Module 17: The Digestive System Flashcards
Mesentery
A fold of peritoneum that attaches the small intestine to the posterior abdominal wall
Mesocolon
A fold of peritoneum that attaches the colon to the posterior abdominal wall
Falciform ligament
A fold of peritoneum that attaches the liver to the anterior abdominal wall and diaphragm
Also separates the liver into two lobes
Greater omentum
Also called the “fatty apron”
Hangs from the stomach and covers the transverse colon and the small intestine
Lesser omentum
A fold of peritoneum that suspends the stomach and the duodenum from the liver
Mucosa
Inner layer of alimentary canal
Protection
Secretion of enzymes, mucus, and hormones
Absorption of nutrients
Layer of smooth muscle cells produces movements of the mucosa
Pulls the mucous membrane of the small intestine into folds (called plicae circularis) increasing surface area
Submucosa
Connective tissue that binds the mucosa to the muscularis
Contains blood and lymphatic vessels, lymph nodules, and nerve fibers
Muscularis
Consists of an inner layer of circular smooth muscle and an outer layer of longitudinal smooth muscle
Mixes (segmentation) and propels (peristalsis) food and water along the digestive tract
The circular layer of smooth muscle form valves (sphincters) in specific areas of the tract
Serosa
Visceral peritoneum
Consists of areolar connective tissue covered with simple squamous epithelium
Protection
Amylase
Enzyme secreted by parotid glands
Produced in pancreas
Helps digest starch
Cardiac sphincter
Lower esophageal sphincter
Controls passage from esophagus to stomach
Oblique layer
Third layer of digestive tract
Only in stomach
Provides churning motion
Pyloric sphincter
Valve between stomach and duodenum
Mucous neck cells
Secrete mucous which is acidic and very different from the protective mucous secreted by the surface epithelium
Chief cells
Secrete mainly the enzymes pepsinogen (breaks up proteins) and some lipase (breaks up fats)
Parietal cells
Secrete hydrochloric acid (maintains the pH of stomach contents and kills bacteria) and intrinsic factor (necessary for the absorption of vitamin B12)
Enteroendocrine cells
Release chemical messengers that stimulate the release of gastrin
Regulate gastric juice secretion
Bile
From the liver, stored in the gallbladder
Helps digest fats
Lipase
From the pancreas
Helps digest fats
Proteases
From the pancreas
Help digest proteins
Crypts of Lieberkuhn
Glands in small intestine
Screte enzymes that chemically digest proteins and carbohydrates
Peyer’s Patches
Clumps of lymphoid follicles found in abundance toward the end of the small intestine
Ileocecal valve
Connects the ileum to the first part of the large intestine
Prevents feces from reentering the small intestine
Functions of the large intestine
Absorption of water and electrolytes
Synthesis of vitamin K and certain B vitamins by intestinal bacteria
Elimination of feces (defecation)
