reg renal blood flow and the GFR- Autoreg mechs Flashcards
In the kidney, what does Autoregulation also help with
GFR maintenance
reg of water and solute excretion
What are the two auto reg systems that the kideny uses
myogenic mechanism (pressure sensitive mechanism) tubuloglomerular feedback mech
How does the myogenic work
monitors arterial pressure
uses the intrinsic properties of vascular smooth mus that constrict when stretched. So when art pressure increases the afferent arteriole is stretched causing it to constrict and slow blood flow, then relaxes when art pressure decreases
How does the tubuloglomerular feedback mech work
monitors sodium chloride concentration
the macula densa cells of the juxtaglomerular apparatus sense the levels of sodium chloride and renin releasing cells in the walls of the afferent and efferent arterioles called juxtaglomerular cells. It measures the stretch of the arteriole walls from BP and the concentration of sodium. This information is then used to determine how much renin should be released by juxtaglomerular cells.
What does a decrease in GFR do to sodium chloride
increases reabsorption, causing less to reach the macula densa cells
What does the increased reabsorption of sodium Chlor (or decreased amount hitting the macula densa cells) do
two effects
it decreases resistance to blood flow in the afferent arteriole, causing an increased Glom filtration pressure
it increases the release renin from the juxta cells
What does renin do
acts as an enzyme to the plasma protein angiotensinogen into Angio I, then is Angio I is converted into Angio II in the lungs
What does Angiotensin II do
constricts the efferent arteriole to increase GFR
What is the function of aldosterone
increase sodium and water reabsoprtion
How might lung impairment give you high BP
if you can’t produce the ACE enzyme from the lungs then the RAAS system becomes impaired
What is one way of treating High BP
ACE inhibitors
