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8 Posts

01/23/04 - 02:00 PM

A medical student is studying the fluid exchange in skeletal muscle capillaries in a lab animal. He determines that fluid is being forced out of a capillary with a net filtration pressure of 8 mmHg, and he obtains the following lab values:

Capillary hydrostatic pressure = 24 mmHg
Capillary colloid osmotic pressure = 17 mmHg
Interstitial hydrostatic pressure = 7 mmHg

Which of the following is the interstitial osmotic pressure?

A.) -9
B.) -8
C.) -6
D.) 6
E.) 8
F.) 9

* all answers are in mmHg.

meg
Forum Guru

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Posts: 806

01/23/04 - 02:04 PM

01/23/04 - 02:18 PM

i got 9, do you mind showing the calculation? thanks! :oops:

Ouli Maty
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Posts: 275

01/23/04 - 03:53 PM

Filtration= ( cP-iP)-(cO-iO)= 8
where cP=capillary hydrostatic pressure
iP=interstitial hydrostatic pressure
cO=capillary oncotic pressure
iO=interstitial oncotic pressure
Sorry, these are not the classical signs used to describe the Starling equation

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dr.sid
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01/23/04 - 03:53 PM

it is + 8
net filtration pressure=(c.h.p +i.o.p) - (i.h.p +c.o.p)
+8=(24+iop)- (7+17)
this works the interstitial osmotic pressure to + 8
i hope this clears it
and nfp is +8 as fluid is movin out of the capillary ie gettin filtered

01/23/04 - 04:12 PM

thank you! :oops:

mjl1717
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01/23/04 - 04:32 PM

I did exactly what dr. sid did.
(classical q)

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Ouli Maty
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Topics: 33
Posts: 275

01/24/04 - 11:01 PM

Guys, it is still the same equation with the same terms.
Just change the parenthesis around, you end up with the same result.

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