Term
| What is the cephalic phase? |
|
Definition
| Seeing and tasting food activates parasym efferent pathway stimulating secretion of gastrin, HCL, and motility. |
|
|
Term
| What is the gastric phase? |
|
Definition
| Amino acids and peptides in the stomach as well as stomach distention and caffeine stim gastrin and HCL |
|
|
Term
| What is the intestinal phase? |
|
Definition
| Distention, acidity, digestive products stim extrinsic and enteric system as well as secretion of secretin, CCK, and GIP |
|
|
Term
| What is the difference between extrinsic and intrinsic (enteric) system? |
|
Definition
| Extrinsic is composed of parasym and sym autonomic nerves, intrinsic is the local neural network of the bowel system. |
|
|
Term
| What controls the secretion of saliva, parasym, sym, or hormones? |
|
Definition
| Parasym facial and glossopharyngeal nerves and Sym T1-3 spinal nerves, but no hormones. |
|
|
Term
| True or False: The frequency of the basal electric rhytym (BER) of the caudad region of the stomach is regulated by neural and hormonal inputs. |
|
Definition
| False, the BER frequency is not regulated by anything, but the frequency of action potential firing during BER plateau is increased by parasym, gastrin, and motilin and decreased by sym activity that hyperpolarizes the membrane potential. |
|
|
Term
| What does CO2 have to do with HCL secretion in the stomach? |
|
Definition
| CO2 and water are changed to HCO3 and H+ inside the cell via carbonic anhydrase, the H+ is excreted via H/K ATPase and HCO3 is excreted basolaterally via a HCO3/CL channel while the Cl is excreted into the lumen to make HCL. |
|
|
Term
| What vitamin is modified by intrinsic factor from parietal cells so that it can be absorbed in the small intestine (ileum)? |
|
Definition
| B12, which is necessary for RBC production. |
|
|
Term
| When you need to vomit what part of the brain do neural inputs act on to induce vomiting? |
|
Definition
| Vomiting center of the brainstem medulla. |
|
|
Term
| What 3 qualities of chyme in the duodenum reduces the rate of gastric emptying? |
|
Definition
| High acidity has neural relflex to close pyloric sphincter, high fat releases CCK, and hyperosmolarity also closes pyloric sphincter |
|
|
Term
| What is a migrating myoeletric complex and when does it occur? |
|
Definition
| It occurs during fasting when motilin is released and it clears contents of stomach and small intestine and maintains a low bacterial count in large intestine. 1x/90min. |
|
|
Term
| How does the release of secretin and CCK from the small intestine affect the pancreas? |
|
Definition
| Both hormones enter the bloodstream which increase HCO3 and enzyme secretion, respectively. |
|
|
Term
| What percent of bile salts, which solubilize fats, are recycled? |
|
Definition
|
|
Term
| When referring to GALT, what is a Peyer’s patch? |
|
Definition
| Lymphoid tissue in the small intestine (concentrated in the terminal ileum) that contains 5 lymphoid follicles that accumulate T/B/Macrophage cells and are covered by mucosal epithelium. |
|
|
Term
| How do intraepithelial lymphocytes and epithelial cells function in GALT? |
|
Definition
| IELs are located in the gut and lamina propria and consist of CD8 T cells that secrete cytokines, and epithelial cells act as antigen presenting cells. |
|
|
Term
| There are diffuse accumulations of lymphoid cells in GALT, what two cell types predominate? |
|
Definition
| Intraepithelial lymphocytes and lamina propria cells (mononuclear cells, IgA producing plasma cells, mast cells, etc.) |
|
|
Term
| What is the role of IgA in the GALT? |
|
Definition
| It is a non-inflammatory molecule that prevents molecule uptake and can also expel molecules from cells. |
|
|
Term
|
Definition
| Suppression of immune system despite the presence of antigen-activated mucosal immune response and production of gut IgA |
|
|
Term
| What does a food allergy have to do with IgE? |
|
Definition
| When there is a breakdown of oral tolerance, the body makes IgE instead of IgA that bind with food antigen. The IgE’s then bind with mast cells in lamina propria which, once triggered upon second ingestion of allergen, release chemicals that increase chloride secretion and diarrhea. A mucosal response can trigger colorectal distention. |
|
|
Term
| How are zymogens activated? |
|
Definition
| Pancreas releases trypsinogen that is activated by enterokinase in intestinal lumen and then becomes trypsin; trypsin activates all other zymogens. |
|
|
Term
| If a baby gets diarrhea when they drink breast milk, what affliction do they have? |
|
Definition
| Glucose-Galactose malabsorption |
|
|
Term
| Why does a person’s breath hydrogen increase if they have lactase deficiency? |
|
Definition
| Colonic bacteria metabolize the uncoverted lactose and release H2. |
|
|
Term
| What percent of fluid is absorbed by the GI tract? |
|
Definition
| 99%, 82% from small intestine, and rest from large intestine. |
|
|
Term
| Where is the majority of final carb digestion occurring in the GI? |
|
Definition
|
|
Term
| True or false: A healthy adult consumes 250g of carbs, 50g of complete protein, and 60-160 grams of fat. |
|
Definition
|
|
Term
| Which molecules does lactase, amylase, sucrase, and glucoamylase create in its final product? |
|
Definition
| Glucose, fructose, and galactose |
|
|
Term
| What key pancreatic enzyme allows for the activation of all other digestive enzymes? |
|
Definition
| Enterokinase in duodenum brush border; it activates trypsin which activates chymotrypsin, elastase, and carboxypeptidases |
|
|
Term
| How are glycerol, short/medium chain fatty acids absorbed differently than micelles made of cholesterol, long chains, and monoglycerides? |
|
Definition
| First group passes through enterocytes and enter capillary, second group absorbs through SER then golgi as a cholymicron then enter lymphatic capillary called lacteal |
|
|
Term
| What is the main source of 5-HT in the GI? |
|
Definition
| Enterochromaffin (EC) cells and internuerons make up 95% of the body's serotonin; EC is the major source in the intestine |
|
|
Term
| What is the serotonin (5-HT) precursor that can be ingested? |
|
Definition
| Tryptophan; most other 5-HT sources are metabolized before entering blood |
|
|
Term
| How is 5-HT serotonin metabolized? |
|
Definition
| Enterocytes only on the intestinal epithelium transport it into cell via Serotonin Reuptake Transporter (SERT) and metabolized to 5-HIAA and then is pissed out; or metabolized by lungs, liver MAO enzyme to 5-HIAA |
|
|
Term
| There are 4 places in the periphery that serotonin is located - lungs, blood platelets, plasma, EC cells in gut - where is the content high or low? |
|
Definition
| Lungs/plasma= low, EC cells/platelets= high |
|
|
Term
| True or False: platelets and lungs maintain high blood levels of 5-HT by adding it to the circulation. |
|
Definition
| False, they maintain low levels in the blood since platelets store it to use for aggregation and the lungs metabolize it. Therefore peripherap 5-HT has a major role in regulation of GI motility. |
|
|
Term
| What is the difference in communication effects between 5-HT3 and 5-HT4 receptors? |
|
Definition
| Both receptor types increases IPAN (intrinsic primary afferent neurons) firing of Ach at the synapse with myenteric neurons when EC cells are triggered, but only 5-HT3 receptors also increase communication to the CNS |
|
|
Term
| True or false: The brain-gut connection illustrates that both a suppressed immune system and IBS can be attributed to emotional state. |
|
Definition
|
|
Term
| Describe the route of transmission for Hep A, B, and C. Also describe if there is a chronic carrier state |
|
Definition
| Hep A - oral-fecal, self-clearing; Hep B sexual, vertical, blood transmission, more common with MSM, self-clearing; Hep C blood exposure, not sure if sexually transferred, chronic condition. |
|
|
Term
| True or False: women are more likely to suffer alcoholic cardiomyopathy and progress to alcoholic liver disease earlier than men. |
|
Definition
|
|
Term
| Histamine stimulation can be induced by both a neuronal pathway and hormonal pathway via the ECL cell, describe which molecule is used for each. |
|
Definition
| Ach is used to activated muscarinic receptors to move Ca mediated exocytosis on the ECL; Gastrin will activate CCK2 receptors on ECL as well |
|
|
