Digestive System

small intestines are

22 feet long

mechanical digestion

physical breakdown, stomach churning, chewing

chemical digestion

chemical breakdown by enzymes and acids

mouth

where you eat, mostly mechanical digestion

saliva

mostly water and salt, has enzyme amylase for starch

salivary gland

digests starch

esophagus

tube/pathway to the stomach (gullet)

alimentary canal

gastrointestinal tract (GI)

GI tract

mouth—> pharynx—>esophagus—>stomach—>small intestine—>large intestine

sphincter

between esophagus and stomach (lower esophageal)

pharnyx

back of throat

epiglottis

flap of cartilage, covers trachea when swallowing

peristalsis

involuntary waves of muscle contraction

stomach

stores and breaks down food

gastric juice

converts meal to acidic chyme

parietal cells HCI

pH 2, kills bacteria, denatures protein

pepsin

enzyme breaks down proteins

rugae

large folds

mucus

protects lining of the stomach

chief cells

secrete pesinogen

pyloric valve

sphincter located at the base of the stomach where it connects to stomach intestines

three regions of the stomach

cardiac, fundus, and body

fundus

holds air, why you burp

gastrin

hormone that stimulates secretion of gastric juice and is secreted into the bloodstream by the stomach wall in response to the presence of food

small instestine

moves faster than the large, digestion and absorption

duodenum

(first section), digestive juices, major chemical digestion

jejunem

(second section), absorb nutrients

illeum

(third section), absorb vitamin B12, bilesalts, remaining nutrients

amylase lactase and maltase

help digest carbohydrates

folds, villi and microvilli

(absorptive effectiveness), increase surface are for absorption

digestive glands

secrete enzymes into duodenum

pancreas

neutralize acidic chyme (bicarbonate), enzymes (carbs, proteins, fats) produce insulin

bile salts

made in liver, stored in gallbladder, digestion and absorption of fats (make smaller droplets)

large instestine (cecum, colon, rectum)

absorb water, eliminate food residue

cecum

pouch where SI and LI meet, ferment plant material

appendix

extension of cecum, role in immunity

bacteria

make vitamin K, produce gases

rectum

feces stored until elimination

colon

ascending, transverse, descending

liver

composed of four lobes, right, left, caudate, and quadrate

liver function

filter poisons, store nutrients, destory damaged RBC, produce bile

common pancreatic duct

joins of hepatic duct with cystic duct