Topic 6: Human Physiology

Digestion

breakdown large molecules of nutrients by small building blocks that the body can absorb

mouth

mechanical breakdown of food by chewing with saliva which contains lubricants.
- Enzymatical breakdown: salivary amylase.
- pH is 7

Esophagus

Peristaltic movements pushing food towards the stomach

stomach

- Enzymatical breakdown - enzyme pepsin.
- Mechanical breakdown - churning and mixing with secreted water and acid
- acid kills foreign bacteria and other pathogens in food.
- Acid gives optimum pH for pepsin so the initial stages of protein chemical digestion happen here
- protein ----- pepsin----- dipeptides

liver

- stores glcyogen
- breakdown of toxic prducts
- production of bile, emulsifier
- secretion of surfactants (emulsifiers) in bile to break up lipid droplets

gall bladder

storage and regulated release of bile

pancreas

- production of bicarbonate, trypsin, pancreatic amylase, lipase
- insulin production: beta cells of the islets of langertrons
-- glucogen production: production of alpha cells of the islets of langetrons
- secretion of lipase, amylase and protese, transported by ducts to small intestine, therefore exocrine gland

large intestine

- absorption of water
- many bacterias found in the large intestine, very important for our immune system
- formation and storage of feces

small intestine

- lipids ---- glycerol
- disaccharides---- pancreatic amylase--- monosaccharides
- dipeptides -- trypsin --- amino acids
- pH 7
- ileum: absorption of nutrients
- neutralising stomach acid
- final stages of chemical digestion of lipids, carbohydrates, proteins, nucleic acids

rectum

undigested food will come out