NOTES DIGESTIVE SYSTEM ANATOMY Interesting Digestive System Facts

NOTES – DIGESTIVE SYSTEM ANATOMY

Interesting Digestive System Facts After you eat how long does it take for the stomach to empty? Within 2 -6 hours, all food is emptied into the small intestine.

How many pounds of food does the average person eat in a year? 1, 100

How many feet long are your intestines? about 20 -30 ft long.

NOTES – DIGESTIVE SYSTEM ANATOMY • Oral Cavity • mouth, pharynx, esophagus

• MOUTH • SALIVARY GLANDS – produce saliva

• Saliva Components • Mostly water – about 99. 5% • SALIVARY AMYLASE – digests starch • LYSOZYME – antibacterial action • MUCIN – lubricant • chewing and saliva with food form a BOLUS

• PHARYNX • common area for food and air • Epiglottis • prevents food from entering the trachea (wind pipe)

• ESOPHAGUS • transports bolus from pharynx to stomach • involuntary muscular movement of food - PERISTALSIS

• STOMACH • a storage & mixing chamber • secretions • mucus • hydrochloric acid (HCl) • HCl activates pepsinogen to pepsin which is main enzyme that digests protein

• movement • mixing waves - peristalsis • bolus becomes chyme

• SMALL INTESTINE • parts: duodenum, jejunum, ileum • Function: • digestion and absorption • intestinal juice – water & mucus • epithelial cells have digestive enzymes to digest ALL classes of food

• LIVER • performs many functions – main blood filter in digestive system • in digestion it secretes BILE into the gall bladder • the gall bladder then dumps bile into small intestine

• bile EMULSIFIES fats – breaks fat into smaller pieces – easier for fat digesting enzymes to do their work Normal liver fatty liver Cirrhosis of the liver

• PANCREAS • pancreatic enzymes are important for the digestion of all major classes of food • four enzymes and bicarbonate • all are dumped into small intestine

• LARGE INTESTINE • Parts: ascending colon, transverse colon, descending colon, sigmoid colon • chyme is converted to feces • absorption of water & salts • E. coli bacteria synthesizes vitamin K