Exploring Poiseuille's Law: Pressure, Flow, and Resistance in Blood Vessels

In summary, the conversation discusses the concepts of hydrostatic pressure and flow in relation to Poiseuille's Law. The participants question the effects of decreasing the diameter of a tube on flow, as well as the relationship between flow and heart rate. They also consider the role of atmospheric pressure and vessel dilation in maintaining equilibrium and how that affects hydrostatic pressure. The main takeaway is that a better understanding of pressure is needed before these questions can be answered.
  • #1
sameeralord
662
3
Ok first of all before I get to this I have one question,

What does loss of hydrosatic pressure due to resistance mean in this equation. What happens to the molecules when they lose hydrostatic pressure, do they stop moving and accumulate?

Poiseuille's Law says that if you decrease the diameter there is less flow? My question is the dimater is decreased the speed of the particles increase? Can't this counteract the less volume entering the tube and create the same flow?

If there is low flow. Let's say in artery why does increasing heart rate increase flow?
Is the reason behind this?

A----------------------------------B ( o mh/hg)
(Heart increase pressure at point A to 200 mg/hg)

Does this create a higher pressure difference and a higher flow? If hydrostatic pressure is acting perpendicular to the surface how can it push molecules in a horizontal direction?

Also when you just start to pump blood to an artery and point A has flow pumped and B still hasn't? Wouldn't B be compressed due to atmospheric pressure outside?

Also when a blood vessel is dilated?

-----------------------------<(o mg/hg)
A-100 mg/hg

If the point of flow is to maintain 100 mg/hg everywhere around the tube, why does hydrostatic pressure inside a dilated tube increase? I mean when it reached 100 mg/hg doesn't the flow stop? How is equilibrum reached here?
 
Physics news on Phys.org
  • #2
The OP needs to gain a better fundamental understanding of the concept of pressure before his questions regarding Poiseuille flow can be answered.
 

1. What is Poiseuille's Law?

Poiseuille's Law is a mathematical formula that describes the relationship between the pressure, flow rate, and resistance in a cylindrical tube, such as a blood vessel.

2. How does Poiseuille's Law relate to blood flow in the body?

Poiseuille's Law is used to understand and predict the flow of blood through the blood vessels in the body. The law states that the flow rate of blood is directly proportional to the pressure gradient and the fourth power of the radius of the blood vessel, and inversely proportional to the length and viscosity of the blood vessel.

3. What factors affect resistance in blood vessels?

Resistance in blood vessels is affected by several factors, including the diameter of the blood vessel, the length of the blood vessel, and the viscosity of the blood. Other factors such as blood pressure, blood flow, and the elasticity of the blood vessel walls can also impact resistance.

4. How is Poiseuille's Law used in medical research?

Poiseuille's Law is commonly used in medical research to understand and predict the flow of blood in the body. It is also used to study the effects of various conditions and diseases on blood flow, such as atherosclerosis or hypertension. This law is also applied in the development of medical devices, such as stents and catheters, that are used to treat cardiovascular diseases.

5. Is Poiseuille's Law applicable to all blood vessels in the body?

Poiseuille's Law is most applicable to long, narrow blood vessels, such as arterioles and capillaries, where the flow of blood is laminar. However, it can also be used to estimate blood flow in larger vessels, such as arteries and veins, as long as certain assumptions are made about the blood flow. These assumptions include the blood being incompressible, the blood vessel being straight, and the blood flow being steady and non-pulsatile.

Similar threads

Replies
18
Views
1K
  • Introductory Physics Homework Help
Replies
16
Views
1K
  • General Engineering
Replies
3
Views
2K
  • Biology and Medical
Replies
10
Views
2K
Replies
4
Views
2K
  • Biology and Medical
Replies
4
Views
2K
  • Biology and Medical
Replies
3
Views
1K
  • Introductory Physics Homework Help
Replies
6
Views
2K
Replies
1
Views
1K
Replies
1
Views
808
Back
Top