BIO310H5 Lecture Notes - Lecture 13: Macula Densa, Angiotensin-Converting Enzyme, Angiotensin
Document Summary
Monitor [na+] at the filtrate (not blood); na+ is already reabsorbed here. Reflex arc thru sympathetic ns will respond by either vasoconstricting bvs, or leaving the vessels as is depending on the situation. Can be secreted directly (baroreceptors they detect high bp at major bvs) is low bp is detected. Sympathetic ns plays a dual role either by directly releasing renin from juxtaglomerular apparatus, or by vasoconstriction (as seen from above under macula densa) Angiotensin i gets converted to angiotensin ii. Angiotensin i + angiotensin converting enzyme form angiotensin ii. Angiotensin ii will either cause vasoconstriction or will reach adrenal cortex and activate aldosterone, which acts on dct to increase na+ reabsorption and production of adh: angiotensin ii functions: -stimulate release of aldosterone (see slide) Note: angiotensin ii will also act on parasympathetic ns and thirst center. Note: all this renin stuff occurs in response to low bp less and less water loss will help preserve cardiac output.
