DIGESTIVE SYSTEM CH 14 Alimentary canal or GI

DIGESTIVE SYSTEM CH 14 Alimentary canal or GI tract_____________________ Organs include: mouth, pharynx, esophagus , stom , small intestine and large intestine Mouth or oral cavity is a mucous lined membrane Composed of uvula, hard&soft palate and tongue (lingual frenulum). Tonsils Purpose = mastication

PHARYNX- (nasopharynx, oropharynx, and laryngoph. . ) ESOPHAGUS-10 inches long passageway for food occurs through peristalsis-__________ Walls of GI tract contain 4 types of tissue: 1. Mucosa-lining 2. Submucosa – blood vessels, lymph nodes, nerve ending 3. Muscularis externa – has smooth musc cells 4. serosa-has visceral peritoneum

STOMACH-10 inches and includes (cardioesophageal sphincter, fundus, body, pyloris and pyloric sphincter) Holds 1 gallon of food and composed of rugae-______ Stomach lined w/ musles (muscularis externa) to help churn and mix. Chemical process-stom. lined w/ ______ pits, which secrete gastric juice. (HCL “parietal cells” and pepsinogen “chief cells”and mucous) ____-heavy cream like now ready for S. Intestine

SMALL INTESTINE-(6 -13 feet) suspended by fan shaped mesentery. 3 subdivisions (duodenum, jejunum, ileum). Finishes at ileocecal valve. Chemical digestion occurs here w/ help of pancreas (pancreatic duct attaches at duodenum) and bile released in bile duct produced from liver) see p 439! Food absorption occurs here Microvilli______ Villi_________ composed Of lacteal w/ capillaries

Helps surface area LARGE INTESTINE-(5 feet) purpose ______ 3 divisions (ascending, transverse, descending) also cecum, sigmoid colon, rectum. No villi but goblet cells which secrete _____. Purpose: ________ READ p 442 -448 & 450 -451

Stomach: Gastric juice released by ____. Also hormone _____ by food and lower p. H in stomachhelps release Pepsinogen for _____ and HCL. 2 -3 L of gastric juice produced a day. Problems: heartburn…leads to ESOPHAGITIS and Ulcers! Rennin another milk digesting protein Alcohol and Asprin only thing absorbed in stomach Eventually muscles mix for chyme!

Food enters S. I thru ____ sphincter and allows 3 ml of chyme to enter. Then a enterosgastric reflex occurs to slow emptying. Takes 4 hrs to process. 6 hrs if high fat! Vomit Commit from _______ or food poisoning. Causes signal emetic center (brain) to induce. Also inner ear imbalance. ACTIVITIES OF S. I No fats digested yet. Takes 3 -6 hrs. Villi have brush boarder enzymes that break down sugars. But lots of pancreatic juice (p. H of 8) found here ducted from _____.

Problems: Pancreatitis Pancreatic juice stimulated by nerves and hormones ____ and ___ (secretin-liver to increase bile production and CCK-release of bile from GB) Bile not an enzyme but an emulsifier (breaks fat into smaller particles) also helps absorb vit K, Dand A! If no bile (fatty bulky stools) and poor clotting from vit K All that’s left _____, ______, and lots’o bacteria!

L. I Activities: 12 -24 hrs, bacteria metabolize remnantsproduce some gas. Function: reabsorption of vitamins K and B and ______! Movement by Peristalsis and mass movements Problems: Constipation, Diarrhea Diverticulitis