Does ADH increase blood osmolarity?

[EECStoMed]

Does ADH increase plasma osmolarity? For some reason E1001 says that it doesn't, it just says that it increases urine concentration which I agree with.

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[DropkickMurphy]

Does ADH increase plasma osmolarity? For some reason E1001 says that it doesn't, it just says that it increases urine concentration which I agree with.

Reason your way through it....what is the function of ADH? (BTW, you basically just answered your own question)

 

[LadyLightning20]

ADH decreases blood osmolarity. It promotes water retention by making the collecting ducts more permeable to water, so more water is reabsorbed into the blood, which 1) decreases solute concentration in the blood and 2) increases solute concentration in the urine.

 

[EECStoMed]

the funny thing was, both of the statements were as answers and I just happened to pick the "wrong" one. But then I was like WTF, it does increase plasma osmo because it retains water.

 

[AWhitehair]

the funny thing was, both of the statements were as answers and I just happened to pick the "wrong" one. But then I was like WTF, it does increase plasma osmo because it retains water.

Hmm, you sound like you are still a little confused...unless you are just stating what you were thinking *before*? Think of the mnemonic...always digging holes (in the collecting duct) so that water is reabsorbed back into the blood. Therefore, blood osmo decreases.

Sorry if you got it already and I just drove it into the ground!

 

[EECStoMed]

Hmm, you sound like you are still a little confused...unless you are just stating what you were thinking *before*? Think of the mnemonic...always digging holes (in the collecting duct) so that water is reabsorbed back into the blood. Therefore, blood osmo decreases.

Sorry if you got it already and I just drove it into the ground!

Wait, it decreases blood osmolarity? Ok, now I can see that I'm confused. ADH makes the urine more concentrated so then that would put it at a higher osmolarity then? Higher osmolarity means more solute per/L correct? So because the blood would have more water, it would be be at a lower osmolarity? Am I making sense here? What about Aldosterone? Does it increae or decrease blood osmolaritY?

 

[w00tz]

Wait, it decreases blood osmolarity? Ok, now I can see that I'm confused. ADH makes the urine more concentrated so then that would put it at a higher osmolarity then? Higher osmolarity means more solute per/L correct? So because the blood would have more water, it would be be at a lower osmolarity? Am I making sense here? What about Aldosterone? Does it increae or decrease blood osmolaritY?

ADH increase water reabsorption into plasma that would otherwise end up in urine. Take away water from urine and it becomes more concentrated. Add water to the blood and the molarity goes down/becomes less concentrated. Aldosterone, while it increases Na+ reuptake, I think water immediately follows, so there is no change in osmolarity.

 

[EECStoMed]

Really, no plasma osmolarity change?

ADH increase water reabsorption into plasma that would otherwise end up in urine. Take away water from urine and it becomes more concentrated. Add water to the blood and the molarity goes down/becomes less concentrated. Aldosterone, while it increases Na+ reuptake, I think water immediately follows, so there is no change in osmolarity.

 

[evoviiigsr]

Think of ADH as anti dehydration hormone.... allows water to be reabsorbed into bloodstream, preventing dehydration

 

[evoviiigsr]

ADH increase water reabsorption into plasma that would otherwise end up in urine. Take away water from urine and it becomes more concentrated. Add water to the blood and the molarity goes down/becomes less concentrated. Aldosterone, while it increases Na+ reuptake, I think water immediately follows, so there is no change in osmolarity.

I think that with aldosterone there is a change in osmolarity. It works in the collecting duct by triggering synthesis of Na ion channels, but there is no way for water to move out of the collecting duct without water channels (which ADH puts on the membrane)