In the preceding chapters you came across a large variety of organisms, both unicellular and multicellular, of the animal kingdom. In unicellular organisms, all functions like digestion, respiration and reproduction are performed by a single cell. In the complex body of multicellular animals the same basic functions are carried out by different groups of cells in a well organised manner The body of a simple organism like Hydra is made of different types of cells and the number of cells in each type can be in thousands. The human body is composed of billions of cells to perform various functions. How do these cells in the body work together? As you have already learnt in your earlier classes, in multicellular animals, a group of similar cells alongwith intercellular substances perform a specific function. Such an organisation is called tissue.
You may be surprised to know that all complex animals consist of only four basic types of tissues These tissues are organised in specific proportion and pattern to form an organ like stomach, lung, heart and kidney. When two or more organs perform a common function by their physical and/or chemical interaction, they together form organ system,e g , digestive system, respiratory system, etc. Cells, tissues, organs and organ systems split up the work in a way that exhibits division of labour and contribute to the survival of the body as a whole
7.1 O O S RGAN AND R G A N YSTEM
The basic tissues as you have learnt in earlier classes, organise to form organs which in turn associate to form organ systems in the multicellular organisms Such an organisation is essential for more efficient and better coordinated activities of millions of cells constituting an organism. Each
NCERT LINE BY LINE QUESTIONS
1. Identify the correct statement(s):
1. In unicellular organisms, all functions like digestion, respiration and reproduction are performed by multiple cells
2. In multicellular organisms, different groups of cells carry out specific basic functions.
3. Hydra's body consists of only a single type of cell
4. The human body consists of only thousands of cells.
(a) 2 only
(b) 1 and 3
(c) 2 and 4
(d) All are incorrect
2. Assertion (A): Hydra is composed of different types of cells.
Reason (R): All types of cells in Hydra perform identical functions.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
3. Arrange the following in correct order from smallest unit to largest functional organization: 1 Tissue
2. Organ
3. Cell
4. Organ system
(a) 3 2 1 4
(b) 4 3 1 2
(c) 1 2 3 4
(d) 3 1 2 4
4. Assertion (A): Cells, tissues, organs and organ systems exhibit division of labour
Reason (R): Such division helps each system split up the work and enhance survival of the organism.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false
(d) A is false but R is true.
5. A group of similar cells along with perform a specific function and form tissue.
(a) organelles
(b) intercellular substances
(c) chromosomes
(d) muscular contraction
6. In multicellular animals, all functions are performed by a single undifferentiated cell.
True or False:
7. Assertion (A): Organ systems contribute to survival of the body
Reason (R): A single tissue can perform all complex bodily functions.
(a) Both A and R are true, R explains A
(b) Both A and R are true,R does not explain A
(c) A is true, R is false
(d) A is false, R is true
8. “Since all unicellular organisms perform all functions, they must have organs for each function ”
(a) False because unicellular organisms lack organs
(b) True because organelles behave like organs
(c) True because each cell can replicate organlevel tasks
(d) False because tissues are present instead of organs
9. Choose the most appropriate explanation for the statement: "Tissues are organized in specific proportion and pattern to form an organ."
(a) It reflects random cell accumulation
(b) It refers to a precise structural arrangement needed for organ function
(c) It explains how organs create new tissues
(d) It suggests tissues are temporary structures
Reprin
organ in our body is made of one or more type of tissues For example, our heart consists of all the four types of tissues, i.e., epithelial, connective, muscular and neural. We also notice, after some careful study that the complexity in organ and organ systems displays certain discernable trend This discernable trend is called evolutionary trend (You will study the details in class XII). In this chapter, you are being introduced to morphology and anatomy of frog Morphology refers to study of form or externally visible features. In the case of plants or microbes, the term morphology precisely means only this. In case of animals this refers to the external appearance of the organs or parts of the body The word anatomy conventionally is used for the study of morphology of internal organs in the animals. You will learn the morphology and anatomy of frog representing vertebrates.
7.2 FR O G S
Frogs can live both on land and in freshwater and belong to class Amphibia of phylum Chordata. The most common species of frog found in India is Rana tigrina.
They do not have constant body temperature i.e., their body temperature varies with the temperature of the environment Such animals are called cold blooded or poikilotherms. You might have also noticed changes in the colour of the frogs while they are in grasses and on dry land. They have the ability to change the colour to hide them from their enemies (camouflage). This protective coloration is called mimicry You may also know that frogs are not seen during peak summer and winter. During this period they take shelter in deep burrows to protect them from extreme heat and cold. This is known as summer sleep (aestivation) and winter sleep (hibernation) respectively
7.2.1 Morphology
condition. The colour of dorsal side of body is generally olive green with dark irregular spots. On the ventral side the skin is uniformly pale yellow The frog never drinks water but absorb it through the skin.
Body of a frog is divisible into head and trunk (Figure 7.1). A neck and tail are absent. Above the mouth, a pair of nostrils is present. Eyes are bulged and covered by a nictitating membrane that protects them while in water. On either side of eyes a membranous tympanum (ear) receives sound signals The forelimbs and hind limbs help in
Figure 7 1 External features of frog
NCERT LINE BY LINE QUESTIONS
10. Which of the following statements are correct about frogs?
1.Frogs belong to phylum Arthropoda.
2 Frogs of India commonly belong to Rana tigrina.
3.Frogs can survive both in terrestrial and freshwater habitats.
4 Frogs have constant body temperature
(a) All are correct (b) 1 and 2 only
(c) 3 and 4 only
(d) 2 and 3 only
11. Identify the INCORRECT statement based on frog adaptations:
(a) Frogs exhibit mimicry to escape predators
(b) Frogs are hermaphrodites
(c) Frogs can change colour on grass or dry land
(d) Frogs undergo aestivation and hibernation
12. Match the following terms with their features:
Column A Column B
A. Poikilotherms 1. Can change body colour
B Camouflage 2 Mimicry
C. Mimicry 3. Variable body temperature
D. Aestivation 4. Summer sleep
E. Hibernation. 5. Winter sleep
(a) A-2, B-1, C-3, D-5, E-4
(b) A-1, B-3, C-4, D-5, E-2
(c) A-3, B-1, C-2, D-4, E-5
(d) A-3, B-2, C-1, D-4, E-5
13. Choose the correct option from the following :
1. Frog’s dorsal side is usually green with irregular dark patches.
2 Frog's ventral side is pale yellow and uniformly colored.
3.Skin is smooth and rough for aquatic adaptation.
4 Frog’s skin secretes mucus to keep it moist
(a) All are correct
(b) 1, 3 and 4 are correct
(c) Only 2 is correct (d) 1, 2 and 4 are correct
14. Which two statements, when combined, explain why frogs do not need to drink water?
1.Frog skin is moist due to mucus.
2 Frog skin can absorb water
3.Frogs have a urinary bladder that stores water.
4.Frogs drink water through their tongue.
(a) 3 and 4 (b) 1 and 3
(c) 2 and 4 (d) 1 and 2
15. The external ear in frogs is represented by which receives sound signals
(a) tympanum
(b) stapes
(c) pinna
(d) nictitating membrane
16. Which of the following statements are false regarding frog head morphology?
1.A neck is present.
2.A tail is absent.
3 Eyes are bulged and covered by nictitating membrane.
4.Forelimbs help in reproduction.
(a) Only 3
(b) 2 and 3 only
(c) 1 and 4 only
(d) Only 4
17. In frogs, both forelimbs and hind limbs help in movement. (False\True)
18. Which feature helps frogs protect their eyes underwater?
(a) Tympanum
(b) Pupil dilation
(c) Eyelids
(d) Nictitating membrane
19. Identify the flaw in the following statement: “Frogs regulate their internal body temperature through internal physiological processes ”
(a) True for all amphibians
(b) Incorrect – frogs are cold-blooded and depend on the environment
(c) Correct only in summer
(d) True when they aestivate
swimming, walking, leaping and burrowing. The hind limbs end in five digits and they are larger and muscular than fore limbs that end in four digits. Feet have webbed digits that help in swimming Frogs exhibit sexual dimorphism
Male frogs can be distinguished by the presence of sound producing vocal sacs and also a copulatory pad on the first digit of the fore limbs which are absent in female frogs.
7.2.2
Anatomy
The body cavity of frogs accommodate different organ systems such as digestive, circulatory, respiratory, nervous, excretory and reproductive systems with well developed structures and functions (Figure 7.2).
T h e d i g e s t i v e s y s t e m c o n s i s t s o f a l i m e n t a r y c a n a l a n d d i g e s t i v e g l a n d s
T h e a l i m e n t a r y c a n a l i s s h o r t b e c a u s
l e n g t h o f i n t e s t i n e i s r e d u c e d . T h e m o u t h o p e n s i n t o t h e b u c c a l c a v i t y t h a t
l e a d s t o t h e o e s o p h a g u s t h r o u g h p h a r y n x O e s o p h a g u s i s a s h o r t t u b e t h a t
o p e n s i n t o t h e s t o m a c h w h i c h i n t u r n c o n t i n u e s a s t h e i n t e s t i n e , r e c t u m
a n d f i n a l l y o p e n s o u t s i d e b y t h e c l o a c a . L i v e r s e c r e t e s b i l e t h a t i s s t o r e d i n
t h e g a l l b l a d d e r P a n c r e a s , a d i g e s t i v e g l a n d p r o d u c e s p a n c r e a t i c j u i c e
F i g u r e 7 2 D i a g r a m m a t i c r e p r e s e n t a t i o n o f i n t e r n a l o r g a n s o f f r o g s h o w i n g c o m p l e t e d i g e s t i v e s y s t e m
2025-26
NCERT LINE BY LINE QUESTIONS
20. Identify the correct statements about frog locomotion:
1.Hind limbs end in four digits and are larger than forelimbs
2.Forelimbs have five digits and aid in leaping.
3.Hind limbs are muscular and end in five digits.
4 Hind limbs assist in swimming and burrowing.
(a) 2 and 3
(b) 1 and 4
(c) 3 and 4
(d) All are correct
21. Assertion (A): Male frogs are indistinguishable from females
Reason (R):both possess vocal sacs and a copulatory pad.
(a) Both A and R are true; R is correct explanation
(b) Both A and R are true; R is not correct explanation
(c) A is true, R is false
(d) A is false, R is false too
22. In male frogs, a is present on the first digit of forelimbs, absent in females.
(a) tympanum
(b) copulatory pad
(c) mucus gland
(d) vocal sac
23. Frog’s feet have webbed digits that assist in swimming.
(True \False)
24. Match the following
Column A Column B
A. Liver 1. Opens to cloaca
B. Intestine 2. Secretes bile
C. Rectum 3. Digestion and absorption
D Pancreas 4 Secretes pancreatic juice
(a) A-2, B-4, C-3, D-1
(b) A-4, B-2, C-1, D-3
(c) A-1, B-4, C-3, D-2
(d) A-2, B-3, C-1, D-4
25. Chronological order of food passage in frog:
1.Mouth
2.Stomach
3 Cloaca
4.Pharynx
5.Oesophagus
6.Intestine
7 Rectum
(a) 1 2 4 5 6 3 7
(b) 1 4 5 2 6 7 3
(c) 1 5 4 2 6 7 3
(d) 4 1 5 2 6 7 3
26. The alimentary canal in frogs is short because:
(a) Frogs are herbivores and require more space
(b) Frogs do not have a stomach
(c) Frogs are carnivores, requiring less digestion time
(d) Frogs lack intestine
27. Which of the following structures is NOT part of frog’s digestive system?
(a) Gall bladder
(b) Ureter
(c) Stomach
(d) Intestine
28. Which combination of organs are responsible for enzymatic and bile secretions?
(a) Liver and kidney
(b) Stomach and gall bladder
(c) Liver and pancreas
(d) Pancreas and urinary bladder
29. Assertion (A): Frogs can regulate digestion, excretion, and reproduction through one common structure.
Reason (R): The cloaca is a terminal structure shared by three organ systems.
(a) Both A and R are true; R explains A
(b) Both A and R are true; R does not explain A
(c) A is true; R is false
(d) A is false; R is true
containing digestive enzymes. Food is captured by the bilobed tongue. Digestion of food takes place by the action of HCl and gastric juices secreted from the walls of the stomach Partially digested food called chyme is passed from stomach to the first part of the small intestine, the duodenum. The duodenum receives bile from gall bladder and pancreatic juices from the pancreas through a common bile duct Bile emulsifies fat and pancreatic juices digest carbohydrates and proteins. Final digestion takes place in the intestine. Digested food is absorbed by the numerous finger-like folds in the inner wall of intestine called villi and microvilli The undigested solid waste moves into the rectum and passes out through cloaca.
Frogs respire on land and in the water by two different methods. In water, skin acts as aquatic respiratory organ (cutaneous respiration). Dissolved oxygen in the water is exchanged through the skin by diffusion On land, the buccal cavity, skin and lungs act as the respiratory organs. The respiration by lungs is called pulmonary respiration. The lungs are a pair of elongated, pink coloured sac-like structures present in the upper part of the trunk region (thorax) Air enters through the nostrils into the buccal cavity and then to lungs. During aestivation and hibernation gaseous exchange takes place through skin. The vascular system of frog is well-developed closed type. Frogs have a lymphatic system also. The blood vascular system involves heart, blood vessels and blood The lymphatic system consists of lymph, lymph channels and lymph nodes. Heart is a muscular structure situated in the upper part of the body cavity. It has three chambers, two atria and one ventricle and is covered by a membrane called pericardium. A triangular structure called sinus venosus joins the right atrium. It receives blood through the major veins called vena cava. The ventricle opens into a sac- like conus arteriosus on the ventral side of the heart The blood from the heart is carried to all parts of the body by the arteries (arterial system). The veins collect blood from different parts of body to the heart and form the venous system. Special venous connection between liver and intestine as well as the kidney and lower parts of the body are present in frogs. The former is called hepatic portal system and the latter is called renal portal system. The blood is composed of plasma and cells. The blood cells are RBC (red blood cells) or erythrocytes, WBC (white blood cells) or leucocytes and platelets. RBC’s are nucleated and contain red coloured pigment namely haemoglobin. The lymph is different from blood. It lacks few proteins and RBCs The blood carries nutrients, gases and water to the respective sites during the circulation. The circulation of blood is achieved by the pumping action of the muscular heart. The elimination of nitrogenous wastes is carried out by a well developed excretory system. The excretory system consists of a pair of kidneys, ureters, cloaca and urinary bladder. These are compact, dark red and bean like structures situated a little posteriorly in the body cavity on both sides of vertebral column. Each kidney is composed of several structural and functional units called uriniferous tubules or nephrons. Two ureters emerge from the kidneys in the male frogs The ureters act as urinogenital duct which opens into the cloaca. In females the ureters and
NCERT LINE BY LINE QUESTIONS
30. Match the following digestive structures with their functions in frogs:
32. Assertion (A): Digestion in frogs begins in the stomach and continues till the intestine
Reason (R): Enzymes from pancreas and bile duct are released into the rectum.
(a) A and R are true, R explains A (b) A and R are true, R doesn’t explain A (c) A is true, R is false (d) A is false, R is true
33. Which of the following organs participate in respiration in frogs?
1.Skin
2. Liver
3 Lungs 4 Buccal cavity
(a) 1 and 2 only (b) 1, 3, and 4 only (c) 2, 3, and 4 only (d) All of them
34. Chronological sequence of air passage in frog respiration:
1 Lungs
2.Nostrils
3.Trunk region
4.Buccal cavity
(a) 2 4 1 3
(b) 2 4 3 1
(c) 4 2 1 3
(d) 2 4 1 3
35. Assertion (A): Frog lungs are pink sac-like structures located in the upper trunk.
Reason (R): They are responsible for cutaneous respiration.
(a) Both A and R true; R explains A
(b) A true; R false
(c) A false; R true
(d) Both false
36. Choose the correct statements from the following and mark the correct option from the given below:
1.Lymph lacks RBCs and contains only WBCs and proteins
2 Blood transports waste, nutrients and gases
3.Lymph vessels are part of the excretory system.
4.The frog heart is enclosed by a pericardial membrane
(a) 1, 2 and 4 are correct (b) 1 and 3 only
(c) Only 4 (d) All are correct
37. Which of the following accurately describes frog heart structure?
(a) 2 atria, 1 ventricle, no pericardium
(b) 2 ventricles, 1 atrium, covered by cloaca (c) 2 atria, 1 ventricle, enclosed by pericardium
(d) 2 atria, 2 ventricles, enclosed by ureter
38. Match the circulatory components with their descriptions:
Column A
Column B
A Sinus venosus 1 Between kidney and
lower body
B. Conus arteriosus 2. Between liver and
Intestine
C. Hepatic portal 3. Receives blood from
D. Renal portal 4. Arterial output of
(a) A-1, B-3, C-2, D-4
(b) A-2, B-3, C-1, D-4
(c) A-3, B-2, C-4, D-1
(d) A-4, B-1, C-3, D-2
vena cava ventricle
oviduct open seperately in the cloaca. The thin-walled urinary bladder is present ventral to the rectum which also opens in the cloaca The frog excretes urea and thus is a ureotelic animal Excretory wastes are carried by blood into the kidney where it is separated and excreted. The system for control and coordination is highly evolved in the frog. It includes both neural system and endocrine glands The chemical coordination of various organs of the body is achieved by hormones which are secreted by the endocrine glands. The prominent endocrine glands found in frog are pituitary, thyroid, parathyroid, thymus, pineal body, pancreatic islets, adrenals and gonads. The nervous system is organised into a central nervous system (brain and spinal cord), a peripheral nervous system (cranial and spinal nerves) and an autonomic and parasympathetic). There are ten pairs of cranial nerves arising from the brain Brain is enclosed in a bony structure called brain box (cranium). The brain is divided into fore-brain, mid-brain and hind-brain Forebrain includes olfactory lobes, paired cerebral hemispheres and unpaired diencephalon. The midbrain is characterised by a pair of optic lobes Hind-brain consists of cerebellum and medulla oblongata. The medulla oblongata passes out through the foramen magnum and continues into spinal cord, which is enclosed in the vertebral column. Frog has different types of sense organs, namely organs of touch (sensory papillae), taste (taste buds), smell (nasal epithelium), vision (eyes) and hearing (tympanum with internal ears). Out of these, eyes and internal ears are well-organised structures and the rest are cellular aggregations around nerve endings. Eyes in a frog are a pair of spherical structures situated in the orbit in skull These are simple eyes (possessing only one unit). External ear is absent in frogs and only tympanum can be seen externally The ear is an organ of hearing as well as balancing (equilibrium). Frogs have well organised male and female reproductive systems Male reproductive organs consist of a pair of yellowish ovoid testes (Figure 7.3), which are found adhered to the upper part of kidneys by a double fold of peritoneum called mesorchium. Vasa efferentia are 10-12 in number that arise from testes. They enter the kidneys on their side and open into Bidder’s
NCERT LINE BY LINE QUESTIONS
39. Assertion (A): Frogs are ammonotelic
Reason (R): Their nitrogenous waste is excreted primarily as ammonia through the cloaca
(a) and R true, R explains A
(b) A and R true, R doesn’t explain A
(c) A true, R false
(d) Both false A
40. Match the following
Gland Function
A. Pituitary 1. Secretes sex hormones
B Thyroid 2 Stress and emergency
hormone
C. Gonads 3. Regulates metabolism
D. Adrenals 4. Master gland regulating
other glands
(a) A-3, B-2, C-1, D-4
(b) A-2, B-1, C-4, D-3
(c) A-4, B-3, C-1, D-2
(d) A-1, B-4, C-2, D-3
41. In frogs, the brain is enclosed in a skull cavity called the cranium True \False
42. Mark the correct option after reading all the statements.
1.The frog’s brain consists of forebrain, midbrain, hindbrain
2 Cranial nerves arise from the spinal cord
3.Brain exits skull through foramen magnum.
4.Nerves of autonomic system include sympathetic and parasympathetic
(a) 1, 3 and 4 only
(b) 2 and 4 only
(c) All are correct (d) 1 and 4 only
43. The brain of frog gives rise to pairs of cranial nerves
(a) 8 (b) 10 (c) 12 (d) 14
44. In male frogs vasa efferentia are in number which arise from .
45. Match the following
Sense Organ Stimulus Detected
A Sensory papillae 1 Gustation
B. Nasal epithelium 2. Touch
C. Tympanum 3. Smell
D. Taste buds 4. Sound and
equillibrium
(a) A-2, B-3, C-4, D-1
(b) A-4, B-1, C-2, D-3
(c) A-1, B-2, C-3, D-4
(d) A-1, B-3, C-2, D-4
46. Bidder’s canal is present in the female frog’s reproductive system (True\False)
47. Choose the correct option from the following:
1.Frog’s testes are attached to kidneys.
2.Vasa efferentia emerge from testes and open into Bidder’s canal
3.Ovaries in females open into the cloaca via oviducts.
4.Ureters in males serve both reproductive and excretory functions
Which are correct?
(a) 1, 2, 3 and 4 (b) 1 and 3 only (c) 2, 3 and 4 only (d) 1, 3 and 4 only
48. Which of the following is a functional similarity in male and female frogs?
(a) Presence of ovary and testes
(b) Cloacal aperture as the common opening
(c) Bidder’s canal in both sexes
(d) Ureter acting as reproductive duct in both
49. Each testis is attached to the upper part of the kidney by a fold of peritoneum called the .
(a) cloaca
(b) ureter
(c) mesorchium
(d) Bidder’s duct
canal. Finally it communicates with the urinogenital duct that comes out of the kidneys and opens into the cloaca. The cloaca is a small, median chamber that is used to pass faecal matter, urine and sperms to the exterior. The female reproductive organs include a pair of ovaries (Figure 7 4) The ovaries are situated near kidneys and there is no functional connection with kidneys. A pair of oviduct arising from the ovaries opens into the cloaca separately A mature female can lay 2500 to 3000 ova at a time Fertilisation is external and takes place in water. Development involves a larval stage called tadpole. Tadpole undergoes metamorphosis to form the adult.
Frogs are beneficial for mankind because they eat insects and protect the crop. Frogs maintain ecological balance because these serve as an important link of food chain and food web in the ecosystem. In some countries the muscular legs of frog are used as food by man.
S U M M A R Y
Cells, tissues, organs and organ systems split up the work in a way that ensures the survival of the body as a whole and exhibit division of labour. A tissue is defined as group of cells along with intercellular substances performing one or more functions in the body Epithelia are sheet like tissues lining the body’s surface and its cavities, ducts and tubes. Epithelia have one free surface facing a body fluid or the outside environment. Their cells are structurally and functionally connected at junctions. The Indian bullfrog, Rana tigrina, is the common frog found in India. Body is covered by skin. Mucous glands are present in the skin which is highly vascularised and helps in respiration in water and on land Body is divisible into head and trunk. A muscular tongue is present, which is bilobed at the tip and is used in capturing the prey. The alimentary canal consists of oesophagous, stomach, intestine and rectum, which open into the cloaca The main digestive glands are liver and pancreas. It can respire in water through skin and through lungs on land. Circulatory system is closed with single circulation RBCs are nucleated Nervous system is organised into central, peripheral and autonomic. The organs of urinogenital system are kidneys and urinogenital ducts, which open into the cloaca. The male reproductive organ is a pair of testes The female reproductive organ is a pair of ovaries A female lays 2500-3000 ova at a time. The fertilisation and development are external. The eggs hatch into tadpoles, which metamorphose into frogs.
EXERCISES
1.Draw a neat diagram of digestive system of frog.
2 Mention the function of the Ureters in frog
DELETED TOPICS
7.1 Animal Tissues
In the preceding chapters you came across a large variety of organisms, both unicellular and multicellular, of the animal kingdom. In unicellular organisms, all functions like digestion, respiration and reproduction are performed by a single cell In the complex body of multicellular animals the same basic functions are carried out by different groups of cells in a well organised manner. The body of a simple organism like Hydra is made of different types of cells and the number of cells in each type can be in thousands The human body is composed of billions of cells to perform various functions. How do these cells in the body work together? In multicellular animals, a group of similar cells alongwith intercellular substances perform a specific function. Such an organisation is called tissue
You may be surprised to know that all complex animals consist of only four basic types of tissues
These tissues are organised in specific proportion and pattern to form an organ like stomach, lung, heart and kidney. When two or more organs perform a common function by their physical and/or chemical interaction, they together form organ system, e g , digestive system, respiratory system, etc. Cells, tissues, organs and organ systems split up the work in a way that exhibits division of labour and contribute to the survival of the body as a whole.
The structure of the cells vary according to their function. Therefore, the tissues are different and are broadly classified into four types : (i) Epithelial, (ii) Connective, (iii) Muscular and (iv) Neural
7.1.1 Epithelial Tissue
We commonly refer to an epithelial tissue as epithelium (pl : epithelia) This tissue has a free surface, which faces either a body fluid or the outside environment and thus provides a covering or a lining for some part of the body. The cells are compactly packed with little intercellular matrix. There are two types of epithelial tissues namely simple epithelium and compound epithelium
Simple epithelium is composed of a single layer of cells and functions as a lining for body cavities, ducts, and tubes. The compound epithelium consists of two or more cell layers and has protective function as it does in our skin
On the basis of structural modification of the cells, simple epithelium is further divided into three types These are (i) Squamous, (ii) Cuboidal, (iii) Columnar (Figure 7 1)
The squamous epithelium is made of a single thin layer of flattened cells with irregular boundaries. They are found in the walls of blood vessels and air sacs of lungs and are involved in functions like forming a diffusion boundary. The cuboidal epithelium is composed of a single layer of cube-like cells. This is commonly found in ducts of glands and tubular parts of nephrons in kidneys and its main functions are secretion and absorption The epithelium of proximal convoluted tubule (PCT) of nephron in the kidney has microvilli. The columnar epithelium is composed of a single layer of tall and slender cells. Their nuclei are located at the base. Free surface may have microvilli. They are found in the lining of stomach and intestine and help in secretion and absorption If the columnar or cuboidal cells bear cilia on their free surface they are called ciliated epithelium (Figure 7.1d). Their function is to move particles or mucus in a specific direction over the epithelium. They are mainly present in the inner surface of hollow organs like bronchioles and fallopian tubes
Some of the columnar or cuboidal cells get specialised for secretion and are called glandular epithelium (Figure 7.2). They are mainly of two types: unicellular, consisting of isolated glandular cells (goblet cells of the alimentary canal), and multicellular, consisting of cluster of cells (salivary gland) On the basis of the mode of pouring of their secretions, glands are divided into two categories namely exocrine and endocrine glands. Exocrine glands secrete mucus, saliva, earwax, oil, milk, digestive enzymes and other cell products. These products are released through ducts or tubes In contrast, endocrine glands do not have ducts Their products called hormones are secreted directly into the fluid bathing the gland.
Compound epithelium is made of more than one layer (multi-layered) of cells and thus has a limited role in secretion and absorption (Figure 7.3). Their main function is to provide protection against chemical and mechanical stresses. They cover the dry surface of the skin, the moist surface of buccal cavity, pharynx, inner lining of ducts of salivary glands and of pancreatic ducts
All cells in epithelium are held together with little intercellular material
In nearly all animal tissues, specialised junctions provide both structural and functional links between its individual cells. Three types of cell junctions are found in the epithelium and other tissues These are called as tight, adhering and gap junctions. Tight junctions help to stop substances from leaking across a tissue. Adhering junctions perform cementing to keep neighbouring cells together Gap junctions facilitate the cells to communicate with each other by connecting the cytoplasm of adjoining cells, for rapid transfer of ions, small molecules and sometimes big molecules
7.1.2 Connective Tissue
Connective tissues are most abundant and widely distributed in the body of complex animals They are named connective tissues because of their special function of linking and supporting other tissues/organs of the body. They range from soft connective tissues to specialised types, which
NCERT LINE BY LINE QUESTIONS
50.Assertion (A): In multicellular animals, a group of similar cells together performing a specific function is called tissue.
Reason (R): Tissues are randomly organized in the body to perform general functions
(a). Both A and R are true, and R is the correct explanation
(b) Both A and R are true, but R is not the correct explanation
(c). A is true, but R is false
(d) A is false, but R is true
51. Match the Column Column A Column B
A. Cell 1. n Group of organs working
B. Tissue.
54. In the human body, tissues are organized:
a. In random fashion across organs
b. In specific patterns and proportions to form organs
c. Without cellular specialization
d. Only in neural structures
55. Stomach, heart, lungs and kidney are examples of formed by specific arrangement of tissues
56. Assertion (A): Cells, tissues, organs and systems function together to support life.
Reason (R): This structural organization shows coordination and division of labour.
2. Basic unit of structure and
C Organ 3 Group of similar cells with
togeteher function specific function tissues
D. Organ 4. Formed from organized system
(a) A-2, B-1, C-4, D-3
(b) A-1, B-2, C-4, D-3
(c) A-4, B-3, C-2, D-1
(d) A-2, B-3 ,C-4, D-1
52 True / False
a. Hydra is composed of billions of cells
b. Tissues are present even in unicellular organisms
c. Digestive system is an example of an organ system
d Organ systems exhibit division of labour
53. Assertion (A): Tissues, organs, and systems perform isolated functions in animals.
Reason (R): This allows independent survival of each organ
(a).Both A and R are true, and R is the correct explanation
(b) Both A and R are true, but R is not the correct explanation
(c).A is true, but R is false
(d) A is false, but R is true
(a) Both A and R are true, and R is the correct explanation (b).Both A and R are true, but R is not the correct explanation
(c) A is true, but R is false (d).A is false, but R is true
57. Match the Column Column A Column B
A Lung 1 Organ
B Respiratory system 2 Organelle
C. Epithelial cells 3. Tissue
D. Mitochondrion 4. Organ system
(a) A-2, B-1, C-4, D-3 (b) A-1, B-2, C-4, D-3
(c) A-4, B-3, C-2, D-1 (d) A-1, B-4, C-3, D-2
58. Fill in the Blank
When two or more organs perform a common function, they form an .
59 Which of the following best explains the term "division of labour" in multicellular organisms?
(a).Cells switch randomly between functions (b). Different cells specialize for specific tasks (c) All cells perform all functions together (d). Organelles perform multicellular tasks
60. True / False
(a) Neural tissue helps form the nervous system (b) Organ systems arise from disorganized cell masses
(c) Systems work in isolation to perform body functions
(d) Tissues in animals are only three types
NCERT LINE BY LINE QUESTIONS
61. Match the Column Column A Column B
A. Epithelial 1.Support and transport
B. Connective 2. Covering and protection
C Muscular 3 Impulse conduction
D. Neural 4. Movement
(a) A-1, B-2, C-4, D-3
(b) A-2, B-1, C-4, D-3
(c) A-4, B-3, C-2, D-1
(d) A-3, B-4, C-1, D-2
62. Assertion (A): Simple epithelium is composed of a single layer of cells
Reason (R): It is primarily involved in protection in high-friction areas like skin.
(a) Both A and R are true, and R is the correct explanation
(b) Both A and R are true, but R is not the correct explanation
(c) A is true, but R is false
(d) A is false, but R is true
63. Epithelial tissue has a surface which faces either a body fluid or the outside environment
64. Mark the incorrect statements from the following:
(a) Flattened cells with irregular boundaries are squamous epithelium
(b) Cuboidal are cube shaped cells can have microvilli as well as no surface attachments.
(c) Tall slender cells, may have microvilli can also have glandular cells are cubodial epithelium.
(d) Cube-like cells, found in kidney tubules
65. Answer the True / False
(a) Compound epithelium is made of one cell layer
(b) Simple epithelium lines ducts, body cavities and tubules
(c) Cuboidal cells are flat and wide
(d) Ciliated epithelium helps in moving mucus
66. The lining of stomach and intestine contains epithelium specialized for secretion and absorption.
69. When epithelial cells bear cilia on their free surface, they are known as glandular epithelium. (True/False)
70. Assertion (A): Columnar epithelium contains nuclei near the apical surface.
Reason (R): It facilitates filtration in glomeruli (a.)Both A and R are true, and R is the correct explanation
(b) A is true, but R is false (c) A is false, but R is true (d). Both A and R are false
71. Epithelial tissue cells are compactly packed with very little .
72. Assertion (A): Compound epithelium is more involved in secretion and absorption than simple epithelium.
Reason (R): It is composed of multiple layers of cells.
(a) Both A and R are true, and R is the correct explanation
(b) Both A and R are true, but R is not the correct explanation (c) A is false, but R is true (d) Both A and R are false
73. The epithelium of proximal convoluted tubule (PCT) in nephron has to aid in reabsorption.
NCERT LINE BY LINE QUESTIONS
74. The epithelium best suited for lining air sacs for diffusion is
75. Assertion (A): Glandular epithelium includes only cuboidal cells specialized for secretion.
Reason (R): Only cuboidal cells can form glands
(a) Both A and R are true, and R is the correct explanation
(b) Both A and R are true, but R is not the correct explanation
(c) A is true, but R is false
(d) Both A and R are false
76. Goblet cells of the alimentary canal are an example of .
77. Match the following Column A Column B
A. Unicellular gland 1. Secretes via ducts
B Multicellular gland 2 Salivary gland
C. Exocrine gland 3. Goblet cells
D.Endocrine gland 4. Ductless, secretes
(a) A-2, B-1, C-4, D-3
(b) A-3, B-2, C-1, D-4
(c) A-4, B-3, C-2, D-1
(d) A-3, B-4, C-1, D-2
78. True / False –
(a) Endocrine glands secrete enzymes via ducts
(b) Exocrine glands include sweat and salivary glands
(c) Endocrine products are hormones
(d) Unicellular glands are always endocrine
79. Assertion (A): Endocrine glands are ductless.
80. Compound epithelium can be found in:
(a) Alveoli of lungs
(b) PCT of kidney
(c) Moist surface of buccal cavity
(d) Intestinal lining
81. junctions help prevent leakage of substances across tissues.
82. Assertion (A): Gap junctions connect cytoplasm of adjacent cells.
Reason (R): They prevent passage of molecules between cells.
(a) Both A and R are true, and R is the correct explanation
(b) A is true, but R is false
(c) Both A and R are false
(d) A is false, but R is true
83. True / False
(a) Tight junctions help leak-proof epithelial layers
(b) Adhering junctions cement cells together
(c) Gap junctions block communication
(d) All cell junctions are found only in connective tissue
84.Gap junctions allow passage of , and sometimes big molecules between cells.
85. epithelium lines the inner ducts of salivary and pancreatic glands and offers protection.
86. Compound epithelium is mainly involved in , not absorption or secretion hormones
Reason (R): Their secretions are released into ducts for excretion
(a) Both A and R are true, and R is the correct explanation
(b) A is true, but R is false
(c) Both A and R are false
(d) A is false, but R is true
include cartilage, bone, adipose, and blood. In all connective tissues except blood, the cells secrete fibres of structural proteins called collagen or elastin The fibres provide strength, elasticity and flexibility to the tissue. These cells also secrete modified polysaccharides, which accumulate between cells and fibres and act as matrix (ground substance). Connective tissues are classified into three types: (i) Loose connective tissue,(ii) Dense connective tissue and (iii) Specialised connective tissue.
Loose connective tissue has cells and fibres loosely arranged in a semifluid ground substance, for example, areolar tissue present beneath the skin (Figure 7.4). Often it serves as a support framework for epithelium. It contains fibroblasts (cells that produce and secrete fibres), macrophages and mast cells. Adipose tissue is another type of loose connective tissue located mainly beneath the skin. The cells of this tissue are specialised to store fats The excess of nutrients which are not used immediately are converted into fats and are stored in this tissue.
Fibres and fibroblasts are compactly packed in the dense connective tissues. Orientation of fibres show a regular or irregular pattern and are called dense regular and dense irregular tissues. In the dense regular connective tissues, the collagen fibres are present in rows between many parallel bundles of fibres. Tendons, whichattach skeletal muscles to bones and ligaments which attach one bone to another are examples of this tissue Dense irregular connective tissue has fibroblasts and many fibres (mostly collagen) that are oriented differently (Figure 7.5). This tissue is present in the skin. Cartilage, bones and blood are various types of specialised connective tissues
The intercellular material of cartilage is solid and pliable and resists compression. Cells of this tissue (chondrocytes) are enclosed in small cavities within the matrix secreted by them (Figure 7 6a) Most of the cartilages in vertebrate embryos are replaced by bones in adults Cartilage is present in the tip of nose, outer ear joints, between adjacent bones of the vertebral column, limbs and hands in adults. Bones have a hard and non-pliable ground substance rich in calcium salts and collagen fibres which give bone its strength (Figure 7 6b) It is the main tissue that provides structural frame to the body. Bones support and protect softer tissues and organs.
94. Collagen fibres are present in rows between many bundles in connective tissue.
95. True / False
(a) Tendons are made of dense irregular connective tissue –
(b) Dense regular tissue attaches muscles to bones
(c) Dense irregular tissue is found in dermis
(d) Fibres in dense regular tissue run in multiple directions
96. Adipose tissue is mainly found between the bones and the muscles. (True/False)
97 .The major difference between dense regular and dense irregular tissue is:
(a) Presence of fibroblasts
(b) Direction of fibre arrangement
(c) Ground substance composition
(d) Absence of matrix
98. Match the Column Column A Column B A Tendon 1 Dense regular
B. Dermis 2. Dense irregular
C Subcutaneous fat 3 Adipose tissue
D. Epithelium support 4. Areolar tissue
(a) A-2, B-1, C-4, D-3
(b) A-1, B-2, C-4, D-3
(c) A-4, B-3, C-2, D-1
(d) A-3, B-4, C-1, D-2
99. The fibres in connective tissue provide strength, flexibility and . connective tissue connective tissue
RBC
WBC Platelets ( a ) ( b ) ( c )
F i g u r e 7
The bone cells (osteocytes) are present in the spaces called lacunae. Limb bones, such as the long bones of the legs, serve weight-bearing functions They also interact with skeletal muscles attached to them to bring about movements. The bone marrow in some bones is the site of production of blood cells.
Blood is a fluid connective tissue containing plasma, red blood cells (RBC), white blood cells (WBC) and platelets (Figure 7.6c). It is the main circulating fluid that helps in the transport of various substances. You will learn more about blood in Chapters 17 and 18
7.1.3 Muscle Tissue
Each muscle is made of many long, cylindrical fibres arranged in parallel arrays. These fibres are composed of numerous fine fibrils, called myofibrils. Muscle fibres contract (shorten) in response to stimulation, then relax (lengthen) and return to their uncontracted state in a coordinated fashion. Their action moves the body to adjust to the changes in the environment and to maintain the positions of the various parts of the body In general, muscles play an active role in all the movements of the body. Muscles are of three types, skeletal, smooth, and cardiac.
Skeletal muscle tissue is closely attached to skeletal bones In a typical muscle such as the biceps, striated (striped) skeletal muscle fibres are bundled together in a parallel fashion (Figure 7.7a). A sheath of tough connective tissue encloses several bundles of muscle fibres (You will learn more about this in Chapter 20).
(b) Bone (c) Blood
The smooth muscle fibres taper at both ends (fusiform) and do not show striations (Figure 7.7b). Cell junctions hold them together and they are bundled together in a connective tissue sheath The wall of internal organs such as the blood vessels, stomach and intestine contains this type of muscle tissue. Smooth muscles are ‘involuntary’ as their functioning cannot be directly controlled We usually are not able to make it contract merely by thinking about it as we can do with skeletal muscles.
Cardiac muscle tissue is a contractile tissue present only in the heart Cell junctions fuse the plasma membranes of cardiac muscle cells and make them stick together (Figure 7.7c). Communication junctions (intercalated discs) at some fusion points allow the cells to contract as a unit, i.e., when one cell receives a signal to contract, its neighbours are also stimulated to contract.
7.1.4
Neural Tissue
Neural tissue exerts the greatest control over the body’s responsiveness to changing conditions. Neurons, the unit of neural system are excitable cells (Figure 7 8) The neuroglial cell which constitute the rest of the neural system protect and support neurons. Neuroglia make up more than one- half the volume of neural tissue in our body When a neuron is suitably stimulated, an electrical disturbance is generated which swiftly travels along its plasma
7.4 COCKROACH
Cockroaches are brown or black bodied animals that are included in class Insecta of Phylum Arthropoda. Bright yellow, red and green coloured cockroaches have also been reported in tropical regions. Their size ranges from ¼ inches to 3 inches (0 6-7 6 cm long antenna, legs and flat extension of the upper body conceals head. They are nocturnal omnivores that live in da throughout the world They have become residents of hum and thus are serious pests and vectors of several diseases.
7.4.1
Morphology
The adults of the common species of cockroach, Periplaneta are about 34-53 mm long with wings that extend beyond th abdomen in males. The body of the cockroach is segm divisible into three distinct regions – head, thorax and abdomen (Figure 7.14). The entire body is covered by a hard chitinous exoskeleton (brown in colour). In each segment, exoskeleton has hardened plates called sclerites (tergites dorsally and sternites ventrally) that are joined to each other by a thin and flexible articular membrane (arthrodial membrane).
Reason (R): They constitute more than half the volume of neural tissue.
a. Both A and R are true, and R is the correct explanation
b. A is true, but R is false
c. A is false, but R is true
d Both A and R are false
117. The central part of a neuron that contains the nucleus is called
Answer: cell body or cyton
15. Smooth muscle is commonly found in:
a. Cardiac tissue
b Biceps
c. Blood vessels
d. Vertebral column neurons from cell body unstriated multinucleated intercalated discs
NCERT LINE BY LINE QUESTIONS
118. Cockroaches belong to class of Phylum Arthropoda
119.True/False: Cockroaches are strictly herbivorous and active during daytime.
120. Assertion (A): Cockroaches are considered serious pests.
Reason (R): They are known to transmit several plant diseases.
(a) Both A and R true, R explains A
(b) Both A and R true, R does not explain A
(c) A true, R false
(d) A false, R true
121. Which of the following are true about cockroaches?
1.Found in class Insecta of Arthropoda.
2.Range in size from 0.6 cm to 7.6 cm.
3.Found only in tropical forests.
4 Nocturnal omnivores
(a) 1, 2, 4
(b) 2, 3, 4
(c) 1, 3, 4
(d) All are correct
122. The species Periplaneta americana is commonly studied in cockroach biology and measures about mm in length
(a) 20–40
(b) 25–60
(c) 34–53
(d) 40–70
123. True/False: Cockroach wings do not extend beyond the tip of the abdomen
124. Which of the following correctly matches the part with function?
(a) Pronotum – sensory structure
(b) Anal cerci – reproductive function
(c) Filiform antennae – sensory perception
(d) Mesothoracic leg – located in head region
125. Match the Following Column A Column B
A. Head 1. Hard, chitinous brown
covering
B. Thorax 2. Contains compound eyes,
C. Abdomen 3. Posterior body segment
D Exoskeleton 4 Prothorax, mesothorax,
antennae ,metathorax
(a) A–3, B–2, C–1, D–4
(b) A–2, B–1, C–3, D–4
(c) A–1, B–3, C–2, D–4
(d) A–2, B–4, C–3, D–1
126.
Assertion (A): Cockroach’s exoskeleton has hardened plates called sclerites.
Reason (R): These sclerites are joined by a rigid, immobile membrane.
(a) Both A and R true, R explains A
(b) Both A and R true, but R does not explain A
(c) A true, R false
(d) A false, R true
127. In cockroach, the dorsal and ventral hardened plates of each segment are called and respectively
128. Arrange the following exoskeletal segments from anterior to posterior based on external cockroach anatomy:
1 Mesothorax
2. Pronotum
3. Head capsule
4 Abdomen
5 Metathorax
(a) 3 2 1 5 4
(b) 2 1 3 4 5
(c) 1 3 2 5 4
(d) 1 2 4 3 5
Head is triangular in shape and lies anteriorly at right angles to the longitudinal body axis. It is formed by the fusion of six segments and shows great mobility in all directions due to flexible neck (Figure 7.15). The head capsule bears a pair of compound eyes. A pair of thread like antennae arise from membranous sockets lying in front of eyes. Antennae have sensory receptors that help in monitoring the environment Anterior end of the head bears appendages forming biting and chewing type of mouth parts. The mouthparts consisting of a labrum (upper lip), a pair of mandibles, a pair of maxillae and a labium (lower lip). A median flexible lobe, acting as tongue (hypopharynx), lies within the cavity enclosed by the mouthparts (Figure 7 15b) Thorax consists of three parts – prothorax, mesothorax and metathorax. The head is connected with thorax by a short extension of the prothorax known as the neck. Each thoracic segment bears a pair of walking legs. The first pair of wings arises from mesothorax and the second pair from metathorax Forewings (mesothoracic) called tegmina are opaque dark and leathery and cover the hind wings when at rest. The hind wings are transparent, membranous and are used in flight. The abdomen in both males and females consists of 10 segments In females, the 7th sternum is boat shaped and together with the 8th and 9th sterna forms a brood or genital pouch whose anterior part contains female gonopore, spermathecal pores and collateral glands. In males, genital pouch or chamber lies at the hind end of abdomen bounded dorsally by 9th and 10th terga and ventrally by the 9th sternum. It contains dorsal anus, ventral male genital pore and gonapophysis. Males bear a pair of short, thread- like anal styles which are absent in females. In both sexes, the 10th segment bears a pair of jointed filamentous structures called anal cerci.
7.4.2
Anatomy
The alimentary canal present in the body cavity is divided into three regions: foregut, midgut and hindgut (Figure 7.16). The mouth opens into a short tubular pharynx, leading to a narrow tubular passage called oesophagus This in turn opens into a sac like structure called crop used for storing of food. The crop is followed by gizzard or proventriculus. It has an outer layer of thick circular muscles and thick inner cuticle forming six highly chitinous plate called teeth. Gizzard helps in grinding the food particles The entire foregut is lined by cuticle A ring of 6-8 blind tubules called hepatic or gastric caeca is present at the junction of foregut and midgut, which secrete digestive juice. At the junction of midgut and hindgut is present another ring of 100-150 yellow coloured thin filamentous Malpighian tubules They help in removal of excretory products from haemolymph The hindgut is broader than midgut and is differentiated into ileum, colon and rectum. The rectum opens out through anus.
Figure 7.15 Head region of cockroach : (a) parts of head region (b) mouth parts
NCERT LINE BY LINE QUESTIONS
129. True/False
Cockroach head is immobile and fused rigidly to the thorax.
130. Which of the following are true about cockroach antennae?
1.Arise from membranous sockets
2 Located behind compound eyes
3.Thread-like, sensory in function
4.Involved in food grinding
(a) 1, 2, 3
(b) 1, 3
(c) Only 3
(d) All
131. In cockroach head, which structure acts as lower lip?
(a) Maxilla
(b) Labium
(c) Hypopharynx
(d) Labrum
132. A pair of and a median form the complete set of cockroach mouthparts.
133. Which statements are true for the thorax of cockroach?
1.Consists of prothorax, mesothorax, metathorax
2.First pair of wings arises from prothorax
3.Each thoracic segment bears walking legs
4 Tegmina arise from mesothorax
(a) 1, 3, 4 (b) 1, 2, 3 (c) 2, 3, 4 (d) All
134.The leathery, opaque forewings in cockroach are known as .
135. True/False
Tegmina are transparent, membranous wings used for flight.
136. The head connects to the thorax via a short extension of the known as the
137.Which are correct regarding cockroach abdomen?
1. 10 segments in both sexes
2 7th sternum in females is boat-shaped
3. 10th segment bears anal cerci in both sexes
4. Anal styles found in both sexes
(a) 1, 2, 3 (b) 2, 3, 4 (c) 1, 3 (d) All
138. A: Anal styles are found only in male cockroaches
R: Both sexes have anal cerci but only males possess paired anal styles.
(a) Both A and R true; R explains A (b) Both A and R true; R does not explain A (c) A true, R false
(d) A false, R true
139. In females, the genital pouch is formed by the sterna.
(a) 6th and 7 (b) 7th, 8th and 9th th (c) 8th and 10 (d) 9th and 10th th
140. Which of the following are reproductive openings in female cockroach?
1 Gonopore
2.Spermathecal pores
3.Collateral glands
4 Anal cerci
(a) 1, 2, 3 (b) 2, 3, 4 (c) 1, 3, 4 (d) All
141. True/False
Genital pouch in male lies between 8th and 10th tergites dorsally and 9th sternum ventrally.
142. Match the Following
A. Prothorax 1. Bears neck, walking legs
B. Mesothorax 2. Bears tegmina
C Metathorax 3 Bears hindwings
(a) A-1, B-2, C-3
(b) A-2, B-1, C-3
(c) A-1, B-3, C-2
(d) A-3, B-2, C-1
7.16 Alimentary canal of
7.17 Open circulatory system
Blood vascular system of cockroach is an open type (Figure 7 17) Blood vessels are poorly developed and open into space (haemocoel). Visceral organs located in the haemocoel are bathed in blood (haemolymph). The haemolymph is composed of colourless plasma and haemocytes. Heart of cockroach consists of elongated muscular tube lying along mid dorsal line of thorax and abdomen. It is differentiated into funnel shaped chambers with ostia on either side Blood from sinuses enter heart through ostia and is pumped anteriorly to sinuses again.
The respiratory system consists of a network of trachea, that open through 10 pairs of small holes called spiracles present on the lateral side of the body Thin branching tubes (tracheal tubes subdivided into tracheoles) carry oxygen from the air to all the parts. The opening of the spiracles is regulated by the sphincters. Exchange of gases take place at the tracheoles by diffusion.
Excretion is performed by Malpighian tubules. Each tubule is lined by glandular and ciliated cells. They absorb nitrogenous waste products and convert them into uric acid which is excreted out through the hindgut. Therefore, this insect is called uricotelic. In addition, the fat body, nephrocytes and urecose glands also help in excretion.
The nervous system of cockroach consists of a series of fused, segmentally arranged ganglia joined by paired longitudinal connectives on the ventral side Three ganglia lie in the thorax, and six in the abdomen. The nervous system of cockroach is spread throughout the body. The head holds a bit of a nervous system while the rest is situated along the ventral (belly-side) part of its body. So, now you understand that if the head of a cockroach is cut off, it will still live for as long as one week In the head region, the brain is represented by supra-oesophageal ganglion which supplies nerves to antennae and compound eyes. In cockroach, the sense organs are antennae, eyes, maxillary palps, labial palps, anal cerci, etc The compound eyes are situated at the dorsal surface of the head Each eye consists of about 2000 hexagonal ommatidia (sing.: ommatidium). With the help of several ommatidia, a cockroach can receive several images of an object. This kind of vision is known as mosaic vision with more sensitivity but less resolution, being common during night (hence called nocturnal vision).
Cockroaches are dioecious and both sexes have well developed reproductive organs (Figure 7.18). Male reproductive system consists of a pair of testes one lying on each lateral side in the 4th -6th abdominal segments From each testis arises a thin vas deferens, which opens into ejaculatory duct through seminal vesicle.
Figure
cockroach
Figure
of cockroach
NCERT LINE BY LINE QUESTIONS
143.The alimentary canal of cockroach is divided into 3 regions
144. True/False
The gizzard has thin inner cuticle and is poorly muscularized.
145. Match the Following –
Column A
Column B
A Crop 1 Grinding of food
B. Gizzard 2. Storage of food
C. Hepatic caeca 3. Connects mouth to
149. Arrange the following in the path of food movement:
1 Pharynx
2. Crop
3. Gizzard
4. Oesophagus
150. Rectum of cockroach is broader than midgut and opens to the outside. (True/false)
D. Pharynx 4. Secretes digestive
(a) A-1, B-2, C-4, D-3
(b) A-2, B-1, C-4, D-3
(c) A-4, B-3, C-2, D-1
(d) A-3, B-4, C-1, D-2
146. Assertion & Reason –
oesophagus juice
A: Gizzard in cockroach performs mechanical digestion.
R: Its inner lining contains 6 chitinous teeth.
(a) Both A & R true; R explains A
(b) Both A & R true; R doesn't explain A
(c) A true, R false
(d) A false, R true
147. The is a ring of 100–150 yellow thread-like structures found at the junction of midgut and hindgut.
148. Which of the following are correct about cockroach digestion?
1. Hepatic caeca secrete digestive enzymes
2. Midgut is lined with thin cuticle
3 Crop stores food
4. Gizzard secretes enzymes
(a)2, 3, 4
(b) 1, 3, 4
(c) 1, 2, 3
(d) All
151. Blood vessels in cockroach are poorly developed and open into spaces called .
154. Which of the following are true about cockroach heart?
1. Located on dorsal side
2 Funnel-shaped chambers with ostia
3. Blood flows anteriorly
4. Blood is pumped into closed vessels
(a) 1, 2, 3 (b) 2, 3, 4 (c) 1, 3, 4 (d) All
155. Spiracles in cockroach are:
(a) Paired excretory glands
(b) Digestive openings
(c) Small pores on lateral body wall (d) Tubular air sacs inside heart freely chambers
C o c o a c e s a e d o e c o u s a d b o t s e e s a e e d e e o p e d e p o d u c t e o g a s ( g u e
7 . 1 8 ) . M a l e r e p r o d u c t i v e s y s t e m c o n s i s t s o f a p a i r o f t e s t e s o n e l y i n g o n e a c h l a t e r a l s i d e i n
t h e 4 t h - 6 t h a b d o m i n a l s e g m e n t s F r o m e a c h t e s t i s a r i s e s a t h i n v a s d e f e r e n s , w h i c h o p e n s
i n t o e j a c u l a t o r y d u c t t h r o u g h s e m i n a l v e s i c l e . T h e e j a c u l a t o r y d u c t o p e n s i n t o m a l e g o n o p o r e
s i t u a t e d v e n t r a l t o a n u s . A c h a r a c t e r i s t i c m u s h r o o m - s h a p e d g l a n d i s p r e s e n t i n t h e 6 t h - 7 t h
a b d o m i n a l s e g m e n t s w h i c h f u n c t i o n s a s a n a c c e s s o r y r e p r o d u c t i v e g l a n d T h e e x t e r n a l
g e n i t a l i a a r e r e p r e s e n t e d b y m a l e g o n a p o p h y s i s o r p h a l l o m e r e ( c h i t i n o u s a s y m m e t r i c a l
s t r u c t u r e s , s u r r o u n d i n g t h e m a l e g o n o p o r e ) . T h e s p e r m s a r e s t o r e d i n t h e s e m i n a l v e s i c l e s
a n d a r e g l u e d t o g e t h e r i n t h e f o r m o f b u n d l e s c a l l e d s p e r m a t o p h o r e s w h i c h a r e d i s c h a r g e d
d u r i n g c o p u l a t i o n . T h e f e m a l e r e p r o d u c t i v e s y s y t e m c o n s i s t s o f t w o l a r g e o v a r i e s , l y i n g
l a t e r a l l y i n t h e 2 n d – 6 t h a b d o m i n a l s e g m e n t s . E a c h o v a r y i s f o r m e d o f a g r o u p o f e i g h t
o v a r i a n t u b u l e s o r o v a r i o l e s , c o n t a i n i n g a
Sperms are transferred through spermatophores Their fertilised eggs are encased in capsules called oothecae. Ootheca is a dark reddish to blackish brown capsule, about 3/8" (8 mm) long. They are dropped or glued to a suitable surface, usually in a crack or crevice of high relative humidity near a food source On an average, females produce 9-10 oothecae, each containing 14-16 eggs The development of P. americana is paurometabolous, meaning there is development through nymphal stage. The nymphs look very much like adults. The nymph grows by moulting about 13 times to reach the adult form The next to last nymphal stage has wing pads but only adult cockroaches have wings.
Many species of cockroaches are wild and are of no known economic importance yet. A few species thrive in and around human habitat. They are pests because they spoil food and contaminate it with their smelly excreta They can transmit a variety of bacterial diseases by contaminating food material.
Reproductive
NCERT LINE BY LINE QUESTIONS
156. Excretion in cockroach is performed by and the nitrogenous waste excreted is .
157. Excretion in cockroaches are done by
(A) Malpighian tubules
(B) Fat Body
(C) Nephrocytes
(D) Urecose gland
Choose the correct options from the below:
(a) All four
(b) A & B only
(c) B & C only
(d) B, A, and C
158. Which of the following are true about cockroach nervous system?
1. Has ventral nerve cord with ganglia
2 3 ganglia in thorax, 6 in abdomen
3. Remains functional even after head is removed
4 Head alone contains complete nervous system
(a) 2, 3, 4
(b) 1, 3, 4
(c) 1, 2, 3
(d) All
159. True/False
Cockroach will die immediately if its head is cut off
160. The supra-oesophageal ganglion in cockroach sends nerves to and .
(a) eyes, ovary
(b) cerci, wings
(c) antennae, compound eyes
(d) mouth, wings
161. Each compound eye of cockroach has about hexagonal ommatidia.
162. Cockroach compound eye provides vision which is common during night.
163. Which are true about cockroach male reproductive system?
1. Testes are paired, lateral, lie in 4th–6th abdominal segments
2 Mushroom gland is accessory gland
3. Spermatophores form in seminal vesicles
4. Genital pore lies dorsally
(a) 1, 2, 3 (b) 1, 3, 4 (c) 2, 3, 4 (d) All
164. A: Gonapophysis surround the female genital chamber.
R: They are keratinous and assist in egg-laying.
(a) Both A and R true, R explains A (b) Both A and R true, R does not explain A (c) A true, R false (d) A false, R true
R: They transmit diseases by contaminating food (a) Both true, R explains A (b) Both true, R doesn't explain A (c) A true, R false (d) Both false
NCERT LINE BY LINE QUESTIONS CRUX OF NCERT
A researcher is comparing structural and functional aspects of Pheretima posthuma, Periplaneta americana, Rana tigrina, and human tissue samples under the microscope and via dissection. Based on her findings, evaluate the following observations and identify which combination logically supports the need for tissue-level organization, body coordination, and reproductive diversity across phyla:
1. Earthworm exhibits metameric segmentation and a closed circulatory system, but its neural system is represented by a nerve ring and paired ganglia, unlike the tripartite brain of frog protected in a cranium.
2 Frog's three-chambered heart, double circulation, and presence of hepatic and renal portal systems reflect a significant evolutionary advancement over the open circulatory system of cockroach and the dorsal vessel of earthworm.
3 In humans, areolar connective tissue supports internal organs and forms a framework, functionally analogous to fat bodies in frogs and spongy hemocoel in cockroaches.
4. Both cockroach and frog are ureotelic, but only frogs possess nephrons in kidneys, cloacal excretion, and bidirectional air exchange via lungs and skin, unlike tracheal respiration in cockroach.
5. Epithelial tissues form linings in all animals, but compound epithelium is specific to human skin, whereas simple columnar epithelium in frog’s intestine supports absorption aided by villi and microvilli.
6. Sexual dimorphism in frogs is seen in vocal sacs and copulatory pads, while in cockroach, it’s identified via anal styles and caudal appendages; however, both follow external fertilization unlike earthworm’s hermaphroditic copulation.
Which of the following options is most appropriate?
(a) Only 1, 2, 4, and 5 are correct
(b) Only 1, 2, 3, 4, and 6 are correct
(c) All statements (1 to 6) are correct
(d) Only 1, 2, 3, and 5 are correct
NCERT EXEMPLAR
1. Which one of the following types of cell is involved in making of the inner walls of large blood vessels?
(a)Cuboidal epithelium
(b) Columnar epithelium
(c) Squamous epithelium
(d) Stratified epithelium
2. Which one of the following categories does adipose tissue belong?
(a) Epithelial (b) Connective
(c) Muscular (d) Neural
3. Which one of the following is not a connective tissue?
(a) Bone (b) Cartilage
(c) Blood (d) Muscles
4. The clitellum is a distinct part in the body of earthworm, it is found in
(a) segment 13 - 14 - 15 (b) segment 14 - 15 - 16
(c) segment 12 - 13 - 14 (d) segment 15 - 16 - 17
5. Setae help in locomotion in earthworm but are not uniformly, present in all the segments. They are present in
(a) 1st segment (b) last segment
(c) clitellar segment (d) 20th - 22nd segment
6. Which one of the following statements is true for cockroach?
(a) The number of ovarioles in each ovary are ten (b) The larval stage is called caterpillar
(c) Anal styles are absent in females
(d) They are ureotelic
7. Match the following.
Column I
Column II
A. Adipose tissue 1. Nose
B. Stratified epithelium 2. Blood
C Hyaline cartilage 3 Skin
D. Fluid connective tissue 4. Fat storage A B C D A B C D
8. Match the following. Column I Column II
A. Hermaphrodite 1. Produces blood cells
and haemoglobin
B. Direct 2. Testis and ovary in the development
C. Chemoreceptor 3. Larval form absent
D Blood gland in 4 Sense of
same animal chemical substances
A B C D A B C D
(a) 2 3 4 1 (b) 3 2 4 1
(c) 1 3 2 4 (d) 2 4 3 1
9. Match the following with reference to cockroach and choose the correct option.
Column I
Column II
A Phallomere 1 Chain of developing ova
B. Gonopore 2. Bundles of sperm
C. Spermatophore 3. Opening of the ejaculatory duct
ejaculator y duct
D Ovarioles 4 The external genitalia
A B C D A B C D
(a) 3 4 2 1 (b) 4 3 2 1 (c) 4 2 3 1 (d) 2 4 3 1
10. Match the following.
Column I
Column II
A. Touch 1. Nasal epithelium
B. Smell 2. Foramen magnum
C. Cranial nerves 3. Sensory papillae
D Medulla oblongata 4 Peripheral nervous
earthworm system
A B C D A B C D
(a) 3 1 2 4 (b) 2 1 4 3
(c) 3 4 2 1 (d) 3 1 4 2
NCERT EXEMPLAR
1. a 2 c 3. d
4. a 5 b
6. False 7. c 8 a 9. b 10. d 11 b 12. c 13. d 14 d
