T HE I NTESTINES The Digestive System

S MALL INTESTINE about 20 feet long and about 1”in diameter Food, still mixed with gastric juice enters duodenum from the stomach The semi liquid, highly acidic food needs to be neutralized and digested further Three parts: duodenum, jejunum (middle), and ileum (meets with large intestine)

A BSORPTION digested food is ABSORBED through the wall of the small intestine into the blood stream To do this effectively, needs to have a large surface area wall is covered in villi (small finger like structures)

LIVER Large organ- upper right abdominal cavity, below diaphragm Left and right lobes filters (removes toxins) blood from the digestive tract before passing it to the rest of the body secretes bile  to small intestines  break down fats Gallbladder- under liver, stores excess bile

PANCREAS 6 inches long  behind the stomach connected to the duodenum Gland  release hormones  insulin and glucagon  regulate blood sugar levels

P ANCREATIC ENZYMES Pancreatic juice = water, salts, bicarbonate, many enzymes neutralize the acid in chyme Pancreatic amylase  breaks down large polysaccharides like starches and glycogen into smaller sugars Trypsin  break down proteins into their amino acids Pancreatic lipase  breaks down fats

APPENDIX Where small and large intestine meet thin tube- 4” long function unknown acts as a storehouse for good bacteria, “rebooting” the digestive system after diarrheal illnesses a useless remnant from our evolutionary past- break down cellulose in plant matter

L ARGE I NTESTINES About 5 feet long and about 3 inches in diameter Undigestible food (e.g. fiber) passes into the large intestine (colon) Water absorbed back into the body Creates solid waste= feces. Feces stored in the rectum and removed through the anus (defecation)

Digestive Organs Review