Flashcards in GI Physiology Deck (44):
Inner most layer of GI wall composed of epithelial cells specialized for absorption and secretion.
Layer of GI wall that consists of collagen, elastin, glands, and blood vessels
Layers of GI wall that provides motility for GI tract
Circular and Longitudinal Smooth Muscle
Outer most layer of GI wall
breaking food in small particles so they are easily broken down by enzymes. occurs in the mouth and stomach
Enzymes in mouth that helps digest carbs and lipids
amylase (carbs) and lipase (lipids)
First step of swallowing
What is different about the layers of the esophagus compared to the rest of the GI tract?
Enzymes that breakdown proteins in the stomach
pepsin and peptidase
What are the three phases of digestion?
cephalic, gastric, intestinal
Stimulates the release of pancreatic juice and weak contractions of the gallbladder during the cephalic and gastric phases of digestion
What induces the release of cholecstokinin?
fatty, protein-rich chyme
What induces the release of secretin by the enteroendocrine cells of the duodenal wall?
What induces the release of pancreatic juice?
CCK and secretin
Required for the absorption of B12
Protects gastric mucosa from HCl
Cells found in the body of the stomach that secrete pepsinogen
Cells found in the body of the stomach that secrete HCl and intrinsic factor
Secreted by G cells in stomach in response to eating. Stimuli include proteins, distention of stomach, and vagal stimulation
Promotes H+ secretion by gastric parietal cells. Stimulates growth of gastric mucosa
Released from vagus nerve. Binds to receptors on parietal cells. Produces H+ secretion by parietal cells. Atropine blocks muscarinic receptors on parietal cells
Released from mastlike cells in gastric mucosa. Binds to H2 receptors on parietal cells. Produces H+ secretion by parietal cells
Most common cause of upper GI bleeding?
Type of motility where circular muscle contracts sending chyme in both directions. Intestine then relaxes allowing chyme to merge back together
Type of motility where longitudinal muscle contracts propeling chyme along small intestine. Simultaneously, portion of intestine caudal to bolus relaxes
Controls contractile, secretory, and endocrine functions of GI tract. Sends information directly to smooth muscle, secretory, and endocrine cells
Name for the numerous openings of gastric mucosa where the gastric glands empty into
Largest internal organ
Supplies majority of blood supply to the liver. Brings venous blood rich in nutrients from digestive tract. High blood flow
hepatic portal vein
Name of structures where hepatocytes are in contact with blood in the liver. They fxn as capillaries and are arranged to form functional units (lobules)
Found in people who abuse alcohol because alcohol suppresses citrate cycle and thereby impairs gluconeogenesis from aminoacids.
What is the majority of cholesterol in the liver converted into?
Necessary for digestion and absorption of lipids in small intestine. Emulsify lipids to prepare them for digestion
Detectable when the total plasma bilirubin > 2mg/dl
good diagnostic test for obstructive jaundice
What is the pathophysiologi mechanism behind the development of varices and ascites associated with cirrhosis?
Cirrhosis leads to scar tissue which can obstruct blood and bile flow. Obstruction of hepatic venous blood flow can increase pressures
Main duct (Wirsung) runs the entire length of pancreas. Joins CBD at the ampulla of Vater
Acts on the acid producing parietal cells and indirectly decreases stomach acid production by preventing release of gastrin, secretin and histamine.
only digestive enzyme secreted by the pancreas in an active form
functions optimally at a pH of 7. hydrolyzes starch and glycogen to glucose, maltose, maltotriose, and dextrins
Finger-like projections of the small intestinal mucosa
Tiny projections on luminal membrane of each intestinal cell. Give the apical region striated appearance called brush border
primary site for the removal of water and electrolytes and the storage of feces
Tubular glands located in the mucosa of the large intestine that are responsible for mucus secretion