Digestive System ORGANISATION AND THE DIGESTIVE SYSTEM Flashcards
What is digestion?
The food you take in is made up of large insoluble molecules. Your body cannot absorb and use these molecules. They need to be broken down or digested to form smaller, soluble molecules that can be absorbed and used by your cells.
What happens in the small intestine?
Where soluble molecules are absorbed into your body. It is adapted to have a large surface area with Villi. It’s muscular walls squeeze undigested food onwards into your large intestine.
What happens in the large intestine?
Water is absorbed from the undigested food into your blood.
What happens in the liver?
Production of bile which helps digest lipids.
What PH is in the stomach?
The stomach is acidic. (Hydrochloride acid). This is good for the protease enzymes and it kills bacteria.
How is the stomach adapted?
Thick layer of mucus. This protects the layer of your stomach from being digested by the acid and the enzymes.
What conditions are in the small intestine?
The enzymes in your small intestine all work best in alkaline environments. This means that the PH needs to change from acidic to alkaline. So this can happen, your liver makes bile. Bile is stored in the gall bladder until it is needed. As food enters the small intestine, bile is squirted on it through the bile duct. This neutralises the acid and provides the alkaline conditions needed.
What does bile do?
Creates alkaline conditions.
Emulsifies the fats. It physically breaks up large droplets of fat into smaller droplets. This provides a bigger surface area for data for the lipase enzymes to act upon. The larger surface area helps the lipase chemically break down the fats more quickly into fatty acids and glycerol.
