tell them that they may not know the answer but must try to guess based on what they know or just take a chance. Explain as follows how to play the quiz.

The questions will go alternately to both groups.

When the question is asked to one group, they can consult for one minute and then give the answer. Each group will nominate a spokesperson who will give the answer.

If the answer is correct, ask the next question to the second group. If the answer is wrong, the question passes to the other group. If both groups do not get the answer, the Instructor gives the right answer and marks the right answer on the board. Each right answer gets 2 marks. When the group to whom the question gets the right answer, they get 1 mark. Make sure that all learners in the group participate.

Keep putting up the cards with the correct answers and the scores for the two teams.

Start the quiz with a trial round with one or two simple questions.

Trial question 1 – What is the capital of Tamil Nadu?

Your options are 1) Trichy 2) Coimbatore 3) Chennai 4) Vishakapatnam Trial question 2 – Who is the President of India?

Your options are 1) Abdul Kalam 2) L K Advani 3) PranabMukherjee 4) PratibhaPatil Agastya International Foundation. For Internal Circulation only.

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57 Once learners are clear about the process, start the main quiz

Q1 On an average, how much saliva do we produce in a day?

Your options are a) 200 ml b) 500 ml c) 750 ml d) 1500 ml (Note to Instructor: Compare volumes in Questions 1 and 2 to milk packets which all learners would have seen – half liter/500 ml or one liter/1000 ml – this also helps to emphasize the concept of measurement and numbers in science) Q2 An adult’s stomach can hold about 1 liter of food. The stomach is an elastic bag that can expand, how much can it expand?

Your options are a) Two times b) four times c) six times d) eight times Q3 The length of your small intestine is approximately how many times your height.

Your options are a) Two times b) five times c) ten times d) fourteen times Q4 The inner layer of the small intestine has many folds to increase its surface area. Without the folds, its area would be about half a square meter. With the folds, how much is its area increased to?

Your options are a) 20 meters square) 50 meters square c) 100 meters square d) 250 meters square (Note to Instructor: Keep a cloth that is half a square meter to give the class the concept of sizes that we are talking about) Q5 How much of digestion and absorption of food takes place in the small intestine?

Your options are a) 10% b) 30% c) 60% d) 90% Q6 The liver performs many functions, about how many?

Your options are a) 5 b) 25 c) 50 d) more than 100 Agastya International Foundation. For Internal Circulation only.

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58 Q7 Certain hormones send messages to the brain to say that you have eaten enough. These messages reach the brain in a certain amount of time after food is ingested. How much time is that?

Your options are a) 5 minutes b) 20 minutes c) 40 minutes d) 60 minutes Q8 On an average, we digest ------ kgs of food in a lifetime Your options are a) 30 kgs b) 300 kgs c) 3000 kgs d) 30,000 kgs Q9 About one person in ---- in the world does not get enough food to eat and regularly go hungry. Fill in the blank with a number.

Your options are a) 6 b) 18 c) 12 d) 24 Q10 There are many kinds of bacteria in the large intestine Your options are: a) About500 b) About100 c) About50 d) About10

UNDERSTANDING THE ACTIVITY

Leading questions Not Applicable

Discussion and Explanation Answers for Instructor’s reference - 1 – d; 2 – b; 3 – b; 4 – d; 5 – d; 6 – d; 7 – b; 8 – d; 9 – a; 10 – a.

After the quiz, go through all the answers with the class.

Emphasize how wonderful and efficient the digestive system is.

Spend a little time talking about the importance of eating nutritious food, about taking care of our bodies by doing so.

As socially responsible citizens, all of us need to make sure that we do not waste food when so many people in the world are going hungry.

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59

KEY MESSAGES   

The body and the digestive system are wonderful and complex machines that are beautifully organized.

The digestive system can handle large volumes of material during our lives; it is much better than any machine made by human beings.

One in six human beings in the world does not get enough to eat; it is very important that we do not waste food.

LEARNING CHECK Not Applicable

TRY IT YOURSELF Play the quiz with your fellow learners, family and explain the amazing facts

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60

ABL 5 -Feeding habits in the animal kingdom

Activity

Learning objective

Key messages

Time (min)

5.1

How do different kinds  of animals feed and  digest their food?

There is a huge variety of feeding and digestive habits even among animals that we commonly see.

The animal body is adapted so that it can feed efficiently.

Total time:

60

60

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61

Time: 45 min

ABL 5.1 LEARNING OBJECTIVE: How do different kinds of animals feed and digest their food?

ADVANCE PREPARATION Material List No Materials A4 size pictures of the following animals 1 amoeba, hydra, starfish, earthworm, mosquito, frog, cow, elephant.

Quantity 1 set per session

2

A 4 size envelopes with note on the following ! set per session animals stuck on them - amoeba, hydra, starfish, earthworm, mosquito, frog, cow, and elephant.

3

Set of Cards for the “Match the following� game; 1 set per group each card will have text from each box in the table given below in Columns A and B (See Resource Material 5 below)

Things to do Prepare material, charts, cards etc. as required from text and pictures given below. Print out the note on each animal and paste it on the A4 size envelopes. Take the A4 size picture of an animal and put it into the envelope that has a note about that animal.

Safety Precautions Not Applicable

SESSION Link to known information/previous activity In the ABLs 1-4, we have seen how complex and efficient the human digestive system is. Now we look at different members of the animal kingdom with different kinds of food habits and digestion processes.

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62 Divide the learners into 8 groups and give each group the envelope for one animal. Give them 5 minutes to read and discuss the contents.

Note to Instructor: Make sure that you do not give away the name of the animal while distributing the envelopes.

One member from each group should then share the contents of the note with the larger group and ask them to guess what animal is being talked about. The group should show the picture of the animal after giving some time for their friends to guess.

Then put the picture up on the board.

Note to Instructor: You will have to help some of the groups if they are not able to read easily. Also make sure to tell the learners that they should not give away the name of the animal before the larger group has guessed.

Amoeba Note: I keep on changing my shape. If I want to move in a particular direction, I push out a finger like projection from my body in that direction and my whole body follows. This projection is called my pseudopodia or false feet. In this way I move and catch my food. When I sense the food nearby, I push my projection around the food particle and trap it in a food vacuole. Now, I secrete enzymes into the food vacuole and the food is digested and absorbed for growth, maintenance and multiplication of my body. Finally, I throw the undigested food out of the vacuole.

WHO AM I?

Figure 16 - Amoeba

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63 Hydra Note: I am a small organism, just a few millimeters long. I live in water. I’m quite lazy. I attach myself to rocks and stones underwater. I have a cylindrical body and a number of long projections called tentacles. Do you know who I am already? No? Here are some more clues. Since I don’t move, I use my tentacles to help me get food. I have poison bags on my tentacles. I keep moving the tentacles to bring smaller water organisms within reach and then I “shoot” the poison into the prey and paralyze it. Now that the prey cannot move, I bring it to my mouth with the help of my tentacles. I have a hollow cavity inside where I secrete enzymes and digest my food. Since I am tiny and my cells are very thin-walled, my cells directly absorb the digested food and they throw out waste into the surrounding water.

WHO AM I?

Figure 17 – Hydra

Starfish Note: I am a small animal, people call me a fish but I am not a fish. My body is shaped like a star. I have a tiny mouth opening on the underside of my body. Do you know who I am? I eat small animals called clams and mussels, which are covered with hard shells of Calcium carbonate. I also eat tiny fish and snails. I open their hard shells by wrapping my tentacles around their body.

The most special thing about me is that I push my stomach out of my mouth into the open shell and I digest the animal. Then I take my stomach back into my body. This allows me to eat larger prey that cannot fit into my small mouth.

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http://jklsciencelab.weebly.com/uploads/2/0/6/4/2064940/6012088_orig.jpg Figure 18 – Starfish Earthworm Note: I live in the soil. I feed on organic matter from the soil. I eat large quantities of soil along with the food. My body digests the organic matter as the soil passes through my intestines and the rest of the soil is thrown out as I move along in the soil.

WHO AM I?

Note - Remember that we said the earthworm moves by peristalsis in the same way food moves down out esophagus.

Figure 19 – Earthworm

http://2.bp.blogspot.com/OSjpiw4golM/UL7NRciNhXI/AAAAAAAAALQ/6npK9Kw9qyI/s1600/41_09aEarthwormCanal-L.jpg Agastya International Foundation. For Internal Circulation only.

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Mosquito Note: I bite you almost everyday. I put a needle like tube into your skin. Through this tube I send a substance that stops your blood from clotting or solidifying. Then, I use the tube like a straw to suck your blood into my body. This is called fluid feeding. You skin will start itching when I bite you.

WHO AM I?

Figure 20 – Mosquito

http://www.homelanddefensecorp.com/images/mosquito-anatomy.gif

Frog Note: I can live in water and on land. I have a slippery body. I jump a lot love to eat insects. I have a long tongue, which is attached to the front of my mouth. It is not like your tongue, which is attached to the back of your mouth. I wait for an insect to come along and I throw my sticky tongue out and catch it.

WHO AM I?

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Figure 21 – Frog

http://slohs.slcusd.org/pages/teachers/rhamley/Biology/Frog%20Dissection/tongue.GIF

Python Note: I have a very long and flexible body. I have no hands or feet and I crawl on the ground or on top of trees.

Sometimes I am poisonous and a person I bite may die. I eat small animals like frogs, mice, rats etc. I swallow my food whole. Sometimes when I am really hungry, I can even swallow a whole deer!

WHO AM I?

Figure 22 – Python

http://animal.memozee.com/animal/a7/Morelia_bredli01Bredl_s_Python_eating_a_ratby_Dennis_Desmond.jpg Agastya International Foundation. For Internal Circulation only.

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Cow Note: I am a big animal. You see me very often. I am chewing all the time even when I am not feeding. My stomach has many chambers (unlike yours, which has just one). Mine has four chambers! The first one is called rumen. I mostly eat grass, which is very rich in cellulose. When I eat, I quickly swallow the food without chewing and store it in the rumen. Here, my food is partially digested into a substance called ‘cud’.

The cud comes back into my mouth in small lumps and I chew it further.

I have special bacteria in the rumen that help me digest cellulose. I provide a very useful food item for you.

WHO AM I?

Note - Human beings and many animals cannot digest cellulose.

Figure 23 – Cow and Rumen Agastya International Foundation. For Internal Circulation only.

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http://sci.waikato.ac.nz/farm/images/ruminant%20stomach%20RHS%20web.png

Elephant Note: I am a very big and strong animal, many times bigger than Human beings. My digestive system is not very good. I am a herbivore that means I only eat plants. I spend almost 16 hours a day collecting plant food.

My diet is at least 50% grasses, supplemented with leaves, bamboo, twigs, bark, root, and small amounts of fruits, seeds and flowers. I can only digest 40% of what I eat. So, I have to make up for this lack of efficiency by eating large volumes of food. I can consume 140-270 kg of food a day. 60% of that food leaves my body undigested!

WHO AM I?

Figure 24 – Elephant

http://www.mizozo.com/images/item_images/3000/2597_gallery.jpg

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UNDERSTANDING THE ACTIVITY Leading questions 1. Did all these animals have similar digestive systems?

2. What did we learn about the digestive system from all these different examples?

Discussion and Explanation 1. No. There is a huge variety in feeding and digestive habits among different animals. They also eat different types of food in different ways. Their body processes this food and digests it in a variety of ways.

2. All the bodies of animals are adapted in such a way that they can feed themselves most efficiently.

KEY MESSAGES  

There is a huge variety of feeding and digestive habits even among animals that we commonly see.

The animal body is adapted so that it can feed efficiently.

LEARNING CHECK Match the following: Note to Instructor – Table 1 below shows the correct pairs. You can use a jumbled table as in Table 2 or use separate cards for each box to play the “match the following” game. This can take up to 15 minutes.

Table 1 (Correct information) Column A Column B Amoeba Unicellular animal living in water, whole body moves towards and takes in food, forms food vacuole and digests the food Hydra Tiny animal fixed to rocks in water, has poison bags on its tentacles, shoots poison into prey and then takes it in Starfish Tiny water animal. Its stomach comes out through its mouth, takes in the prey and digests it.

Earthworm This animal eats a lot of mud with its food. As it keeps moving, the extra mud is excreted Frog Its tongue is attached to the front of the mouth. This way it can catch insects that are some distance away Mosquito It has a needle like structure that it uses to puncture the skin of its prey Cow This animal has a stomach with 4 chambers. It swallows food and brings it back to the mouth and keeps on chewing most of the time Elephant This animal can digest only 40% of what it eats. So it keeps on eating the whole day Agastya International Foundation. For Internal Circulation only.

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Match the following Table 2 (Jumbled information) Column A

Column B

Starfish

Unicellular animal living in water, whole body moves towards and takes in food, forms food vacuole and digests the food

Mosquito

Tiny animal fixed to rocks in water, has poison bags on its tentacles, shoots poison into prey and then takes it in

Elephant

Tiny water animal. Its stomach comes out through its mouth, takes in the prey and digests it.

Cow

This animal eats a lot of mud with its food. As it keeps moving, the extra mud is excreted

Amoeba

Its tongue is attached to the front of the mouth. This way it can catch insects that are some distance away

Hydra

It has a needle like structure that it uses to puncture the skin of its prey

Earthworm

This animal has a stomach with 4 chambers. It swallows food and brings it back to the mouth and keeps on chewing most of the time

Frog

This animal can digest only 40% of what it eats. So it keeps on eating the whole day

TRY IT YOURSELF 1. Observe how a frog catches its prey. You will have to be very quiet and perhaps use a pair of binoculars to observe the frog.

1. Observe how the cow chews the cud almost all the time.

2. If you know a farmer who has a vermiculture pit, you will be able to observe the earthworms moving in a peristaltic motion and eating their food along with mud. Because of this, you get excellent manure in the vermiculture pit.

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71 APPENDIX Nutrition table 1 – Chart 1 and Chart 2 Column 1 Groups. Nutrient

Column 2 Food items rich in nutrient

Column 3 Used by body for

Column 4 Deficiency leads to

Macronutrients

Needed for growth and repair of body, Daals, beans, peas, building and repair soyabean of cells and tissues, Milk, eggs, fish, meat known as bodybuilding foods

1

Proteins

2

Rice, wheat, potato, Carbohydr papaya, melon, ates sugarcane, maize, mango

3

Fats

Vegetable fats – Groundnuts, sesame (til), nuts, sunflower, coconut, mustard, soyabean oils Animal fats – Meat, fish, ghee milk, butter, cream

Provide energy for the body

Provide energy to the body, more than energy provided by equal amount of carbohydrates. Fats give us 9 calories per gram energy as compared to 4 calories per gram from carbs and proteins.

Fats are important for absorption of fatsoluble vitamins, some fatty acids (unit of fats) come only from the diet and are needed for

Protein deficiency in children, which leads to, stunted growth and becomes a lifelong health problem. Protein deficiency over a period of time leads to a disease called Kwashikor, in which there is swelling of different parts of the body. In children, this can be seen as heavy swelling of the abdomen.

Leads to weight loss and weakness.

If the diet is deficient in both carbohydrates and proteins for a long period of time, the growth may stop completely.

Too much fat leads to overweight or obesity which over a period of time can lead to heart attacks

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72 every cell in the body.

Micronutrients 4 Vitamins Vitamin A

Milk, carrots, fish oil

Vitamin B, actually group of vitamins called B Green leafy Complex vegetables, beans, (B1, B2, sprouted daals B3, B6, and B12Pantot henic acid, Folic acid.

Vitamin C

Vitamin D

5

Lemon (Nimbu), Gooseberry (amla), orange, tomato, guava Milk, butter, eggs, fish and liver. Our bodies prepare Vit D in the presence of sunlight

Keeps eyes and skin healthy

Poor vision, loss of vision in darkness (night), sometimes complete loss of vision

Keeps general health good and muscles healthy

Beriberi, pellagra, pernicious anemia; (see Instructor Note 4 below this table) Weak muscles and very little energy to work. Folic acid deficiency causes a form of anemia especially in pregnant women. This can be prevented by giving pregnant women iron and folic acid supplements. You may have seen this information in TV health advertisements.

Helps the body fight infections

Scurvy, bleeding gums, wounds take longer time to heal

Helps body to absorb calcium needed for healthy bones and teeth

Rickets - Bones of children become soft and bent

Vitamin E

Sunflower seeds, almonds, spinach, papaya

Vitamin K

Tulsi, coriander, spring onions, cabbage, cucumber

Protect skin from UV light, helps cells communicate Problems with liver and effectively, prevents reproductive system cell damage from free radicals Important for proper blood Problems in blood clotting clotting

Seafood and salt water fish, seaweed, and iodized salt.

Good vegetable sources, if they are

Iodine is necessary for the body to make the thyroid hormone which regulates many

Minerals

Iodine

Goiter -Glands in the neck appear swollen, mental disability in children

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Phosphor us

Calcium

Iron

grown in iodine-rich soil are garlic, soybeans, spinach and turnip greens.

Milk, bananas, beans, almonds (badam), cashews, cheese, egg, chicken, garlic Milk, cheese and yoghurt, eggs small fresh or dried fishes with the bones and fish sauces containing the fish bones; white beans; tofu (soybean); almonds and sesame seeds.

Green leafy vegetables, apples, pears, beans, soybeans and tofu, dried fruits. Red meat, liver, fish, eggs, chicken.

body systems,

Important for keeping the bones healthy Needed for healthy bones and teeth; Calcium is essential for healthy bone growth and for nerve and muscle functions; it may protect against high blood pressure.

Calcium is the most abundant mineral in the body Iron is needed in the blood and muscles as part of the system that carries oxygen throughout the body to be used for energy production in the cells.

Joint pain and stiffness, low energy

Bone and tooth decay Weak bones, tooth decay

Anemia, Weakness

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74 Nutrient Percentage Cards

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