Structure/ Regulation of GI Tract Flashcards
What structures does the GI tract include?
Oral cavity, esophagus, stomach, small and large intestines
What is the term for stomach?
Gastric
What is the term for intestines?
Enteric
What 4 layers of tissue does the does the GI tract wall consist of?
From the lumen outwards - mucosa, submucosa, circular and longitudinal muscular layers, and serosa
What three parts does the mucosa in the GI tract consist of?
Epithelium, lamina propria, muscularis mucosae
What types of epithelial tissue does the GI tract consist of?
Mouth/ anus - stratified squamous epithelium
Rest of GI tract - simple columnar epithelium
What type of junctions connect the epithelial cells in the GI tract?
Tight junctions
What type of tissue does the lamina propria consist of?
Loose areolar connective tissue
What structures does the lamina propria layer contain?
Blood, lymph vessels, glands
What type of muscle does the muscularis mucosae in the GI tract consist of and what does it do?
Smooth muscle - forms the mucosa folds that increase the surface area of the lining of the stomach and intestines
What type of tissue does the submucosa layer consist of?
Dense connective tissue
What are the two smooth muscle layers in the GI tract?
Inner circular and outer longitudinal
What type of tissue is the serosae layer made up of?
Loose connective tissue
The part of the process where large molecules are broken down into their smaller components
Digestion
What are the two control systems the GI tract is regulated by?
- CNS and endocrine system
- Enteric nervous system with intrinsic endocrine/ paracrine component
The enteric nervous system is commonly known as what?
The brain of the gut
What does the enteric nervous system control?
Secretory and motor functions - contains its own pacemaker cells
What 2 plexuses make up the enteric nervous system and what do they do?
- Submucosal plexus - controls secretions and blood flow
- Myenteric plexus - controls movement of GI tract through local reflexes
What is the difference between endocrine and paracrine cells?
Endocrine cells secrete hormones directly into the bloodstream, paracrine cells secrete substances into interstitial fluid which travel by diffusion and affect neighboring cells
What does the endocrine hormone cholecystokinin do?
Inhibits gastric emptying
