exam 3 Flashcards
what is the location of the feeding center
lateral
what is the location of the satiety center
ventromedial
what are the effects of insulin on the feeding center
inhibition
what are the effects of feeding on the satiety center
activation
effects of glucagon on the feeding center
activation
effect of glucagon on the satiety center
inhibition
what is the relationship between blood glucose levels and activity for the feeding center
inverse
what is the relationship between blood glucose levels and activity for the satiety center
direct
effect of release of CCK on feeding center
inhibition
effect of release of CCK on satiety center
activation
what are the 4 layers of the GI tract
mucosa, submucosa, muscular, serosa
describe the mucosa layer with composition and function
composition: epithelium
function: absorption and secretion
describe the submucosa layer with composition and function
composition: connective tissue
function: blood, nerve, and lymph supply
describe the muscularis layer with composition and function
composition: smooth muscle
function: motility
describe the serosa layer with composition and function
composition: connective tissue
function: reduction of friction during muscle contractions
what are the 2 plexuses of the enteric nervous system
submucosal plexus and myenteric plexus
submucosal plexus (location and controls)
located in submucosal layer and controls secretions
myenteric plexus (location and controls)
located between 2 layers of smooth muscle in muscularis and controls motility of muscularis layer
describe the importance of serotonin levels in the digestive system
serotonin is a neurotransmitter of EC cells of the mucosal layer. it increases activation of the muscularis layer during peristalsis.
what would be a better drug to treat IBS, a drug that increased side effects of serotonin or one that decreases side effects
a more effective drug would be one that decreases serotonin effects to decrease smooth muscle contractions of the muscularis
describe the importance of bile
a secretion of the liver; stored in the gall bladder; important in the mechanical digestion of lipids in the small intestine; increases efficiency of pancreatic lipase
describe the importance of gastrin
hormone produced by G cells of the stomach; increases secretions and motility of the stomach; initiates a positive feedback loop in the stomach
pancreatic lipase
enzyme important in the chemical digestion of lipids in the duodenum
pepsin
enzyme important in the chemical digestion of proteins in the stomach
salivary amylase
enzyme important in the chemical digestion of carbs (specifically starches) in the mouth
what are the 3 phases of the control of the digestion
cephalic, gastric, intestinal
describe activity and a substance that causes the change in the stomach for cephalic
activity of the stomach increases and the substance is ACh
describe activity and a substance that causes the change in the stomach for gastric
activity of the stomach increases and the substance is gastrin
describe activity and a substance that causes the change in the stomach for intestinal
activity of the stomach decreases and the substance is GIP
what is the importance of carbonic anhydrase in the stomach
carbonic anhydrase is an enzyme that drives the reaction to the right, which allows for production of acid in the stomach
what is THE chemical equation
CO2 + H2O <-> H2CO3 <-> H + HCO3
describe the effect of carbonic anhydrase activity on each of the phases and the substance
- cephalic: increasing; ACh
- gastric: increasing; gastrin
- intestinal: decreasing; GIP
what is the name of the stomach cell with he highest carbonic anhydrase
its highest in the cells of the stomach that secrete acid in the parietal cells
how does the pH of the stomach affect carbonic anhydrase activity
carbonic anhydrase activity of parietal cells would be directly proportional to the pH of the stomach
what is the importance of pepsinogen
pepsinogen is the active form of pepsin (the protein important in the chemical digestion of proteins in the stomach)
what cell produces pepsinogen
pepsinogen is produced by chief cells of the stomach
what is the pH that pepsinogen requires for activation
pepsinogen is converted to pepsin in the presence of acid/low pH
what does pepsinogen require activation
because its produced in the inactive form so that it doesn’t digest the walls of the stomach
importance of triglycerides
digested in the small intestine
importance of bile
bile is a substance that mechanically digests lipids, emulsifying fats, and increasing the surface area for the enzyme pancreatic lipase
importance of pancreatic lipase
enzyme that is important for chemical digestion of lipids in the small intestines
importance of micelles
transport the digestion products of pancreatic lipase to the walls of the small intestine for their absorption
importance of chylomicrons
transport triglycerides from their site of absorption in the small intestine through the lymph and into the blood and on to the adipose tissue
what hormone is present in absorptive state
insulin
what hormone is present in post absorptive state
glucagon
primary fuel source for most tissues in absorptive state
glucose
primary fuel source for most tissues in post absorptive state
fats
primary fuel source for nervous tissue in absorptive state
glucose
primary fuel source for nervous tissues in post absorptive state
glucose
timing for abortive state
immediately following a meal
timing for post absorptive state
hours after a meal
relative blood pH for absorptive state
basic
relative blood pH for post absorptive state
acidic
anabolism
production of polymers from monomers (=synthesis reactions); occurs more during absorptive state
catabolism
production of monomers from polymers (=breakdown reactions); would occur more during the post absorptive state
during pregnancy would the fetus be more in the absorptive state and post absorptive state
the fetus would be in the absorptive state and the mother would be in the post absorptive state
why is it common for pregnant women to develop gestational diabetes
since insulin is the hormone of the absorptive state pregnant women can develop gestational diabetes which would ensure that they are not in the absorptive state
what is the importance of acetyl coenzyme A to energy production by cells
its a chemical intermediate that enters the Krebs cycle and ultimately ending in oxidative phosphorylation in the mitochondria
describe the affect of acetyl coenzyme a levels on anabolism and catabolism
- anabolism: when acetyl CoA levels are high lipids are anabolized
- catabolism: when acetyl CoA levels are low all nutrients are catabolized
describe the most likely effect of insulin and glucagon on acetyl coenzyme A
blood glucose levels are directly proportional to cellular acetyl CoA levels. insulin should raise acetyl CoA levels and glucagon should lower acetyl CoA levels
what are the 4 mechanisms of heat exchange
conduction, convection, evaporation, radiation
conduction
heat transfer between solids; little importance
convection
heat transfer in fluids; importance is directly related to wind speed
evaporation
heat transfer caused when water changes state from a liquid to a gas; only mechanism for heat loss when air temp exceeds body temp
radiation
heat transfer through waves; largest source of heat transfer; in summer people wear fewer clothes in order to increase heat loss through convection and evaporation; in winter people wear more clothes in order to decrease heat loss through convection
describe skin thermoreceptors and the core thermoreceptors
- skin receptors are less sensitive (since skin temp can vary widely); in skin there are more cold thermoreceptors than warm thermoreceptors
- core thermoreceptors are more sensitive; in the core there are more warm thermoreceptors than cold thermoreceptors
