Chapter 23 - The Digestive System Flashcards
Major divisions of the digestive system
alimentary canal (GI tract) accessory digestive organs
alimentary canal (GI tract)
extends from mouth to anus
is a continuous tube about 30 feet long
includes oral cavity, pharynx, esophagus, stomach, small investing, and large intestine
It usually takes about 24-48 hours for food to travel the entire length of the GI tract
accessory digestive organs
connected by ducts
teeth, tongue, salivary glands, liver, gallbladder, pancreas
Ingestion
taking food into the mouth
mastication
chewing
grinds up food and mixes it with saliva
occurs in mouth
deglutition
swallowing food
moves it from mouth to pharynx to esophagus
voluntary
peristalsis
rhythmic, wave-like intestinal contractions that move food through the GI tract
involuntary
digestion
mechanical and chemical breakdown of food material to prepare it for absorption
segmentation
local, rhythmic contraction of small intestine
absorption
passage of molecules of food through mucous membranes of small intestine and into blood or lymph for distribution to cells
defecation
discharge of indigestible wastes from GI tract
mechanical digestion organs
mouth
stomach
sm. intestine
chemical digestion organs
stomach
small intestine
absorption organs
small intestine
large intestine
peristalsis organs
esophagus
stomach
small intestine
large intestine
peritoneum
serous membrane of abdominopelvic cavity
2 types = visceral and parietal
visceral peritoneum
covers external organ surfaces, is continuous with parietal peritoneum
parietal peritoneum
lines the body wall
peritoneal cavity
space in between visceral and parietal peritoneum
contains serous fluid
mesentery
double layer of peritoneum that holds organs in place, stores fat, allows blood vessels and nerves to get to organs in peritoneal cavity
mucosa
mucous membrane with 3 sub-layers: epithelial linging, lamina propria, muscularis mucosae
submucosa
CT layer with lots of blood and lymphatic vessels, nerve fibers
muscularis externa 2 layers
inner circular, outer longitudinal
Serosa
is the visceral peritoneum
nerve plexuses
receive signals from SNS & PNS to influence digestion
Enteric nervous system
the gut’s own system
controls peristalsis, segmentation
ANS speeds or slows it
Mouth
food enters and mastication takes place, aided by saliva
vestibule
lips, cheeks, palate
tongue
vestibule
area between teeth and cheeks
oral cavity proper
internal to teeth
tongue
moves food around and mixes it with saliva to form a bolus
aids in speech production
skeletal muscle covered with mucous membrane
anterior 2/3 of tongue is in oral cavity, posterior 1/3 located in pharynx (attached to hyoid bone)
bumps on anterior 2/3 of the tongue are called papillae; posterior 1/2 has tonsils
Teeth
designed to handle different types of food in different ways
incisors
4 pairs
adpted to cut and shear food