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Glomerular Filtration Rate (view source)
Revision as of 18:03, 9 December 2010
, 18:03, 9 December 2010no edit summary
Despite the efforts of the autoregulatory system an increase in blood pressure still leads to an increased secretion of salt and water. This is because even a small percentage change in GFR leads to large percentage change in the excretion of salt and water. This excretion is however far less drastic than would be the case without autoregulation and actually helps to restore pressure to normal. This increase in urinary output as a result of an increase in arterial blood pressure is termed [[Kidney - Blood Pressure - Anatomy & Physiology#Pressure Diuresis|pressure diuresis]].
Despite the efforts of the autoregulatory system an increase in blood pressure still leads to an increased secretion of salt and water. This is because even a small percentage change in GFR leads to large percentage change in the excretion of salt and water. This excretion is however far less drastic than would be the case without autoregulation and actually helps to restore pressure to normal. This increase in urinary output as a result of an increase in arterial blood pressure is termed [[Kidney - Blood Pressure - Anatomy & Physiology#Pressure Diuresis|pressure diuresis]].
====[[Renin Angiotensin Aldosterone System|Angiotensin 2]]====
====[[Renin Angiotensin Aldosterone System|Angiotensin 2]]====
* Increased conservation of water and sodium
* Increased conservation of water and sodium
====[[The Effects of Nitrous Oxide and Prostaglandins on GFR - Anatomy & Physiology|Nitrous Oxide and Prostaglandins]]====
====Nitrous Oxide and Prostaglandins====
Nitrous Oxide and Prostaglandins have an impact on arteriolar resistance. Their role in the regulation of renal blood flow and filtration is however uncertain.
=====Nitrous Oxide=====
* Mediates dilation in the cortical circulation
=====Prostaglandins=====
* Mediates dilation in medullary circulation (cortical in extremes)
* PGE2 is involved in the regulation of the reabsorption of sodium
* Prostacyclin increases the secretion of potasium by stimulating renin secretion thus activating the [[Renin Angiotensin Aldosterone System| Renin-Angiotensin-Aldosterone System]] and as a result increasing the amount of [[Aldosterone]] secreted.
* '''Prostacyclin increases renal blood flow and gfr when circulating volume is decreased.''' This results in increased tubular flow and increased potasium secretion
* In healthy/hydrated individuals these compounds do not play a significant role in sodium/water homeostasis
=====Effects of Blocking Nitric Oxide or Prostaglandins=====
* Loss of medullary circulation - reduced ability to concentrate water
* Loss of medullary flow - reduces the ability to preserve sodium balance and maintain normal blood pressure
* Loss of either may result in ischaemic damage
[[Category:Urinary System - Anatomy & Physiology]]
[[Category:Urinary System - Anatomy & Physiology]]