HUMAN PHYSIOLOGY NUTRITION Heterotrophic- organic molecules needed Carbohydrates- hydrolysis to simple sugars, excess sugar is stored as glycogen or fat (energy reserve), cellulose provides roughage (helps food move in through intestine) Proteins- hydrolysis to amino acids (build and repair tissue), amino acids are broken down by deamination and stored as fat, humans require 8 essential amino acids for protein synthesis

Lipids- hydrolysis to 3 fatty acids and glycerol, saturated fat (solid, heart disease), unsaturated fat (liquid, better) Inorganic nutrients- water, vitamins, minerals

Human digestive system Mouth- mechanical digestion (surface area), chemical digestion (hydrolysis of starch to sugar with the secretion of amylase by salivary glands Esophagus-peristalsis (muscular movements of food through tract) Stomach- mechanical digestion, chemical digestion of proteins to amino acids which are broken down by deamination

Small intestine- most chemical digestion (all end products- amino acids, simple sugars, fatty acids, glycerol are absorbed by villa which provide excess surface area, then diffuse into blood where they are transported to cells) Liver- secretes bile which is stored in gall bladder and passed to small intestine where fats are emulsified (broken down)

Pancreas- secretes pancreatic juice which passes to small intestine (includes lipase, protease, amylase) Large Intestine- reabsorbs excess water, forms feces (indigestible material), re-absorbs vitamins Constipation- too much water is absorbed, feces are hard Diarrhea- not enough water is absorbed, watery feces

Rectum- stores feces Anus- removes feces