Vasopressin

This forum made possible through the generous support of SDN members, donors, and sponsors. Thank you.
L

Lubdub222

Full Member
10+ Year Member
15+ Year Member
Joined
Jun 26, 2008
Messages
11
Reaction score
0
Members don't see this ad.
The plasma osmolality decreases after infusion of:

a. aldosterone
b. ADH
c. angiotensin II
d. parathyroid hormone
e. saline solution

Answer is B--> ADH, why?
 
Sort by date Sort by votes
The osmolality of plasma is closely regulated by anti-diuretic hormone (ADH). In response to even small increases in plasma osmolality (usually rises in plasma sodium), ADH release from the pituitary is increased causing water resorption in the distal tubules and collecting ducts of the kidney and correction of the increased osmolality. The opposite happens in response to a low plasma osmolality with decreased ADH secretion and water loss through the kidneys. Note that ADH is also secreted in response to hypovolaemia and this stimulus will over-ride any response to serum osmolality.
 
Upvote 0 Downvote
but dont aldosterone and angiotensin II do the same thing?

IndianGraduate said:
The osmolality of plasma is closely regulated by anti-diuretic hormone (ADH). In response to even small increases in plasma osmolality (usually rises in plasma sodium), ADH release from the pituitary is increased causing water resorption in the distal tubules and collecting ducts of the kidney and correction of the increased osmolality. The opposite happens in response to a low plasma osmolality with decreased ADH secretion and water loss through the kidneys. Note that ADH is also secreted in response to hypovolaemia and this stimulus will over-ride any response to serum osmolality.
Click to expand...
 
Upvote 0 Downvote
dreamdental said:
except PTH all options decrease osmolality.correct me
Click to expand...

Aldosterone increases total salt load, which brings water with it osmotically. It has no effect on osmolality. Saline is isomolal and has no effect on osmalality, which is why they use it for basically everything in a medical setting. ADH is the only thing that increases the absorption of free water.
 
Upvote 0 Downvote
armorshell said:
Aldosterone increases total salt load, which brings water with it osmotically. It has no effect on osmolality. Saline is isomolal and has no effect on osmalality, which is why they use it for basically everything in a medical setting. ADH is the only thing that increases the absorption of free water.
Click to expand...
osmolality decrease by increase in plasma volume.please correct me
 
Upvote 0 Downvote
It makes much much more sense now! Thank you.

armorshell said:
Aldosterone increases total salt load, which brings water with it osmotically. It has no effect on osmolality. Saline is isomolal and has no effect on osmalality, which is why they use it for basically everything in a medical setting. ADH is the only thing that increases the absorption of free water.
Click to expand...
 
Upvote 0 Downvote
You must log in or register to reply here.
Top