Stimulus for renin angiotensin system?

[sameeralord]

Hello everyone,

I have to write a simple essay about this,I know what to write but I'm stuck with the stimulus so can't start the essay. My textbook is so vague. I want to know the stimulus in a haemorrhage.

1. Is it the decrease in renal perfusion pressure detected by afferent arteriole that secretes renin.
2. Or decrease in sodium chloride deteced by the macula densa that stimulates it.

Thanks

 

[bobze]

Hello everyone,

I have to write a simple essay about this,I know what to write but I'm stuck with the stimulus so can't start the essay. My textbook is so vague. I want to know the stimulus in a haemorrhage.

1. Is it the decrease in renal perfusion pressure detected by afferent arteriole that secretes renin.
2. Or decrease in sodium chloride deteced by the macula densa that stimulates it.

Thanks

If you have a decrease in renal perfusion, what does the macula densa "see". Does it see more or less sodium? That is how the kidney regulates RAAS.

You should note though, that the RAAS system is complex and requires lots of feed back modifiers. Atrial stretch receptors (barroreceptors) can also alter circulating renin levels.

 

[mtc1973]

have a look at beta 1 receptors in the autonomics section of any pharm text - and tie that in with the baroreceptor response bobz mentioned