Changes

==Effects of Angiotensin 2 on GFR==

==Effects of Angiotensin 2 on GFR==

If blood pressure drops then [[The Formation of the Filtrate by the Glomerular Apparatus- Anatomy & Physiology#Glomerular Filtration Rate|glomerular filtration rate (GFR)]] also drops due to a reduced blood flow through the kidneys.  Therefore it is important to prevent this.  If contraction of the efferent arteriole occurs then the pressure difference between the afferent and efferent arterioles increases creating a greater filtration pressure.  This effect is mediated by Angiotensin 2 and means that when blood pressure falls there is minimum alteration of GFR.  Blood flow which is already reduced due to the reduced pressure will then be further reduced by the increase in resistance.  This increased renal resistance to blood flow and the maintained GFR has many advantageous effects.   

If blood pressure drops then [[The Formation of the Filtrate by the Glomerular Apparatus- Anatomy & Physiology#Glomerular Filtration Rate|glomerular filtration rate (GFR)]] also drops due to a reduced blood flow through the kidneys.  Therefore it is important to prevent this.  If contraction of the efferent arteriole occurs then the pressure difference between the afferent and efferent arterioles increases creating a greater filtration pressure.  This effect is mediated by Angiotensin II and means that when blood pressure falls there is minimum alteration of GFR.  Blood flow which is already reduced due to the reduced pressure will then be further reduced by the increase in resistance.  This increased renal resistance to blood flow and the maintained GFR has many advantageous effects.   

===Advantages of Constriction of the Efferent Arteriole===

===Advantages of Constriction of the Efferent Arteriole===