BIOL373 Lecture Notes - Lecture 4: Ionic Strength, Proximal Tubule, Sodium-Potassium Alloy
16 Feb 2017
School
Department
Course
Professor
Document Summary
Low blood pressure/volume response: baroreceptors in aorta and carotid artery sense low volume/pressure, and trigger homeostatic re exes to increase blood pressure. Fast response: quick adjustment of cardiovascular system (increase cardiac output and vasoconstriction) Long term response: increase water consumption (thirst) increase reabsorption of water in the kidneys. High blood pressure/volume response: new problem evolutionarily, caused by stress and obesity, cardiovascular system decreases cardiac output and vasodilates, kidneys excrete salts and water. Water balance: ideally should be balanced, inputs include drinks/food (variable) and metabolism (non variable), outputs include water loss at skin/lungs (non variable), urine and feces (variable) Produce dilute urine: reabsorb solutes without letting water follow, epithelial cells need to be impermeable to water in order to keep water in the tubules (low expression of aquaporins) Product concentrated urine: reabsorb water but leave solutes in the tubule, tubular epithelial cells need to be highly permeable to water (high expression of aquaporins)
