Renal Physiology/pathophysiology

*Stenosis will result in hypoperfusion of kidney on the same side>Activarion of RAAS, so Renin will be increased in the vein of affected kidney, while it will be Decreased in the vein of unaffected kidney(Because the opposite kidney is perfused just fine and also JGA on that kidney will sense all that extra salt/water that was absorbed because the affected kidney "thought" body was hypovolemic, so basically in unaffected kidney Renin secretion will be decreased)...HOWEVER they asked you contribution of UNAFFECTED kidney to hypertension and best choice would be Aldosterone-induced sodium and water retention, because Aldosterone secretion from Zona glomerulosa which was induced by Ag2 will Make BOTH kidneys retain Na and water and excrete potassium....

*RHABDOMYOLYSIS>Release of Myoglobin>KIdney damage.

*60% of total mass is TBW and so 60 L here(NWM is whatever is left=40%)...Note that ICF is 40% of TOTAL BODY MASS(NOT TBW)and ECF is 20% of TOTAL Body mass...So here ICF would be 40L, ECF would be 20, you can think about them also in terms of TBW and basically ECF makes up 1/3 of it(1/3 of 60 here would be again 20L, which is 20 % of 100) and ICF makes up 2/3 of TBW(so here 2/3 of 60=40, which is 40% of 100)In summary don't mix up 20 and 40% which refer to TOTAL BODY MASS(here 100kg) vs 1/3 and 2/3 which refer to TBW(60% of Total body mass)*Now if you know ECF then you can find out Volume of plasma and interstitial fluid which together make up this compartment...Now key here too is knowing %, basically Plasma is Only 25%(1/4) of ECF thus here it is 1/4 x 20=5 , while Interstitial fluid is whatever is left from ECF, in our case 15(which obv. is 3/4 or 75% of ECF...)Hematocrit would be around 45 because he is male(Hematocrit is around 45 % of TBW in males and it is around 40% of TBW in females.<because females have more fat and thus less fluid if you know what i mean :)

*Well not directly but yea, all you got to do is to measure ECF volume by Inulin/Mannitol and then around 25 % of that would be approximate value of Plasma volume....But If they ask you BEST/Most accurate measure for PLALSMA Volume ,then pick Radiolabeling albumin....on the contrary if you knew plasma volume(by radiolabeling albumin), then you could approximate ECF by multiplying the Plasma volume by 4, but then again more accurate measure of ECF would need Mannitol/Innulin..

***MAJOR CATion in ICF is Kvs***MAJOR CATion in ECF is Na....Major ANIONS in ECF are CL and HCO3...vsMajor ANIONS in ICF:ORGNANIC phosphates,PROTEINS.Osmolarity is same in BOTH compartments and it is around 290(between 285-295) and it is No BS, because that means that there is NO net movement of fluid between these 2 compartments at rest....

*FIRST of all get your units.....1g=1000 mg... <So your plasma concentraiton of albumin is 25 mg after injection of 1000 mg...So plasma volume=1000/25=40dL(mg's canceled out), they will likely give you answers in Liters so 40 dL=4 LITERS.you could get approximate answer just by knowing body weight(ECF is 20 % of 70, then all you do is calculate 25% of that value, so you get around 3,5 L that way)

*YES they are freely filtered, but Most of the listed substances are REABSORBED, because we need them while garbage(Like creatinine) that was also filtered with them isn't reabsorbed....*The reason those good guys are filtered is that they are around the size of the "Garbage" that should be filtered, so it's kinda necessary evil, in other words these substances along the "Garbage" have to be smaller then 50-60nm, because anything more than that would be blocked from being filtered by SLIT DIAPRHRAGMS of PDOCYTES(Size barrier), while anything that is even larger like BLOOD CELLS/ particles >100 nm moleculres, would be blocked even before that by FENESTRATED capillay epithelium itself...(fenestrations aren't just large enough to let them pass)

*3 layers-BASEMENT membrane(with Type 4 collagen and HEPARAN SULFATE), Podocyte foot processes of epithelial layer and Even FENESTRATED capillary Endothelium, all make up CHARGE barrier, because they contain NEGATIVELY charged GLYCOPROTEINS which prevent entry of NEGATIVELY charged molecules like Albumin...(Remember - and - repel vs - and + attract each other), so with Nephrotic syndrome when we loose Charge barrier we get Albuminuria/Hypoproteinemia>Decreased oncotic pressure>Edema...

*Well it makes sense that increased urine flow would be manifestation of increased clearance, it also makes sense that if you have higher clearance you would excrete substance more into urine, so urine concentration would increase while Plasma concentration would decrease...hence the formula we haveCx=U(urine concentration)timesV(Urine flow rate)/P(plasma concentration)

*GFR is approximately equal To Inulin clearance(and that's how they give you info about GFR), because while FREELY Filtered, inulin is NOT reabsorbed or secreted....so When GFR=Clearance=There is no reabsorbtion or secretion(Like inulin), thus obviously when Clearance of substance<Clearance of Inulin(represents GFR) we could say that substance is "NET reabsorbed" while if clearance of substance>clearance of inulin then we could say that it is "NET secreted"...Normal GFR is around 100 and they can make you approximate GFR just by giving you Creatinine values, HOWEVER they could compare creatinine and inulin clearance to check if you know why Creatinine slightly overestimates GFR, and you should know that small amount of creatinine is secreted by renal tubules thus clearance of Creatinine is slightly more than clearance of Inulin and thus it slightly overestimates the GFR.

*BOTH increase GFR because they basically pull the fluid towards Bowman capsulealso remember

GFR=50x100/60=83.3ml/HrBUT they asked mL/Min, so you got to divide this by 60.(60 mins=1hr)so answer: 1,4 mL/min....

*The one that is slightly MORE, because remember that PAH clearance is ALMOST 100% not quiet 100%, so it slightly UNDERestimates EFFECTIVE renal plasma flow..Note that Secretion of PAH happens in Proximal tubule and needs ENERGY dependent Organic Acid transporter....

Well RBF=RPF/Plasma...Plasma=RBF/RPF....Plasma also =1-HctSo Hct=1-Plasma.....

*NO, because dilation of Afferent(Arriving)arterioles will increase RPF and GFR in the same proportion so their ratio(GFR/RPF) will stay the same...*NSAIDs block the normal vasodilatory effect of prostaglandins on afferent arterioles and thus can lead to Kidney Ischemia...vsAg2 preferentially CONSTRICTS Efferent(Exiting) arterioles, and so blood can't get out from glomeruli as much and so more is filtered out, so GFR Increases, because there is constriction at the outflow, not as much Plasma can get inside so RPF decreases, so overall GFR/RPF ratio(Fitration fraction) will Increase...<ACE inhibitors block Ag2 formation and thus prevent Efferent arteriolal constriction and thus they prevent hyperfiltration damage by deceasing GFR,Increasing RPF and Decreasing FF...