PHYSL402 Lecture Notes - Lecture 21: Nephron, Adrenomedullin, Baroreceptor
7 Nov 2016
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Greater bv translate into increased bp; picked up by baroreceptors (also have baroreceptors in kidneys) increased perfusion p in kidneys. Control of gfr (filtered na+ load: renal perfusion p, symp nerve activity, renin angiotensin system. Ultimately, reduction in plasma v increased activity of renal sympa nerves, which constric afferent and efferent (afferent, preferentially) decreased gfr and filtered na load (conserves na) Na+ excreted = (na+ filtered) (na+ reabsorbed) Steroid hormone produced in zona glomerulosa of adrenal cortex. Quantity of na+ reabsorption dependent on aldosterone is ~ 2% of total filtered load (30g nacl) (right): highlighted variable reabsorption; low when low need and vice versa. Cli(cid:374)i(cid:272)al (cid:272)ases of aldostero(cid:374)e release: ie (cid:374)o aldostero(cid:374)e (addiso(cid:374)"s disease lose na) Co(cid:374)(cid:374)"s disease = adre(cid:374)al tu(cid:373)or = o(cid:448)erprodu(cid:272)tio(cid:374) of aldostero(cid:374)e hypertension. Acts on principal cells in distal tubule (same as vasopressin) Requires > 45 min to manifest effects (protein synthesis takes time) Na+/k+ exchange urine na+ decreased, k+ increased.
