PHSI 208 Lecture Notes - Lecture 47: Distal Convoluted Tubule, Electrochemical Gradient, Adrenal Cortex
Document Summary
North america diet high in nacl ~9g or 155 milliosmoles of na+ and 155 milliosmoles of. Our plasma na+ concentration is 135-145 milliosmoles/l, na+ is distributed freely b/w plasma and interstitial fluid thus representing our ecf [na+] Normal ecf volume 14l that would be a 10% gain and would cause a large increase in blood pressure. It would increase total body osmolarity from 300-307 mosm: this would draw water from cells disrupting normal function. Anything extra that enters the body is excreted. The kidneys are responsible for most na+ excretion, very little is lost during perspiration and in feces. Although we talk about ingesting and excreting nacl, only na+ absorption is regulated, Cl- tends to follow through the electrochemical gradient set up by na+ movement or co- transported with na+ Regulation of blood na+ levels takes place through a complicated endocrine pathway: the renin-angiotensin-aldosterone system.
