Pressure difference to maintain blood flow

In summary, if a non-smoker's blood viscosity is 2.5x10-3 Pa's, normal blood flow requires a pressure difference of 8.0 mm of Hg between the two ends of an artery. If a smoker's blood viscosity increases to 2.7x10-3 Pa's, the arterial diameter constricts to 90% of its normal value. To maintain the same blood flow, a pressure difference of 4.0x10-3 mmHg would be needed.
  • #1
twiztdlogik
12
0
hey guys.. i need a bit of help on this question...

For a non-smoker, with blood viscosity of 2.5x10-3Pa's, normal blood flow requires a pressure difference of 8.0 mm of Hg between the two ends of an artery. If this person were to smoke regularly, his blood viscosity would increase to 2.7x10-3 Pa's, and the arterial diameter would constrict to 90% of its normal value. What pressure difference would be needed to maintain the same blood flow?

any help here would be greatly appreciated!

cheers :smile:
KC
 
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  • #2
twiztdlogik said:
For a non-smoker, with blood viscosity of 2.5x10-3Pa's, normal blood flow requires a pressure difference of 8.0 mm of Hg between the two ends of an artery. If this person were to smoke regularly, his blood viscosity would increase to 2.7x10-3 Pa's, and the arterial diameter would constrict to 90% of its normal value. What pressure difference would be needed to maintain the same blood flow?

Hi KC! :smile:

Show us what you've tried, and where you're stuck, and then we'll know how to help! :smile:
 
  • #3
ok, this is what i had so far... not sure if i am on the right track or not though...

non smoker:2.5 x 10^-3 Pa.s
smoker: 2.7 x 10^-3 Pa.s

density of blood @ 1 atm: 1060 kg/m3

normal blood flow: [tex]\Delta[/tex] 8.0 mmHg

pressure difference:
smoker - nonsmoker = 2 x 10^-4

pressure difference: ________________________________

that's where i am not sure about what to do.

i tried: 8.0 mmHg / 2 x 10^-4 = 40,000 mmHg or 4.0 x 10^-3...
but i know that that's not the answer coz i haven't taken into account for the 10% constriction of the artery.:bugeye:

any clues or nudges in the right direction would be GREAT! :biggrin:
 
  • #4
twiztdlogik said:
ok, this is what i had so far... not sure if i am on the right track or not though...

non smoker:2.5 x 10^-3 Pa.s
smoker: 2.7 x 10^-3 Pa.s

density of blood @ 1 atm: 1060 kg/m3

normal blood flow: [tex]\Delta[/tex] 8.0 mmHg

pressure difference:
smoker - nonsmoker = 2 x 10^-4

pressure difference: ________________________________

that's where i am not sure about what to do.

i tried: 8.0 mmHg / 2 x 10^-4 = 40,000 mmHg or 4.0 x 10^-3...
but i know that that's not the answer coz i haven't taken into account for the 10% constriction of the artery.:bugeye:

any clues or nudges in the right direction would be GREAT! :biggrin:

Hi twiztdlogik! :smile:

I have to confess I only know about non-viscous flow. :redface:

But this looks to me like a dimensions question … y'know, of the "if three men take two days to paint a cube, how long do seven men take to paint a cube with twice the radius and with brushes half as small and paint twice as thin" sort. :wink:

So what equation do you know relating pressure to viscosity and diameter and flow? :smile:
 
  • #5
erm.. are you thinking of the poiseuilles equation...?
i think that would work if i can transpose it to get the right formula for this situation

thanks any ways!
 

FAQ: Pressure difference to maintain blood flow

What is pressure difference in the context of maintaining blood flow?

Pressure difference refers to the difference in pressure between two points in a system. In the context of maintaining blood flow, it refers to the difference in pressure between the arteries (high pressure) and veins (low pressure) that allows blood to flow through the body.

Why is pressure difference important for maintaining blood flow?

Pressure difference is important for maintaining blood flow because it creates a driving force that pushes blood through the circulatory system. Without this pressure difference, blood flow would slow down or stop, leading to inadequate delivery of oxygen and nutrients to the body's tissues.

How is pressure difference regulated in the body?

The body regulates pressure difference through a variety of mechanisms. These include vasoconstriction (narrowing of blood vessels) and vasodilation (widening of blood vessels), as well as changes in heart rate and stroke volume. The body also uses hormones and the autonomic nervous system to control blood pressure and maintain proper pressure difference for blood flow.

What happens if there is an imbalance in pressure difference?

If there is an imbalance in pressure difference, it can lead to problems with blood flow and circulation. For example, if the pressure difference is too high, it can strain the heart and blood vessels, increasing the risk of heart disease and stroke. On the other hand, if the pressure difference is too low, it can result in poor circulation, leading to conditions like hypotension and shock.

How does exercise affect pressure difference and blood flow?

Exercise can have a significant impact on pressure difference and blood flow. During exercise, the body's demand for oxygen and nutrients increases, leading to an increase in pressure difference and blood flow. This is achieved through a combination of increased heart rate, vasodilation of blood vessels in the muscles, and the release of hormones that regulate blood pressure. Regular exercise can also help maintain healthy blood pressure and improve overall cardiovascular health.

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