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Digestion has
7 stages, the mouth, oesophagus, liver, stomach, pancreas, small intestine, and the large intestine.
The process of digestion is really to turn large food molecules into smaller ones, that we can digest. We do this in two ways:- breaking it down physically by chewing or chemically by enzymes.
Our digestive system starts with eating food. Different foods have different properties which our body exploits in multiple ways.
The chewing motion signals the stomach that the body is about to receive food. This is why saliva is produced.
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1.The Mouth/Buccal cavity is where food is masticated (chewed). The buccal and naval cavity also warm up the air so that it does not interfere with enzyme production. The saliva, which contains Carbohydrase enzymes, changes starch into maltose.
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2.Oesophagus/Gullet is where food is transported from the both to the stomach. These contract and push food along the gut, this is called peristalsis.
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3.The Liver breaks up (emulsifies) fats by storing bile (the bile actually comes from the gall bladder). It is also alkaline which is good for the enzymes by giving them a good pH for them in the small intestine.
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4.Stomach is where
enzymes break down your food.
In your stomach starch, fat and protein are digested by enzymes.
Hydrochloric acid is present to kill and neutralise bacteria which gives a low pH for the enzymes to work.
Enzymes work perfectly at human body temperature at ice temperature, enzymes become deactivated but above body temperature they become denatured.
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5.Pancreas is where
three types of enzymes are produced:
Protease enzymes to digest proteins.
Lipase enzymes to digest lipids e.g.. Fats.
Carbohydrase enzymes to digest carbohydrates
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6.Small Intestine produces more enzymes to break up more proteins, fats and carbohydrates. It also absorbs the nutrients through the gut wall and into the blood stream through these ingenious cells, the villi which line the small intestine which are specially designed to absorb food efficiently. This process is a form of diffusion. Diffusion is the process of which a substance, commonly gas, transfers from a state of high concentration to low concentration to create balance
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7.Large Intestine absorbs water and indigestible foods are stored here. The leftover material is depostied throught the rectum.
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