Another substance is added from the gall bladder; bile, made in the liver and stored in the gall bladder, contains no digestive enzymes. It contains bile salts (breakdown products of dead red blood cells), which play a vital role in the digestion of fat. Bile salts hydrolyses large fat drops into tiny droplets, which can mix better with water to create an emulsion. This makes it easier for lipase to digest the chemicals as it increases the surface area of the fat. The pancreatic secretions contain hydrogen carbonate ions to neutralise the stomach acid. The enzymes of the small intestine work best in a slightly alkaline environment. An alkali has a pH above 7. pH is the measurement of how acidic or alkaline the water is. It ranges from 0 - 14, whereby an acid is from 1- 6, 7 is neutral and an alkali is from 8 - 14. The diet has an impact on the pH of the blood, whereby some food contains high acidic levels, whereas others contain more alkaline. Consuming food that has a high alkaline content such as fruits, vegetables and whole grains as well as eating less acidic food improves health.
Ileum As the food is digested, the products are absorbed into the blood. This takes place in the ileum before moving into the large intestine. This is a long and narrow tube and is the last part of the small intestine. Absorption is the ability to travel through the walls of the small intestines and into the blood stream, to go where they are needed. For instance, glucose is needed to provide cells energy. Substances that are able to pass through are termed ‘soluble’, whereas those that cannot are termed ‘insoluble’. Only small, soluble substances can pass through. However, large, insoluble substances are unable to pass through the wall. The ileum is adapted for absorption as it is folded, which increases the surface area. The surface is covered with tiny (about 1mm long) finger-like projections called villi. The cells on the surface of the villi have tiny finger-like projections on their cell membrane called micro-villi. Villi has a blood capillary network and its function is to remove absorbed food molecules. The intestinal wall is also thin. Without these adaptations; digested food may not be absorbed before it is egested through the anus.
Ilma Magazine / Issue 19
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