Term
|
Definition
| A peptide hormone member of the gastrin family of hormones, secreted by the duodenal mucosa in response to the lipid and protein components of intestinal chyme. Its primary function with Ach is to stimulate emptying of the gall bladder and thebiliary tree |
|
|
Term
|
Definition
A phospholipid in which the organic phosphate is choline, it is thus also known as phosphatidylcholine. Lecithin is a significant component of bile and plays an important role in the formation of biliary micelles |
|
|
Term
|
Definition
| A blind sac component of the large intestine that is continuous with origin of the ascending colon. |
|
|
Term
|
Definition
| A soluble cytosolic enzyme that facilitates the reaction of H2O and CO2 to form H2CO3. It serves as the origin of H+ for gastric acid and HCO3 for secretion of NaHCO3 or exchange with ECF Cl- for secretion of Cl- to activate serous secretions such as that of intestinal fluids |
|
|
Term
| Facilitated transport of carbohydrates |
|
Definition
| The movement of simple sugar molecules (glucose and galactose) across cell membranes through intrinsic membrane protein complexes that simultaneously transport Na+ ions. The Na+ ion concentration gradient energy driving Na+ through the membrane results in the trasport of the sugars against their concentration gradients. |
|
|
Term
|
Definition
| A peptide hormone secreted by the duodenal muosa in response to a decrease in pH of intestinal chyme. The hormone primarily serves to stimulate the secretion of NaHCO3 and fluid by the pancreas, pancreatic ducts, and bile ducts. |
|
|
Term
|
Definition
| A peptide hormone of the secretin family, secreted by L type enteroendocrine cells in response to glucose, protein or lipid in the duodenum and is degraded by dipeptidyl peptidase-4 for a half life of less than 2 minutes. It acts as an incretin (stimulates pancreatic insulin secretion), inhibits pancreatic glucagon secretion and gastrointestinal motility to delay gastric emptying, activates satiety through brain mechanisms and stimulates hepatic glucose synthesis. |
|
|
Term
| Frequency gradient of small intestine |
|
Definition
| A variation in the intrinsic rate of segmentation along the small intestine, beginning in the duodenum with a rate as high as 18/min, gradually decreasing in subsequent segments to about 3/min in the ileum. This gradient serves both mixing actions, and propulsive energy for moving chyme through the small intestine. |
|
|
Term
| "Fasting" motility in nonruminants |
|
Definition
| When the small intestine is relatively empty, segmentation activity begins in the stomach and then in the initial duodenum, in response to an enhanced slow wave activity. This activity sweeps toward the ileum, traversing the small intestine in about 90 to 120 minutes, when it begins again in the stomach. It functions to prevent stasis of chyme within the fasted intestine. |
|
|
Term
| Chemoreceptive center for emesis |
|
Definition
| A circumventricular organ called the area postrema of the medulla. Contains neurons that are sensitive to a variety of plasma born chemicals, such as those produced by microbial infections, and drugs such as digitalis and apomorphine to induce emesis. |
|
|
Term
|
Definition
| A motor act involving relaxation of the anal sphincter, enhanced peristalsis in the descending colon, closure of the glottis and a strong abdominal contraction to raise intra-abdominal pressure. The reflex is initiated by fecal material in the rectum and its effect is to empty the descending colon. |
|
|
Term
|
Definition
| Intrinsic membrane proteins consisting of 7 intramembranous domains, associated with Gi proteins in the cytoplasm that inhibit membrane adenylate cyclase, and sensitive to epinephrine and norepinephrine in the extracellular fluid domains. |
|
|
Term
|
Definition
| A family of peptide hormones, including substance P and neurokinins that have a common N-terminal series of amino acids. They are functional as neurotransmitters and control motility of the intestinal smooth muscle and vascular smooth muscle. |
|
|
Term
|
Definition
| Periodically through the day (generally once or twice) there is a peristaltic movement that moves ascending and transverse colon contents into the descending colon. This activity usually initiates defecation, and places the fresh desceding colonic contents in a segment of the colon where dehydration is a principle function. |
|
|
Term
|
Definition
| A permanent, fixed segmentation motility of the intestine due to the structure of the lamina muscularis. The longitudinal muscle is organized into taenia, and the circular muscle produces regular constrictions. |
|
|
