CSB325H1 Lecture Notes - Lecture 5: Zona Glomerulosa, Macula Densa, Adenylyl Cyclase
18 Dec 2013
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Document Summary
Osmoregulation involves two main processes: maintenance of a constant volume of internal fluids during changing ion concentrations, maintenance of a constant ratio of ions during changing body fluid levels. Osmoregulation at the cellular level involves: permeability of membranes, active transport across membranes, passive movement of materials across membranes, diameter of blood vessels and filtration rate in kidneys. 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. Low plasma na+ low na+ in distal tubules macula densa juxtaglomerular cells renin. At1 receptor, which is inhibited by arbs. Angiotensin-ii regulates star protein, which is the rate limiting enzyme in steroid hormone synthesis. Released from adrenal cortex, which contain at1 receptors: zona glomerulosa aldosterone, zona fasciculate cortisol, dhea, zona reticularis dhea, androstenedione.
