endo test 3 - GI hormones part 1
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114 terms
Terms | Definitions |
|---|---|
 nervous system and endocrine systems | what are the two systems that have control over GI functions? |
| hormones are synthesized within the GI tract by cells scattered in the epithelium of stomach and SI | where are hormones most important in controlling digestive function synthesized? |
| enteric endocrine system | what are the endocrine cells and hormones they secrete in the epithelium of the stomach and SI referred to as? |
| brain | where are most GI hormones synthesized? |
| tube running from the mouth to the anus. tube acts as a disassembly line breaking down large macromolecules into smaller molecules that can be absorbed across the wall of the tube and into the circulatory system for dissemination around your body | describe the digestive system |
| macomolecules - proteins, fats, starch micromolecules - amino acids, fatty acids, glucose | what are some macromolecules that the digestive system breaks down? what the the resulting micromolecules? |
| salivary glands, liver, and pancreas | what are some accessory digestive organs that help the digestive tube? |
| secretion, absorption, motility | what are the three fundamental processes that take place in the digestive system? |
| delivery of enzymes, mucus, ions and the like into the lumen and hormones into blood | what is the secretion part of the digestive system? |
| transport of water, ions, and nutrients from the lumen, across the epithelium and into the blood | what is the absorption part of the digestive system |
| contractions of smooth muscle in the wall of the tube that crush, mix, and propel its contents | what is the motility part of the digestive system? |
| digestive system's own nervous and endocrine systems AND the CNS AND endocrine organs (like the adrenal gland) | where do messages that control digestive function come from? |
| small fermentation vats with little ability to utilize cellulose | how would the digestive system of a cat look? |
| massive fermentation vats that allow them to efficiently utilize cellulose | how would the digestive system of a goat look? |
| yes | do carnivores have the simplest type of digestive system? |
| humans - more extensive large intestine; cows (ruminants) - large set of forestomachs | how would a human's or a cow's digestive system differ from a carnivore? |
| foodstuff broken down mechanically and saliva added as a lubricant or could contain amylase in some species | what does the mouth do in the digestive system? |
| a simple conduit between mouth and stomach | what does the esophagus do in the digestive system |
| enzymatic digestion of proteins and foodstuffs are reduced to liquid form | what does the stomach do in the digestive system? |
| center of metabolic activity. provides bile salts to small intestine that aid in digestion and absorption of fats | what does the liver do in the digestive system |
| provides potent mixture of enzymes to the small intestine which aid in the digestion of fats, carbohydrates, and protein | what does the pancreas do for the digestive system? |
| final stages of chemical enzymatic digestion occur and where almost all nutrients are absorbed | what does the small intestine do for the digestive system? |
| absorbs water, bacterial fermentation takes place and feces is formed | what does the large intestine do for the digestive system? |
| stomach and proximal small intestine contain a small number of microbes because of gastric acid, the colon is filled with microbes with anaerobes | where are the most bacteria amounts found in the digestive system? the fewest amount? |
| ileum | what is the transitional zone in the digestive system called where theres both aerobic and anaerobic bacteria? |
| yes | is the GI tract sterile at birth? |
| 3 to 4 weeks of age | how long does it take a newborn to have a mature microbial flora in their GI tract? |
| germ-free rats have a cecum 10x the size of a conventional rat | would a germ-free rat have a smaller/larger cecum than a conventional rat? |
| deoxycholic acid | what do bacteria in the intestinal lumen convert cholic acid to? |
| yes | do SI bacteria have a role in sex steroid metabolism? |
| digest carbohydrates, proteins, and lipids important in herbivores (cellulose) | what do large intestine bacteria do? |
| brain gut peptides | what is another name of classical GI hormones? |
| gastric | hormone that stimulates gastric acid secretion and proliferation of gastric epithelium |
| presence of peptides and amino acids in gastric lumen | what causes gastrin to be released? |
| cholecystokinin | what hormone stimulates secretion of pancreatic enzymes and bile from the gall bladder? |
| presence of fatty acids and amino acids in the small intestine | what stimulates cholecystokinin release? |
| secretin | what hormone stimulates secretion of water and bicarbonate from the pancreas and bile ducts? |
| acidic pH in the lumen of the small intestine | what causes secretin to be secreted? |
| ghrelin | what hormone is a strong stimulant for appetite and feeding and also serves as a stimulator for GH secretion? |
| not clear, but secretion peaks prior to feeding and diminishes with gastric filling | what causes ghrelin to be secreted? |
| motilin | what hormone stimulates housekeeping patterns of motility in the stomach and small intestine |
| secretion is associated with fasting | what causes motilin to be secreted |
| gastric inhibitory polypeptide | what hormone inhibits gastric secretion and motility and potentiates release of insulin from beta cells in response to elevated blood glucose concentration |
| presence of fat and glucose in the small intestine | what causes gastric inhibitory polypeptide to be secreted? |
| synthesized in G cells which are located in gastric pits, in the antrum region of the stomach | where is gastrin synthesized? |
| binds to receptors found mainly on parietal and enterochromaffin-like cells | where are the receptors that gastrin binds to found? |
| mucous cells, parietal cells, chief cells, G cells | what are the 4 major types of secretory epithelial cells that cover the stomach, gastric pits, and glands? |
| mucous cells | what cell secretes an alkaline mucus that protects the epithelium against shear stress and acid |
| parietal cells | what cells secrete hydrochloric acid |
| chief cells | what cells secrete pepsin |
| pepsin | what is the enzyme secreted by chief cells that has proteolytic activity? |
| g cells | what cells secrete gastrin? |
| gastrin-34 (big gastrin) | what is the predominant circulating form of gastrin? |
| gastrin-14 (minigastrin) | what is the form of gastrin that has full biologic activity? |
| pentagastrin | what is the 5 C-terminal amino acids of gastrin called? |
| pentagastrin | where is the full bioactivity preserved in gastrin? |
| cholecystokinin | what other hormone has the same 5 C-terminal amino acids as gastrin? |
| CCK-B receptor | what is another name of the gastrin receptor? |
| increase in intracellular calcium, activation of protein kinase C, and production of inositol phosphate | what does the binding of gastrin to CCK-B stimulate? |
| G-protein coupled receptor | what type of receptor is CCK-B? |
| gastrin | compounds in coffee, wine, and beer are potent stimulators for the secretion of what hormone? |
| secretion is inhibited when the lumenal pH of the stomach becomes less than 3 | what causes the secretion of gastrin to be inhibited? |
| the immunoneutralization of gastrin lead to the blockage of acid secretion in response to intragastric administration of peptides | immunoneutralization of gastrin in canine species showed what? |
| enterochromaffin-like cells (ECL) | what is the most important target of gastrin in regards of regulating acid secretion? |
| histamine release, histamine binding to H2 receptors on parietal cells, full blown acid secretion | what does gastrin binding to receptors on enterochromaffin-like cells stimulate? |
| stimulate mucosal development and growth in the stomach | besides acid secretion, what other role does gastrin play in gastrointestinal function? |
| humans with hypergastrinemia show gastric mucosal hypertrophy | what support shows gastrin promotes gastric mucosal growth? |
| CCK receptors | what receptors do gastrin bind to stimulate pancreatic acinar cells? |
| regulate gastric motility | what effect does gastrin have when stimulates pancreatic acinar cells? |
| stimulate pancreatic acinar cells | how does gastrin regulate gastric motility |
| excessive secretion of gastrin | what is hypergastrinemia |
| zollinger-ellison syndrome | what disease does hypergastrinemia cause? |
| disorder causing tumors in the pancreas and duodenum and ulcers in the stomach and duodenum. excessive gastrin causes too much acid in the stomach. | what is zollinger-ellison syndrome? |
| gastrin--secreting tumors in the pancreas or duodenum | what is the most common cause of hypergastrinemia? |
| MEN1 | what genetic disorder is associated with zollinger-ellison syndrome? |
| blood test for levels of gastrin and gastric acid. check for ulcers by endoscopy | how do physicians diagnose zollinger-ellison syndrome? |
| medication to reduce production of stomach acid. proton pump inhibitors that suppress acid production. H2 blockers | what is the primary treatment for zollinger-ellison syndrome? |
| cimetidine, famotidine, ranitidine | what are the names of H2 blockers used to treat zollinger-ellison syndrome |
| surgery to remove ulcers or remove tumors in the pancreas or duodenum | what are secondary treatment options for zollinger-ellison syndrome? |
| neurons in the enteric nervous system and is widely abundant in the brain | where is cholecystokinin (CCK) produced? |
| CCK-8 | what form of CCK has full biologic activity? |
| the tyrosine 7 residues from the end is sulfated | how are CCK peptides activated for activity? |
| CCKA and CCKB | what are the two receptors for CCK? |
| pancreatic acinar cells | where are CCKA receptors found? |
| brain and stomach | where are CCKB receptors found? |
| 1-release of digestive enzymes from the pancreas into the duodenum 2-contraction of the gallbladder to deliver bile into the duodenum | elevated blood concentrations of CCK has what 2 effects? |
| satiety (lack of hunger) | injection of CCK into the brain of lab animals caused what? |
| cholecystokinin | what is the most abundant neuropeptide in the CNS? |
| autoimmune polyglandular syndrome, malabsorption syndrome, similiar to pancreatic exocrine insufficiency | what syndrome is CCK deficiency linked with? |
| CCK | anxiety and schizophrenia are disorders that could be linked to the lack of what hormone/hormne's receptor |
| pancreas | what is the principal target of secretin? |
| secrete bicarbonate-rich fluid to the duodenum through pancreatic duct | what does the pancreas do in response to secretin? |
| base serving to neutralize acid. prevents acid burns and establishes a pH conducive to the action of other digestive enzymes. secretin | what is bicarbonate? what is its purpose? what enzyme causes it to be released? |
| bile duct cells | what other cells besides pancreatic cells respond to secretin? |
| no | are there any disease states associated with secretin? |
| an n-octanoic acid binds to one of its amino acids | what modification is necessary for ghrelin activity? |
| epithelial cells lining the fundus of the stomach, also found in the placenta, kidney, pituitary, and hypothalamus | where are the cells found that synthesize ghrelin? |
| hormone secretagoue receptor (GHS-R), anterior pituitary, ghrelin | what is the name of the receptor that secretes GH? where is it found? what is the natural ligand for the receptor? |
| 1-stimulation of GH secretion 2-regulation of energy balance | what 2 biologic activities are associated with ghrelin? |
| ghrelin acts on hypothalamic feeding centers which increases hunger. ghrelin also suppresses fat utilization in adipose tissues | how does ghrelin regulate energy balance? |
| ghrelin | what hormone stimulates gastric emptying and has a variety of positive effects on cardiovascular function? |
| lowest right after a meal and highest right before a meal | when are blood concentrations of ghrelin the highest? when are blood concentrations of ghrelin the lowest? |
| ghrelin concentrations in blood are higher in a lean person compared to an obese person | how do ghrelin blood concentrations compare in lean and obese people |
| higher than normal ghrelin levels in plasma | patients with anorexia nervosa have what kind of levels of ghrelin compared to a normal person |
| prader-willi syndrome | what disease is linked with exceptionally high levels of ghrelin? |
| absence of segment 11-13 on the long arm of the paternally derived chromosome 15 | what causes prader-willi syndrome? |
| mental retardation, decreased muscle tone, short stature, emotional lability, and insatiable appetite | what are the characteristics of prader-willi syndrome? |
| Angelman syndrome | when segment 11-13 is missing on the maternal chromosome 15, what disease develops? |
| genomic imprinting | when the expression of a gene depends on whether it is inherited from the mother or father, what is that called? |
| DNA methylation | what mechanism is involved in genomic imprinting? |
| small ribonucleoprotein N (SNRPN) | what do the genes found in the Prader-willi syndrome code for? |
| mRNA processing | what is small ribonucleoprotein N involved in? |
| babies - floppy, poor muscle tone boys - undescended testicles short stature, poor motor skills, weight gain, underdeveloped sex organs, mental retardation, almond shaped eyes | what are the physical features of people with prader-willi syndrome? |
| growth hormone and exercise | how is prader-willi syndrome treated? |
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