Water Balance- Note 9 Flashcards
What happens when ADH is released ?
Concentrated urine because water is being reabsorbed by blood stream
What happens when no ADH is released ?
Dilute urine because water Stays in the nephron
ADH and low body water
Decrease body water = increase blood solutes
This means increase in osmotic pressure
Water moves into blood stream causing hypothalamic osmoreceptors to shrink sending signals to the pituitary gland to release ADH
=== concentrated urine thirsty
ADH and high body water
Decrease in bloods osmotic pressure
Water moves back into the body’s cells causing osmoreceptors to swell and deactivate
Less ADH is released and less water is reabsorbed
== urine is less concentrated no thirst
Function of ADH
Regulates osmotic pressure of body fluids by causing kidney to increase water reabsorption
Produced in hypothalamus stored in pituitary gland
ADH and the nephron
- 85% Primary filtrate liquid that makes it go through Bowmans capsule
- Reabsorbed in the proximal convoluted tubule
With ADH in the nephron
Collective duct and distal convoluted tubule become more Permeable to water
Without ADH in the nephron
The remaining water isn’t reabsorbed and is released as urine
Kidneys and blood pressure
Regulate blood pressure banishing blood volume
Increase in fluid loss = decrease in blood pressure
Greater volume = greater pressure
Juxtaglomerular apparatus
BP receptors are in this, detect low BP
Blood pressure low what happens?
Cells release renin, renin coverts angiotensinogen into angiotensin
Angiotensin has two important functions = 1. Hormone that constricts blood vessels
2. Stimulates the release of aldosterone
Aldosterone is hormone released by adrenal gland makes distal convoluted tubule release sodium absorption
Increase NaCl concentration = increase osmotic gradient = increase water reabsorption
