PHSI2006 Study Guide - Final Guide: Plasma Osmolality, Ph, Extracellular Fluid
14 Jan 2019
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Document Summary
Summarise the role of the kidneys in homeostasis of body fluids: regulate volume and composition of the ecf extracellular fluid (and. It does this by: regulating diuresis (water excretion)- controlled by adh which is regulated by plasma osmolality (most sensitive signal) and blood pressure. Composition: mainly concerned with na and k: regulation of natriuresis/ na excretion, 1. This is referred to as pressure naturesis= increase na excretion: another mechanism: colloid osmotic pressure (decrease in this) can also regulate na excretion by increasing gfr, 2. Renin, angiotensin 2 and aldosterone, all regulated by na conc and bp. Decreases na excretion: anp: does the opposite of renin-angio-aldost system. Renal sympathetic nerves: regulate vasoconstriction of afferent and secretion of renin: potassium secretion, (referred to as kaliuresis) is regulated by aldosterone. Acid base balance: it is important for our body to regulate ph= 7. 35-7. 45 (plasma/ extracellular fluid ph). The kidneys excrete h+ protons (they don"t reabsorb protons).
