Blood Volume and Blood Pressure

[ahs4n]

Why does the passive reabsorbing of water via ADH cause increase of blood pressure? I understand volume increases due to water being reabsorbed but isn’t pressure and volume inversely related?

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[loveoforganic]

Directly related. If you blow more air in a balloon, it's not going to shrink.

 

[ahs4n]

Yeah but if you blow more air into the balloon, the volume increases. Doesn't the pressure decrease? Pressure = force divided by area. Area increases so pressure decreases. Boyle's law also states that pressure and volume are inversely related.

Is something in my assumptions wrong? Kind of confused...help!

 

[loveoforganic]

You're assuming that the moles of air in the balloon remain constant. That's not true. You are blowing additional air into the balloon

 

[werd]

first of all, you can't use the ideal gas equation to discuss the behavior of liquids. secondly, if you shove more of something into the same space the pressure goes up no matter what phase you're talking about. thirdly, ADH acts directly on vascular receptors to cause vasoconstriction, which is the main way it increases blood pressure. werd.

 

[ahs4n]

Appreciate your explanation, that set me straight.