Exam 1 Flashcards
(335 cards)
Submucosal plexus
Nerve plexus in GI tract, below mucosa
Regulates secretion
Myenteric plexus
Nerve plexus in GI tract between circular and longitudinal muscle
Regulate motility and smooth muscle contraction
Input to enteric plexi
From spinal cord - sympathetic and parasympathetic autonomics
Enteric inputs - proprio and chemoreceptors within mucosa/submucosa
Outputs from enteric plexi
Regulate function of GI tract
Secretion, motility
Sympathetic innervation of GI tract
Directly innervate pancreas, liver, gall bladder, vascular smooth muscle of feed arterioles
General inhibition, vasoconstriction
Parasympathetic innervation of salivary glands
7th and 9th cranial nerves
Increase motor/secretory function
Parasympathetic innervation of GI (not salivary)
Vagus
Secretion and motility
Gastrin: Stimulus, action
Stimulated by peptides, amino acids, stomach distention
Function: Stimulate acid secretion and GI growth
Secretin: Stimulus and action
Stimulus: Duodenal acidity
Action: Pancreatic bicarb secretion
CCK stimulus and action
Stimulus: Fatty acids, amino acids in intestine
Action: Gall bladder contraction, pancreatic enzyme secretion and growth
GIP: Stimulus and action
Stimulus: Glucose, fatty acids in intestine
Action: Insulin release
High levels of CCK stimulate…
Activates motility of stomach and closure of pyloric sphincter
Incretins
GIP
GLP
Insulin secretion, reduced glucagon secretion
GLP-1 inhibits gastric emptying
Gastrin and CCK family overall
Increase intracellular Ca in target cells
Secretin hormone family: Members and physiological function
VIP, GIP, GLP-1
Increase cAMP and AC activity
Hormone concentration and length of intestine relationship
Increased length along GI tract = more hormone
CCK primary location
Intestine
Gastrin primary location
Stomach antrum
Secretin cell primary location
Intestine
GIP secreting cell primary location
Intestine
GLP-1 secreting cell primary location
Small intestine and colon
Pancreatic polypeptide stimulus and action
Stimulus: glucose
Action: decrease pancreatic bicarb and enzyme secretion
Ghrelin
Stimulates appetite
Decrease insulin release
Motilin
Initiates or sensitizes gastric motility
Initiates or sensitizes intestinal motility