Digestive system • ?. mouth • A. oesophagus • B. stomach • G. small intestine • ?. Duodenum • ?. digestion – bile • - enzymes • D. large intestine • ?. the anus • E. Liver • F. Gall Bladder • C. Pancreas
What do these words mean? • Ingestion • Digestion • Absorption • Assimilation • Egestion
Digestion • 2 types – mechanical and chemical digestion. • Digestion is speeded up by enzymes (biological catalysts). • Muscles are also responsible for moving food along the gut (circular and longitudinal muscle layers). • Waves of muscle contraction help push the food along the gut – peristalsis.
Digestion Duodenum • The mouth, stomach and first part of the small intestine make up the duodenum. • They all break down the food using enzymes. Ileum • Digestion continues in the last part of the small intestine (ileum). • This is where the digested food is absorbed.
Digestion • The last part of the gut, the large intestine is mainly concerned with absorbing water out of the remains and storing waste products (faeces) before they leave the body.
Ingestion • Taking food into the body (very start of the digestive system).
Digestion • Large insoluble molecules are broken down into small soluble molecules. • Starch digestion begins. • Protein digestion begins. • All types of digestion occur.
Absorption • The transfer of digested substances from the intestine into the blood. • Majority of absorption. • Water absorption
Assimilation • The soluble products of digestion are taken to cells and used to make structures in the cells. • E.g. glucose converted to glycogen • Amino acids built up into proteins • Fatty acids and glycerol turned into lipid for storage.
Egestion • Removable of waste material that could not be digested.