Help With Excretory System!

[TheGuy2000]

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Hey all, before this board gets inundated with score reports, thought I'd try to ask a quick question. As far as the kidney is concerned how much should we know? The descending limb of the loop of henle is permeable to water, ascending not, but after that it gets kind of confusing. ADH increases water reabsorption, I remeber from the endocrine, but I'm just stuck on the in between parts! Can anyone help?

 

[junebuguf]

Hey all, before this board gets inundated with score reports, thought I'd try to ask a quick question. As far as the kidney is concerned how much should we know? The descending limb of the loop of henle is permeable to water, ascending not, but after that it gets kind of confusing. ADH increases water reabsorption, I remeber from the endocrine, but I'm just stuck on the in between parts! Can anyone help?

You actually need to know excretory mechanisms in-depth. Not because any question will test the info directly, but because you will very likely be presented with info regarding a drug or a genetic defect (leading to a misformed product) that causes some effect A. Effect A then leads to an increase in the concentration of some hormone which affects some part of the renal system causing effect B. Identify effect B. I would strongly recommend that you memorize EVERY hormone and all the details of the renal and digestive systems (all the enzymes, what is digested/absorbed where, et).

I had a question on my form in April that specifcally dealt with the absorption of fats, which are taken into lacteals and processed by the lympathic system. Such is the depth required by the MCAT.

 

[rimanek]

Based on the practice tests (and one real test) that I've taken, I'd suggest you know much more about the physiology than that descending loop is permeable to water and ascending is not.

For example, you should know the function of the glomerulus (e.g., filtrate produced but cells cannot pass), that most organic compounds get transported out in the proximal convoluted tubule, why does it makes sense that the descening loop is permeable to water but ascending is not, what the difference in mechanism of function is between ADH and aldosterone, etc.

I hope this helps.