Normal fxn and Motility Flashcards
What do gastric parietal cells produce and secrete?
HCL and Intrinsic Factor
What do gastric chief cells secrete?
Pepsinogen
How is pepsinogen (zymogen) activated to pepsin?
Low pH
Which hormone activates parietal cells?
Gastrin
Where is cholecystokinin (CCK) secreted?
Small intestine
What does CCK do?
Stimulates release of pancreatic hormone and contraction of gall bladder
Where is secretin secreted?
Small intestine
What does secretin do?
Stimulates release of bicarbonate-rich fluid from pancreas
Capillaries of the intestinal villi end up in the hepatic portal system whereas lacteals end up in ___________.
Larger lymphatics which proceed to bloodstream via the thoracic duct.
What are Peyer’s patches?
Groups of lymphatic nodules in GI tract
What are M cells of the GI tract?
Specialized epithelial cells that function as antigen-uptake cells.
Which nerve is responsible for most parasympathetic actions on the GI tract?
Vagus nerve
What is the purpose of Migrating Motor Complexes (MMCs)?
Housekeeping role - sweep gut. Occur in fasting state every ~90min.
Describe basic electrical rhythm (BER) aka slow waves of the intestines
Myogenic spontaneous rhythmic waves of depolarization at a frequency of about 12/min. These depolarizations do not cause contractions.
What happens when ACh acts on intestinal myocytes?
Action potential and contractions occur at a rate set by BER.
What is the purpose of segmentation movement in the intestine?
To help ensure proper digestion and absorption of all the luminal contents.
What is the effect of gastrin on peristaltic contraction and pyloric tone?
Increases contraction and decreases tone
What is the effect of cholecystokinin on gastric motility?
Decreases motility
What is the role of the hormone motilin?
Released from small intestine and initiates MMCs
What are the two most prominent patterns of motility in the colon?
Segmentation movements and mass movements
