Dalani's Deck: Unit 4 - Gastrointestinal Flashcards
How much of total human body mass is the GI tract?
5%
What are the 5 main functions of the GI system?
- motility
- digestion
- absorption
- excretion
- circulation
What are the layers of the GI system from outermost to innermost including the mucosal layers from outermost to innermost?
serosa, longitudinal muscle, circular muscle layer, submucosa, mucosa: muscularias mucosae, lamina propria, epithelium
What is the serosa’s function?
smooth membrane of thin connective tissue and cells that secrete serous fluid to enclose the cavity and reduce friction between muscle movements
What is the purpose of the longitudinal muscle layer?
contracts to shorten the length of the intestinal segment
What is the purpose of the circular muscle layer?
contracts to decrease the diameter of the intestinal lumen
What innervates the GI organs up to the proximal transverse colon?
celiac plexus
What innervates the descending colon and distal GI tract?
inferior hypogastric plexus
What 4 ways can the celiac plexus be blocked?
- transcrural
- intraoperative
- endoscopic US guided
- peritoneal lavage
Where is the myenteric plexus and what does regulate?
between the smooth muscle layers and regulates the smooth muscle
What does the submucosal plexus do?
transmits information from the epithelium to the enteric and central nervous system to control absorption, secretion, and mucosal blood flow
What 3 layers make up the mucosa?
muscularis mucosa, lamina propria, and epithelium (outermost to innermost)
What does the muscularis mucosa do?
it is a thin layer of smooth muscle that functions to move the villi
What is the lamina propria?
contains the blood vessels and the nerve endings
What is the function of the GI epithelium?
GI contents are sensed, enzymes are secreted, nutrients are absorbed, and waste is secreted
What main system controls the GI tract (both names)?
the autonomic nervous system aka the extrinsic nervous system
Which extrinsic system is primarily inhibitory and decreases GI motility?
The sympathetic extrinsic system
Which extrinsic system is primarily excitatory and increases GI motility?
The parasympathetic extrinsic system
What does the enteric nervous system control?
the independent nervous system which controls motility, secretion, and blood flow
What makes up the enteric nervous system?
the myenteric plexus and the submucosal plexus
What does the myenteric plexus control?
Motility which is carried out by enteric neurons, interstitial cells of Cajal, and smooth muscle cells.
What are the interstitial cells of Cajal also called?
the ICC or GI pacemaker cells
Both the submucosal plexus and the myenteric plexus respond to __________ and ___________ stimulation.
sympathetic and parasympathetic
What is an upper gastrointestinal endoscopy (EGD)?
diagnostic or therapeutic procedure where an endoscope is placed into the esophagus, stomach, pylorus, and duodenum with or without anesthesia