Download Salivary Amylase

DIGESTION SUMMARY
MOUTH
 Salivary gland
 Starch –Amylase maltose
STOMACH
 Hydrochloric acid
 Gastric juices – controlled by hormone called Gastrin – food in mouth
 Pepsinogen –contact with acid Pepsin
 Proteins –pepsin polypeptides
 Mucin – forms a layer of mucus
 After 3-4 hours - chyme
DUODENUM
 Pancreas
o Starch –amylase Maltose
o Lipids –Lipase Fatty acids and glycerol
o Trypsinogen –activated by enterkinase made in intestinal glands Trypsin (endopeptidase)
o Chymotrypsinogen – trypsin activates  Chymotrypsin (exopeptidase)
o Proteins –(Trypsin + Chymotrypsin) polypeptides + amino acids
 Liver
o Bile Emulsify fats  micelles
o Sodium hydrogen carbonate - Neutralises acidic chime
SMALL INTESTINE
 Wall of Small Intestine
o Pancreozymin (CCK) – is produced when fat-rich chime enters the duodenum. Triggers
release of pancreatic enzyme and release of Bile.
o Secretin – triggered from acidic chime - stimulates flow of hydrogen carbonate ions from
pancreas
o Enterkinase – activates trypsinogen  trypsin
o Starch –amylase maltase
o Maltase –maltose glucose
o Sucrose –sucrase  glucose and fructose
o Lactose –lactase glucose and glactose
o Dpeptides –peptidase amino acids
o Peptides –aminopeptidase amino acids
o Nucleotides—neucleotidase organic base + pentose sugar + phosphate

Absorption
o Epithelium secretes sodium and chloride ions into the lumen  water potential gradient 
water moves into lumen by osmosis
o Absorption of glucose
 Sodium is responsible for the absorption of water, amino acids and glucose
 Glucose is absorbed by active transport – requires sodium dependent glucose
transporters – proteins transport both sodium and glucose into the cell
 Once inside the epithelium, glucose and sodium must be exported from the cell into
the blood – diffusion
 Other monosaccharides such as fructose are not absorbed by active transport
o Absorption of amino acids
 Sodium-dependent amino acid transporters
 Active transport of sodium and amino acids
o Absorption of Lipids
o Emulsification  bile salts and lipids  micelles
o Fatty acids and monoglycerides are absorbed by simple diffusion across plasma membrane
LARGE INTESTINE
 Water and electrolytes (i.e. sodium and chloride) are absorbed
 Na+ transported from lumen by sodium pumps, water follows by osmosis
 Bicarbonate is secreted to neutralise acids generated from microbes