GIT Flashcards
how is water intake regulatedÉ list the 4 mechanisms
- increasing plasma osmolarity
- decreased plasma volume
- dry mouth and throat stimulate thirst
- prevention of over hydration
When plasma osmolarity increases, which of the following responses is most likely to occur?
A) Vasopressin (antidiuretic hormone) released, promoting water retention in kidneys.
B) Vasopressin (antidiuretic hormone) inhibited, increasing water excretion by kidneys.
C) Renin released, leading to decreased thirst and water excretion in kidneys.
D) Aldosterone released, causing water loss and decreased plasma volume.
(High plasma osmolarity stimulates osmoreceptors in the hypothalamus, triggering vasopressin release to retain water.)
What is the physiological response to a significant decrease in plasma volume?
A) Stimulation of baroreceptors in kidney afferent arteries, leading to activation of the renin-angiotensin system.
B) Inhibition of baroreceptors in kidney afferent arteries, leading to decreased renin release and water loss.
C) Suppression of the renin-angiotensin system, causing vasodilation and reduced sodium retention.
D) Direct activation of osmoreceptors in the hypothalamus, leading to aldosterone inhibition.
(A significant drop in plasma volume triggers baroreceptors in kidney afferent arteries, stimulating renin release, which activates the renin-angiotensin system to restore blood volume and pressure.)
renin angiosensisn system activates angiotensin 2, which stimulates thirst
How does the body prevent over hydration? Chose the BEST answer
A. Drinking stops when the tummy is full
B. Drinking is stopped and Mediated by baroreceptors
C. Drinking stops before water is absorbed by the GIT
D. Drinking is mediated by a stimulus in the mouth, throat, and GIT
Drinking stops when water is not yet absorbed by the git and is mediated by a stimulus in the mouth, throat and GIT
Describe the pathway of regulating hunger
- Taking in food
- Adipose tissue increases fat deposition and leptin
- Increase of leptin in the plasma
- Leptin signals to the hypothalamus
- Hypothalamus inhibits neuropeptide y
- Food intake decreases and metabollic rates increase
- Negative feedback occurs (due to decreased fat deposition)
(think of it like leptin made reservations for a party room and nueropeptide y is being bad and wont leave, so leptin brings its gang and tells the hypothalamus to kick out nueropeptide y)
What are the 4 anorexigenic factors?
- leptin (from adipose tissue)
- insulin (from pancrease)
- peptide YY (intestines)
- Melanocortin (from hypothalamus)
What induces water intake?
- low plasma volume
- increases plasma osmolarity
- dry mouth and throat
How does cystic fibrosis affect the pancreas and digestion?
A. It increases bicarbonate secretion, enhancing enzyme activation.
B. It leads to thickened mucus that blocks pancreatic ducts, reducing enzyme delivery to the intestine.
C. It stimulates excessive bile acid production, causing fat malabsorption.
D. It decreases HCO3 and H2O secretion, causing enzymes from ducts to not get flushed properly to the intestines
b and d
what are the four inactive proteases secreted by the pancreas?
- trpsinogen
- chymotrypsinogen
-proelastase - pro-carboxy peptidase A and B
what are the 4 major proteases activated by?
trypsinogen activated by enterokinase
chymotrypsinogen, pro-elastase and por-carboxy peptidase A and B are activated by trypsin
what are the active proteases in the pancrease?
- trypsin, chymotrypsin, elastase, carboxypeptidase A and B
Which of the following best describes the actions of trypsin, chymotrypsin, and elastase?
A. They all hydrolyze interior peptide bonds of proteins and polypeptides.
B. Trypsin activates chymotrypsin and elastase, but only chymotrypsin breaks down proteins.
C. Elastase digests carbohydrates, while trypsin and chymotrypsin hydrolyze lipids.
D. Chymotrypsin and elastase function in the stomach, while trypsin acts in the small intestine.
endo peptidases (hydrolyze interior peptide bonds of proteins and poly peptides) a
what is tha action of carboxy peptidase A and B?
exopeptidases (hydrolyze bonds at the C terminal end)
what do the 4 major proteases leave as end products?
a. mixture of different molecules
b. mixture peptidases
c. mixture of peptides and amino acids
d. mixture of chylomycron and free fatty acids
mixture of peptides and amino acids
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an ezyme that cleabes starches into sugars (maltose, maltotriose, and alpha dextrins)
a. lingual lipase
b. glycogen
c. amylase
d. G6p
amylase
enzyme activated by trypsin that hydrolyzes phospholipids and the end products are free fatty acids and lysophospholipids
a. pro-carboxy peptidase a and b
b. phosholipase A2
c. Lipase
d. cholesterol esterase
phosholipase A2 (inactive form: prephospholipase A2)
enzyme that hydrolyzes triglycerides into free fatty acids and 2-monoglycerides
a. pro-carboxy peptidase a and b
b. phosholipase A2
c. Lipase
d. cholesterol esterase
lipase
enzyme that hydrolyses cholesterol-esters; resulting in free fatty acids and cholesterols
a. pro-carboxy peptidase a and b
b. phosholipase A2
c. Lipase
d. cholesterol esterase
cholestoral esterase
since cck increases gall bladder contractions, what is the benefit of the gall bladder contracting
a. release of hormones
b. release of bile
c. relaxation of shpincter of oddi
d. relaxation of common bile duct
b and c
which of the following is true:
a. secretin stimulates the pancrease to increase bicarbonate secretion via duct cells
b. secretin stimulates liver duct cells to increase bicarbonate secretion
c. secretin stimulates gall bladder contractions
d. secretin inhibits somatostatin
a and b
when is secretin stimulation stopped?
stops when stomach acid is nuetralized (negative feedback system)
what do hepatocytes produce?
bile
steps of bile acid recycling (3)
- bile released from liver/gall bladder into duodenum
- bile acids reabsorbed in the ileum into portal circulation
- bile acids transported back into hepatocytes (liver cells)
Which hormone regulates hepatobiliary secretion during the intestinal phase (respond to these hormones)
A. Gastrin
B. Secretin
C. Cholecystokinin (CCK)
D. Insulin
cck and secretin
