Digestive System A&P

alimentary canal

digestive tract consisting of a tube running between the mouth and the anus

salivary glands

three pairs of exocrine glands in the mouth that secrete saliva; the parotid, submandibular (submaxillary), and sublingual glands

gallbladder

stores and concentrates the bile produced in the liver

liver

produces bile and stores glycogen

pancreas

produces insulin and glucagon, enzymes, and sodium bicarbonate

mouth

oral cavity; mechanical digestion (chewing) and chemical digestion of carbs start

pharynx

the throat; last place food and air mix

esophagus

muscular tube that connects the mouth to the stomach

stomach

large muscular sac that continues mechanical digestion and starts chemical digestion of proteins

small intestine

organ in which most chemical digestion takes place

large intestine

organ that absorbs water from undigested material

rectum

lower part of the large intestine where feces are stored

ingestion

process of taking in food

mechanical processing

physical breakdown of foods

chemical digestion

process in which enzymes and other chemicals are used to break foods into their smaller chemical building blocks

secretion

process of producing a substance within an organ and discharging it

absorption

process by which nutrient molecules pass through the wall of the digestive system into the blood

elimination

process of passing undigested material out of the anus

defecation

elimination of fecal waste through the anus

duodenum

first portion of the small intestine which receives secretions from the gallbladder and pancreas

ileum

last and longest portion of the small intestine where most absorption takes place

jejunum

second portion of the small intestine where most chemical digestion is completed

Peyer's patches

collections of lymphatic tissue found along the length of the small intestine

propulsion

movement of food from one organ to the next

peristalsis

involuntary waves of muscle contraction that keep food moving along in one direction through the digestive system

segmentation

rhythmic mixing of chyme with digestive enzymes in the small intestine

mucosa

innermost layer of digestive tract

submucosa

layer superficial to the mucosa which contains blood vessels, lymph vessels, and nerves

muscularis externa

bilayer of smooth muscle which consists of a layer running circularly and another running longitudinally

serosa

outer layer the alimentary canal; secretes a watery fluid to reduce friction

visceral peritoneum

serous membrane that covers abdominal organs

parietal peritoneum

serous membrane that lines the abdominal cavity

mesenteries

connective tissues that anchor organs to the body wall and provide a pathway for nerves and blood vessels

tongue

muscular organ which assists with chewing, swallowing, and taste

tonsils

clusters of lymphatic tissue found in the pharynx

mastication

chewing

haustra

pouches of the large intestine that allow expansion and elongation

anus

muscular opening at the end of the rectum

cecum

first part of the large intestine where appendix is attached

glucagon

pancreatic hormone that raises blood sugar

insulin

pancreatic hormone that lowers blood sugar

microvilli

extensions of the plasma membrane that increase its surface area

villi

projections inside the small intestine that increase the surface area for absorption of nutrients

bile

a substance produced by the liver that breaks up fat particles

ileocecal valve

sphincter separating the small and large intestine

rennin

a milk protein-digesting enzyme found in babies but not adults

gastrin

hormone secreted by stomach cells that signal glands in stomach to release gastric juice

chyme

acidic, semiliquid mass of partially digested food and gastric juice

pepsin

enzyme hat begins the breakdown of proteins in the stomach

mucus neck cells

produce an acidic mucus in the stomach

parietal cells

produce hydrochloric acid which kills bacteria and activates pepsinogen

chief cells

secrete pepsinogen, the inactive form of pepsin, in the stomach

goblet cells

secrete an alkaline mucus to protect the lining of the small intestine from stomach acid

salivary amylase

enzyme in saliva that begins the breakdown of carbs

saliva

contains mucus, enzymes, and water; moistens food

deglutition

swallowing

soft palate

soft part of the back of the roof of the mouth, closes off nasal cavities when swallowing

epiglottis

flap of cartilage that covers the trachea while swallowing

cardioesophageal sphincter

muscular opening between the esophagus and stomach

pyloric sphincter

circular muscle that controls the movement of chyme from the stomach to the small intestine

bolus

chewed up clump of food

rugae

numerous folds of the stomach which allow the stomach to be able to expand