Adapted from "Nelson 11" Text, pg. 229.

Table 1: Physical and Chemical Digestion
mouthchewing of food and digestion of starch by salivary amylase
esophagustransport of food from mouth to stomach; lubricated by mucus
stomachstorage of food and initial digestion of proteins + fats; production of the hormone gastrin (response to protein) that stimulates stomach's gastric glands to release gastric juice (including pepsin and HCl)
small intestinecontinued digestion of carbohydrates, proteins, lipids; most absorption of nutrients; production of the hormone secretin (response to HCl) that stimulates pancrease to release bicarbonate; production of the hormone CCK (response to fat) that stimulates gall bladder to release bile
pancreasproduction of digestive enzymes that act in small intestine; production of the hormones insulin and glucagon which regulate blood sugar; production of bicarbonate that neutralizes stomach acid in small intestine
large intestineabsorption of water; production of some vitamins; storage of undigested food

Table 2: Substances Involved in Digestion
OrganSecretion and Function
salivary glandssalivary amylase - converts starch (a polysaccharide) to maltose (a disaccharide)
esophagusmucus - helps movement of food
stomach hydrochloric acid - converts pepsinogen to pepsin and kills microbes

pepsinogen - when converted to pepsin, initiates digestion of proteins (long chains of amino acids) to polypeptides and peptides (shorter chains of amino acids)

lipase - converts lipids (eg. triglycerides) into glycerol and fatty acids

mucus - protects stomach from pepsin and HCl

renin - coagulates proteins in milk to slow movement

pancreas; small intestine pancreatic amylase - converts starch (a polysaccharide) to maltose (a disaccharide)

bicarbonate - neutralizes HCl from stomach

enterokinase - converts trypsinogen to trypsin

trypsinogen - when converted to trypsin, converts proteins into peptides

erepsin - converts peptides into amino acids

lipase - converts lipids (eg. triglycerides) into glycerol and fatty acids

maltase - convets maltose (a disaccharide) into two glucose (a monosaccharide)

sucrase - convets sucrose (a disaccharide) into glucose and fructose (monosaccharides)

lactase - convets lactose (a disaccharide) into glucose and galactose(monosaccharides)

liverbile - emulsifies fat (large globules into smaller ones for lipase to work)
gall bladderbile - stores concentrated bile from liver
large intestinemucus - helps movement of food