HUN1201

digestion

breaks downs foods into nutrients in preparation for absorption

absorption

the uptake of nutrient by cells of the small intestine for transport into either the blood or lymph

challenges of digestion

multiple tasks of the mouth, passage through diaphragm, steady movement, lubrication of food, digestive enzyme functions, excretion of wastes

gi tract

flexible muscular tube that extends from the mouth, through the esophagus, stomach, small intestine, large intestine, and rectum to the anus

lumen

inner space within the gi tract that is continuous form one end to the other

mouth

chews and mixes food with saliva

process of digestion begins in

the mouth

pharynx

directs food from mouth to esophagus

salivary glands

secrete saliva

epiglottis

protects airways during swallowing

trachea

allows air to pass and from lungs

esophagus

passes food from mouth to stomach

esophageal spincters

allows passage from mouth to esophagus and from esophagus to stomach; prevent backflow from stomach to esophagus and from esophagus to mouth

diaphragm

seperates the abdomen from the thoracic cavity

stomach

churns, mixes, and grinds food to a liquid mass; adds acid, enzymes, and fluid

bolus moves into

the stomach

pyloric sphincter

allows passage from stomach to small intestine; prevents backflow from small intestine

liver

manufactures bile salts, detergent-like substances, to help digest fats

gallbladdder

stores bile until needed

bile ducts

conduct bile from the liver to the gallbladder and form the gallbladder to the small intestine

appendix

houses bacteria and lymph cells

small intetsine

secretes enzymes that digest all energy-yielding nutrients to smaller nutrient particles; cells of wall absorb nutrients into blood and lymph

ileocecal valve (sphincter)

allows passage from small to large intestine; prevents backflow from large intestine

pancreas

manufactures enzymes to digest all energy-yielding nutrients and releases biocarbonate to neutralize acid chyme that enters the small intestine

pancreatic duc

conducts pancreatic juice to the small intestine

large intestine (colon)

absorbs water and minerals; passes waste along with water to rectum

rectum

stores waste prior to elimination

anus

holds rectum closed; opens to allow elimination

taste buds detect one, or a combination, of the five basic taste sensations:

sweet, sour, bitter, salty, and umami

peristalsis

circular and longitudinal muscles working together push intestinal contents along, rate and intensity of contractions vary

segmentation

contraction of circular muscles in small intestine: mixes chyme, promotes contact with digestive juices and absorption; sphincter contraction: periodically open and close, close pace of movement of GI tract contents

the secretions of digestion

Five organs: Salivary glands, stomach, pancreas, liver, and small intestine ; Secretions; Water; Enzymes; Protein facilitator of chemical reactions; Hydrolysis