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Old 07-22-2012
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Help Resistance, pressure... flow

Hello guys... quick Q here... suddenly, I got stucked with the concept of

"Resistance is directly proportional to viscosity and inversely proportional to the radius to the 4th power."

I've learned the definition.. I just forgot how to apply it... S.O.S. my exam is next week. Any help will be more than welcome
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Old 07-22-2012
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[QUOTE=Dr. Mexito;134666]Hello guys... quick Q here... suddenly, I got stucked with the concept of

"Resistance is directly proportional to viscosity and inversely proportional to the radius to the 4th power."

I've learned the definition.. I just forgot how to apply it... S.O.S. my exam is next week. Any help will be more than welcome[/

Check FA 2011 pg 256
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Old 07-22-2012
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Originally Posted by Dr. Mexito View Post
Hello guys... quick Q here... suddenly, I got stucked with the concept of

"Resistance is directly proportional to viscosity and inversely proportional to the radius to the 4th power."
polycythemia - increased resistance
anemia - decreased resistance

vasoconstriction - incresed resistance
vasodilation - decreased resistance
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Old 07-23-2012
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Originally Posted by Casandra View Post
polycythemia - increased resistance
anemia - decreased resistance

vasoconstriction - incresed resistance
vasodilation - decreased resistance
I was thinking about that part were they mention... if you reduce the R by half... what next????

I get so confused... I've memorized the definition, but haven't been able to put it on practice.
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Old 07-23-2012
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Originally Posted by Dr. Mexito View Post
I was thinking about that part were they mention... if you reduce the R by half... what next????

I get so confused... I've memorized the definition, but haven't been able to put it on practice.

If you reduce the R by half - vasoconstriction (and all the other parameters, eg. viscocity, remain constant) the resistance increases 8 times (1/2xR to the 4th power + inverse relation).

Let me know if this is what you were asking about
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Old 07-24-2012
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Originally Posted by Casandra View Post
If you reduce the R by half - vasoconstriction (and all the other parameters, eg. viscocity, remain constant) the resistance increases 8 times (1/2xR to the 4th power + inverse relation).

Let me know if this is what you were asking about
If we reduce radius by half shouldn't the resistance increases by 16 folds i.e(1/2*1/2*1/2*1/2)=1/16 and as everyone has mentioned resistance and radius have inverse relation ship so resistance increases by 16 folds

please correct me if I am wrong???
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Old 07-24-2012
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Originally Posted by offpiste View Post
If we reduce radius by half shouldn't the resistance increases by 16 folds i.e(1/2*1/2*1/2*1/2)=1/16 and as everyone has mentioned resistance and radius have inverse relation ship so resistance increases by 16 folds

please correct me if I am wrong???
yup, you are right - my mistake!
It should be 16 (2 to power 4)

Thanks for correcting me offpiste

And as I wrote before the resistance will increase
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Old 08-24-2012
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Quote:
Originally Posted by offpiste View Post
If we reduce radius by half shouldn't the resistance increases by 16 folds i.e(1/2*1/2*1/2*1/2)=1/16 and as everyone has mentioned resistance and radius have inverse relation ship so resistance increases by 16 folds

please correct me if I am wrong???
1) 2* radius = 1/16 R ~16* FLOW (Q)
2) 1/2 radius + 16* R ~1/16* Q

acording to above given data:

1) when 2 times radius increases,resistance will decreases about 16 times, and flow will increases about 16 times
2)when 1/2 of radius decrease ,16times resistance will increases and flow will decreases about 16 times
am i right??

please help me i always confuse here ,
after completing physio subject when i move to next subject this chapter easily wash out from mine brain then again i put mine ful eforts here to undrstand this one chapter,from next month mine triad wil start, am so tense about few physio chapters they easily wash out from mine brain, what i do i have no time to again go through dvds

Last edited by riya_rai84; 08-24-2012 at 12:53 AM.
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