Digestive System

Gastrointestinal

Muscular tube from mouth to anus

Ingestion

Taking in of food

Defecation

Elimination of waste

Digestion

Chemical breakdown of food

Absorption

Movement of nutrients into blood

Secretion

Release of digestive fluids

Parietal

Membrane lining abdominal cavity

Visceral

Peritoneum covering organs

Parietal (body wall)

Peritoneum lining body wall

Fluid

Reduces friction in abdomen

Mesentery

Suspends digestive organs

Mucosa

Innermost layer of GI tract

Submucosa

Contains blood vessels and nerves

Muscularis

Responsible for movement

Serosa

Outermost layer

Peristalsis

Propels food forward

Segmentation

Mixes food without moving it forward

Tongue

Forms a bolus

Lipase

Begins lipid digestion

Mastication

Chewing

Enamel

Hardest substance in the body

Incisors

Cutting teeth

Canines

Tearing teeth

Molars

Grinding teeth

Parotid

Produces most saliva

Submandibular

Produces watery secretion

Amylase

Digests carbohydrates in mouth

Deglutition

Swallowing

Esophagus

Carries food to stomach

Chyme

Semi-liquid stomach content

Pepsin

Digests proteins in stomach

Parietal cells

Secrete HCl

Gastrin

Stimulates gastric secretion

Acinar cells

Secrete digestive enzymes

Insulin

Lowers blood sugar

Lobule

Functional unit of liver

Bile

Helps digest fats

Gallbladder

Stores bile

Duodenum

First part of small intestine

Villi

Increase absorption surface area

Lacteals

Absorb fats

Colon

Absorbs water and forms feces

Cecum

Begins compaction

Haustra

Pouches in colon wall

Rectum

Stores feces

Anus

Exit of digestive tract

External sphincter

Voluntary sphincter

Vitamin K

Produced by gut bacteria

Stercobilin

Gives feces brown color

Hydrogen sulfide

Causes foul odor