Why do people with high blood pressure avoid salty foods?

[SephirothXR]

What is the sequence of events that causes increased blood pressure? You consume salt, aldosterone is released, Na+ is absorbed (from the distal convoluted tube), and now that there is increased osmolarity (in the plasma? What's this region called where the salt goes), there is increased uptake of water via osmosis, and thus your blood pressure is higher. Did I interpret this right (it was part of a practice passage I took but I want to understand the overall process).

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[whiteshadodw]

What is the sequence of events that causes increased blood pressure? You consume salt, aldosterone is released, Na+ is absorbed (from the distal convoluted tube), and now that there is increased osmolarity (in the plasma? What's this region called where the salt goes), there is increased uptake of water via osmosis, and thus your blood pressure is higher. Did I interpret this right (it was part of a practice passage I took but I want to understand the overall process).

salt in and of itself doesn't stimulate aldosterone release. usually stress and dehydration stimulate the anterior pituitary to release ACTH (produced in the hypothalamus). ACTH stimulates the adrenal cortex to release cortisol and aldosterone. that doesn't have much to do with this though.

however, you are correct that increased blood osmolarity (ion absorption through small intestine) results in a higher concentration of ions in prefiltrate (in the kidney). the kidney is incredibly efficient at reabsorbing salt and water, but when it absorbs salt it absorbs even more water. increase in water absorption leads to increase in blood volume, more blood volume = more pumping needed, more pumping requires higher blood pressure.

 

[SephirothXR]

Thanks, that clears up a lot of it. So when you consume high salty foods, why do you feel dehydrated?

 

[Ferocity]

salt in and of itself doesn't stimulate aldosterone release. usually stress and dehydration stimulate the anterior pituitary to release ACTH (produced in the hypothalamus). ACTH stimulates the adrenal cortex to release cortisol and aldosterone. that doesn't have much to do with this though.

however, you are correct that increased blood osmolarity (ion absorption through small intestine) results in a higher concentration of ions in prefiltrate (in the kidney). the kidney is incredibly efficient at reabsorbing salt and water, but when it absorbs salt it absorbs even more water. increase in water absorption leads to increase in blood volume, more blood volume = more pumping needed, more pumping requires higher blood pressure.

ACTH is both produced and secreted from the anterior pituitary. For the MCAT the only two hormones which are produced in the hypothalamus are secreted by the posterior pituitary (Oxytocin and ADH).

 

[whiteshadodw]

ACTH is both produced and secreted from the anterior pituitary. For the MCAT the only two hormones which are produced in the hypothalamus are secreted by the posterior pituitary (Oxytocin and ADH).

crap you're right. i had this mixed up.

it might be worthwhile to know GnRH, TRH, GHRH, CRH since they control release of some hormones from the AP.