CSB325H1 Lecture Notes - Lecture 4: Aldosterone, Juxtaglomerular Cell, Vasopressin
29 Nov 2014
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Document Summary
Cellular dehydration = extracellular osmolality. > intracellular osmolality: osmolality is the amount of dissolved ions, e. g. , fluid leaves cell = triggers cellular dehydration. Decreased extracellular volume = volume changes without osmolality changes: e. g. , loss of blood volume = drop in blood pressure. Cascade is triggered by renin rate limiting step. Angiotensin- ii binds to cortex of adrenal gland: receptor 1 and 2 have opposite effects, angiotensin- ii receptors. At1 receptor, which is inhibited by arbs: vasoconstriction. Stimulation of cell growth: at2 receptor. Angiotensin- ii regulates star protein, which is the rate limiting enzyme in steroid hormone synthesis. Secretes aldosterone(steroid hormone: released from adrenal cortex in response from angiotensin- ii, which contain at1 receptors. Zona fasciculate cortisol, dhea. Zona reticularis dhea, androstenedione. Na+ resorption in distal tubules = na+ K+ excretion = k: renin production, maintain vasopressin responsiveness by regulating adenylyl cyclase. Negative feedback: macula densa cells controls juxtaglomerular cells: aldosterone decreases renin secretion.
