KINE 2031 Lecture Notes - Lecture 15: Nephron, Erythropoietin, Diuretic
2 Jul 2018
School
Department
Course
Professor
Blood Pressure & ECF Volume
-In proximal & loop of Henle, constant Na+ is reabsorbed
-In distal, reabsorption is hormonally controlled
-If Na+ in ECF is high, it holds more water in blood increase blood pressure
-If Na+ in ECF is low, it holds less water in blood decrease blood pressure
-ECF volume is matching change in blood pressure with expansion (increase blood
pressure) or reduction (decrease blood pressure) of plasma volume.
-Long term control of arterial blood pressure depends on Na+ regulating mechanism
Functions of Aldosterone
-Aldosterone increases Na+ reabsorption by distal & collecting tubules
-Aldosterone inserts additional Na+ channels
-Aldosterone increase Na+ reabsorption Na+ osmotically hold more H2O in ECF
increase blood pressure
Summary of Reabsorption & Secretory Processes
-Proximal tubule does most reabsorbing of water & solutes
o2/3 of Na+ is actively reabsorbed, glucose, AA, H2O is osmotically reabsorbed, ½
of urea is passively reabsorbed, K+ reabsorbed
oSecretion of H+ depending on acid-base
-Distal & collecting tubules determines final amounts of H20, Na+, K+ & H+ excreted in
urine
oControl amount of Na+ & H2O reabsorbed; amount of K+ & H+ secreted
oVariable Na+ reabsorption by aldosterone
oVariable H2O reabsorption by vasopressin
oVariable secretion of H+ depending on acid-base
oVariable secretion of K+ by aldosterone
Loop of Henle
-Vertical osmotic gradient exists in medulla. Osmolarity increases within kidney
-Water moves passively out of tubule in descending tubule
-NaCl moves actively out in ascending tubule
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
In proximal & loop of henle, constant na+ is reabsorbed. If na+ in ecf is high, it holds more water in blood increase blood pressure. If na+ in ecf is low, it holds less water in blood decrease blood pressure. Ecf volume is matching change in blood pressure with expansion (increase blood pressure) or reduction (decrease blood pressure) of plasma volume. Long term control of arterial blood pressure depends on na+ regulating mechanism. Aldosterone increases na+ reabsorption by distal & collecting tubules. Aldosterone increase na+ reabsorption na+ osmotically hold more h2o in ecf increase blood pressure. Proximal tubule does most reabsorbing of water & solutes: 2/3 of na+ is actively reabsorbed, glucose, aa, h2o is osmotically reabsorbed, of urea is passively reabsorbed, k+ reabsorbed, secretion of h+ depending on acid-base. Water moves passively out of tubule in descending tubule. Nacl moves actively out in ascending tubule.
