Digestion Flashcards
What is digestion?
The food we eat has to be broken down into other substances that our bodies can use like nutrients.
Parts of the digestive system
Mouth, oesophagus, stomach, small intestine, large intestine, salivary glands, liver, pancreas, rectum and anus.
4 Stages of digestion
ingestion (eating) → digestion (breaking down) → absorption → egestion (removal from the body)
Which organ produces bile, which helps the digestion of lipids (fats and oil).
Liver
What does the pancreas do?
Produces digestive enzymes which speed up the digestive reactions.
What are enzymes?
Proteins that break larger molecules of food into smaller ones. Different enzymes break down different nutrients.
What are the three different enzymes?
Carbohydrase enzymes
Protease enzymes
Lipase enzymes
Carbohydrase enzymes
Carbohydrase enzymes break down starch into sugar in the mouth, stomach and small intestine.
Protease enzymes
Protease enzymes break down proteins into amino acids in the stomach and small intestine.
Lipase enzymes
lipase enzymes break down lipids (fats and oils) into fatty acids and glycerol in the small intestine.
What substances are not digested?
Minerals, vitamins and water are already small enough to be absorbed by the body without being broken down, so they are not digested.
Ingestion
Food is taken into the mouth where it is physically broken down by the teeth into smaller pieces. The presence of food in the mouth triggers a nervous reflex that causes the salivary glands to deliver a watery fluid called saliva to the mouth.
Absorption
Digested food molecules are absorbed in the small intestine. This means that they pass through the wall of the small intestine and into our bloodstream. Once there, the digested food molecules are carried around the body to where they are needed.
Egestion
Excess water is absorbed back into the body in the large intestine. Any undigested food passes out of the anus as faeces when we go to the toilet
