PHGY 214 Lecture Notes - Lecture 5: Sodium-Potassium Alloy, Natriuresis, Headache
12 May 2016
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Document Summary
Topic #5 control of fluid balance: describe the steps of the renin-angiotensin-aldosterone pathway. Promotes arteriolar vasoconstriction: efferent: low aii (to make sure enough fluid goes in the nephron, afferent: high aii (decreases amount that goes into the nephron) Increases na absorption by distal tubule and collecting duct. Does so by promoting the insertion of additional na channels into the luminal membrane (called enac epithelial na channels) as well as additional na/k atpase carriers. Promotes k secretion: describe the similarities and differences in the effects of adh and aldosterone on solute and volume homeostasis. Ecf hypertonicity: water loss without equal electrolyte loss, dehydration. Causes can be insufficient water intake, diabetes insipidus (lack of adh), heavy sweating, diabetes mellitus, vomiting. Water moves from icf to ecf, cell shrinks. Ecf hypotonicity: excess water relative to electrolyte, overhydration. Causes can be rapid water ingestion without electrolyte or excess adh release. Result is that fluid moves from ecf to icf, cell swells.
