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Biology AS Questions

I stumped on some questions, once again we havn't even been taught it and I have no text book:

What is the link between insufficient protein in the diet and the accumulation of tissue fluid?

And a little maths question that I can't remember how to do:

During exercise the rate of blood folw to the heart increases from 270cm3 per minute to 750cm3 per minute. Calculate the percentage increase in rate of blood flow to heart muscle during exercise.
Reply 1
TwistedVidual
I stumped on some questions, once again we havn't even been taught it and I have no text book:

What is the link between insufficient protein in the diet and the accumulation of tissue fluid?

And a little maths question that I can't remember how to do:

During exercise the rate of blood folw to the heart increases from 270cm3 per minute to 750cm3 per minute. Calculate the percentage increase in rate of blood flow to heart muscle during exercise.



Maths question: 750 - 270 = 480
480/250 x 100 = 192% increase

Tissue fluid: proteins can't pass through the capillaries, so they stay in the blood. This creates osmotic pressure causing water to leave the tissue fluid and enter the blood. So if you don't have enough protein in your blood, you don't have a force driving water out of the tissue fluid and so the fluid builds up...
Reply 2
Proteins in the blood (albumin...I think) are to big to fit through fenestrations, so stay in the blood, (arterial end)

at the venule end, the osmotic gradient causes the reabsoption of water.

Hope that makes sense, I'm a little tired right now....

ETA: MadNatSci got there before me, oh well, I'm sure her explanation makes more sense :smile:
Reply 3
Hey, both explanations sound abit dodge to me. If ur doin AQA, this is the mark scheme answer cause that question came up on the jan 2004 paper:



"The tissues of people who are starving often swell because of the accumulation of tissue fluid. Explain what causes this accumulation of tissue fluid." (2 marks)


Ans: Starvation means a lower intake of essential amino acids into the diet hence less protein is synthesised. Tissue fluid is not reabsorbed therefore due to no or less water potential gradient as less protein is present in the capillaries to cause reabsorption of water as well as small molecules. So tissue fluid builds up.
Reply 4
That means the same thing...!?!
Reply 5
Sorry if it does. Just thought ud like the AQA quick and dirty version.
Reply 6
MadNatSci
Maths question: 750 - 270 = 480
480/250 x 100 = 192% increase


I did that the first time, but I thought the answer was wrong, ah well.

Thanks to you all for helping though :biggrin:
Reply 7
umm the maths one:

is it this???..

750-270=480
(480/270) x 100 =178%increase

it's divide by 270 rather than 250??
Reply 8
hihihihi
umm the maths one:

is it this???..

750-270=480
(480/270) x 100 =178%increase

it's divide by 270 rather than 250??



Whoops, sorry, yes! But I'm sure he knew what I meant... :redface: