Lect 1: Overview Flashcards
What are the epithelial cells called in the lower GI tract
Enterocytes
When does “food” become “chym”?
when it enters the stomach
How long do enterocytes usually exist?
3-5 days
What are the two intrinsic nervous systems that inneravate the GI tract?
Submucosa and myonteric
What level of GI tissue is the submucosal innervation?
Between the Submucosa and the circular muscle
What level of GI tissue is the myonteric innervation?
Between the circular and longitudinal muscle layers
What does activation of the submucosal plexus induce?
Secretion
What is the function of the myonteric plexus?
Contractions
What are the controlers of the enteric system?
ANS and hormonal
Where are the only places you get voluntary muscle control?
Mouth and pharanx
What are the invaginations in the lumenal side of the intestinal wall?
Crypts of lieberkuhn
Where in the GI tract are crypts of lieberkuhn located
Just in the small and large intestine
What is the only nutrient that doesn’t do a “first pass” through the portal vein/ liver?
Lipids
where is most of the fluid absorbed in the digestive tract?
small intstine
What are the enteric nervous system branches?
myenteric and submucosal
What do the parasympathetics travel through and what do they innervate?
The vegus nerve to everything through the transverse colon and pelvic nerve to the descending colon and rectum
What are the sympathetic innervations of the GI Tract?
celiac, superior mesentary, inferior mesenteric, hypogastric plexus
What does digestion?
enzymes, mechanical contractions, and HCl
What provides protection from pathogens?
HCl, IgA, opsonins WBC’s
What function does motility provide?
propels and mixes chyme
What function do secretion provide?
buffering, mucus lining for protection and lubrication, hormone signaling and enzymatic digestion
What are the two places for storage?
Stomach and colon
What actions does the parasympathetics have on the tract?
Pro-digestion, movement, secretions
What actions does the sympathetics have on the tract?
Stop functions
