Step I Renal Hypoxia

[AlbertConstable]

When the kidney loses blood and/or oxygen supply, which is the most vulnerable area? Medulla? Cortex? Does it change depending on what is causing the insult?

Couldn't find a good source to clear that up for me. Thanks in advance.

 

[blz]

When the kidney loses blood and/or oxygen supply, which is the most vulnerable area? Medulla? Cortex? Does it change depending on what is causing the insult?

Couldn't find a good source to clear that up for me. Thanks in advance.

cortex gets 90% of the arterial supply so the medulla is relatively hypoxic as it is.

 

[staphaureus]

changes = reversible coagulative necrosis if reperfusion is in time to preserve the basement membrane.

 

[SOUNDMAN]

cortex gets 90% of the arterial supply so the medulla is relatively hypoxic as it is.

This is why I think it's even MORE susceptible to hypoxia. Just like the liver is more susceptible to hypoxia closer to the central vein verses near the incoming portal vein. (Zone 3 versus Zone 1).

In RR pathology - Ischemic ATN causes damage to the tubule cells in ATN.

I would think one would see more damage in the medulla than the cortex, because it is already hypoxic and even a small insult to vascular supply would cause greater damage here vs. the cortex.

Just some thoughts...

 

[predodoc]

I thought it was the medulla also, but somewhere I remember reading the Proximal tubule is prone damage because lots of O2 and energy is needed for all the active reabsorbtion that is going on there. Anyone know for sure?

 

[TX_Longhorn]

predoc is right. the straight portion of the prox tubule has a lot of Na-K atpase pumps because of all the reabsorption and secretion it is involved in.

also the thick ascending limb of the loop of henle is very susseptible to ischemia, according to great goljan (i guess thats bc of its location in the medulla)

 

[blz]

dude, you guys misread what i wrote - the medulla IS more susceptible to hypoxia (because it only gets 10% of the bloodsupply). what's the confusion here?

 

[blz]

I thought it was the medulla also, but somewhere I remember reading the Proximal tubule is prone damage because lots of O2 and energy is needed for all the active reabsorbtion that is going on there. Anyone know for sure?

you do realize the straight portion of the PT is in the medulla right?

 

[predodoc]

The PT and distal Tub. are in the cortex. The loop of henle is in the medulla. The Pt gets the blood and O2 before the loop does but because like 65% of all reabsorbtion in the kidney is in the PT then its more prone to damage. But, the medulla(loop of henle) is also prone since its blood supply is less, so I dont know which one is the MOST prone?

 

[predodoc]

you do realize the straight portion of the PT is in the medulla right?

If you meant that PT= peritubular capillary then yes its in the medulla

 

[blz]

If you meant that PT= peritubular capillary then yes its in the medulla

the straight portion of it (pars recta proximal tubule) extends into the outer portion of the medulla.

 

[Doc 2b]

 

[SOUNDMAN]

so we are going with medulla aren't we? 😀

Blz, your answer seemed vague to me when you tried to answer the question initially, that's where the confusion was I guess on my part.

 

[joe6102]

the straight portion of it (pars recta proximal tubule) extends into the outer portion of the medulla.

For Step 1 purposes, I think we can assume the entire proximal tubule is in the cortex. And according to Goljan, the cortical part is the part most susceptible to hypoxia.

RR path, page 4:
"The straight portion of the proximal tubule in the cortex is most susceptible to hypoxia."

 

[blz]

For Step 1 purposes, I think we can assume the entire proximal tubule is in the cortex. And according to Goljan, the cortical part is the part most susceptible to hypoxia.

RR path, page 4:
"The straight portion of the proximal tubule in the cortex is most susceptible to hypoxia."

nope - listen to his lecture on renal - he says the straight portion is in the medulla. i dont' really care what goljan says anyways - it is, what it is. i still think the medulla is most susceptible to ischemic injury - which is what the OP was asking.