Blood Pressure

[Medgen]

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Why does the reabsorption of Na or Cl cause blood pressure to increase? Wouldn't it increase the osmotic pressure and thus decrease the hydrostatic pressure? I am trying to figure out why aldosterone causes the blood pressure to increase.

 

[justhanging]

Cause it indirectly causes reabsorption of water as well.

 

[PiBond]

Why does the reabsorption of Na or Cl cause blood pressure to increase? Wouldn't it increase the osmotic pressure and thus decrease the hydrostatic pressure? I am trying to figure out why aldosterone causes the blood pressure to increase.

Aldosterone causes the reabsorption of Na+ in the collecting duct. This will cause an increase in blood osmolarity which is a trigger for the release of ADH from the posterior pituitary. ADH inserts aquaporins and causes water to be reabsorbed which increases blood volume. The increased blood volume results in increased blood pressure.

So in truth, Aldosterone and ADH work as a team to increase BP.

 

[ThirdEye]

Reabsorbtion is also independent of hormones in the proximal conv. tubule. So with or without hormones, reabsorbtion of ions is occuring in the PCT, and water follows with it.