young_doc
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What effect will the removal of one kidney have on the Total Peripheral Resistance?
According to Kaplan, it will decrease TPR.
But if you remove an organ from a parallel system of resistance, it should increase TRP....:
Ex. 1/R = 1/2 + 1/2
In this example, R = 1
If we remove one of the organs, then it will be 1/R = 1/2, and hence R will equal 2. (i.e. increases TPR).
Anyone know why it's supposed to decrease TPR?
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| study_ing
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if ure sure abt the answer i can invent an expalnation
one kidney removesd means less renin etc secreted so less vasoconstriction may be...
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| study_ing
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but i gotta admit the first thing i tot of was what u did..kindly give ur reference from kaplan
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| vallia
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you're calculation are correct, removing one organ from a parralel resistance circuit will increase TPR.
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| young_doc
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thanks for the input guys. it was actually Qbank...or 'maybe' BSS. Cuz all i'm doing now is those 2. So it had to be one of those 2.
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| MRMAVERICK
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| gaby
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kaplan : TPR after removing a kidgney increase.
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| new_n_lost
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Now Guys when i saw this post trust me i forgot wht wud happen the reference i could think of this. i hope this clears out any confusions this an Excerpt from Guyton n Hall Physiology Textbook:-
One-Kidney" Goldblatt Hypertension. When one kidney is removed and a constrictor is placed on the renal artery of the remaining kidney, the immediate effect is greatly reduced pressure in the renal artery beyond the constrictor. Then, within seconds or minutes, the systemic arterial pressure begins to rise and continues to rise for several days. The pressure usually rises rapidly for the first hour or so, and this is followed by a slower additional rise during the next several days. When the systemic arterial pressure reaches its new stable pressure level, the renal arterial pressure will have returned almost all the way back to normal. The hypertension produced in this way is called "one-kidney" Goldblatt hypertension in honor of Dr. Goldblatt, who first studied the important quantitative features of hypertension caused by renal artery constriction. The early rise in arterial pressure in Goldblatt hypertension is caused by the renin-angiotensin vasoconstrictor mechanism. That is, because of poor blood flow through the kidney after acute constriction of the renal artery, large quantities of renin are secreted by the kidney, and this causes increased angiotensin II and aldosterone in the blood. The angiotensin in turn raises the arterial pressure acutely. The secretion of renin rises to a peak in an hour or so but returns nearly to normal in 5 to 7 days because the renal arterial pressure by that time has also risen back to normal, so that the kidney is no longer ischemic. The second rise in arterial pressure is caused by retention of salt and water by the constricted kidney (that is also stimulated by angiotensin II and aldosterone). In 5 to 7 days, the body fluid volume will have increased enough to raise the arterial pressure to its new sustained level. The quantitative value of this sustained pressure level is determined by the degree of constriction of the renal artery. That is, the aortic pressure must rise high enough so that renal arterial pressure distal to the constrictor is enough to cause normal urine output.
"Two-Kidney" Goldblatt Hypertension. Hypertension also can result when the artery to only one kidney is constricted while the artery to the other kidney is normal. This hypertension results from the following mechanism: The constricted kidney secretes renin and also retains salt and water because of decreased renal arterial pressure in this kidney. Then the "normal" opposite kidney retains salt and water because of the renin produced by the ischemic kidney. This renin causes formation of angiotension II and aldosterone both of which circulate to the opposite kidney and cause it also to retain salt and water. Thus, both kidneys, but for different reasons, become salt and water retainers. Consequently, hypertension develops.
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| giovanni83
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Goldblatt did experiments on hypertension on kidneys, but the original question in this thread is effect of kydney on pressure, there is not starting hypertensin as in Goldblatt ones...
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| verapamil
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the flow through each individual nephron is in series. maybe that's why tpr decreases if you take out 1 kidney. that's just my opinion.
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| hanwin
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What is the final answer?
For me, I would go for Increased TPR.
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