Blood Flow: Laminar vs Turbulent || Reynold's Number

Video Summary:
Blood flow is a quantity of blood that passes a given point in the circulation in unit time. Laminar blood flow is seen when blood flows at a steady rate through a long and smooth blood vessel. Here velocity increases as we go from the vessel wall to the center. Turbulent flow occurs in case of very high blood flow, obstruction in a vessel, sharp turn and rough surface. Reynolds number is the measure of the tendency for turbulence to occur. Large diameter of larger vessels and high velocity in high cardiac output conditions tend to cause turbulence whereas the viscosity of the blood tends to prevent it. Murmurs produced by turbulence are important in measuring blood pressure and in the diagnosis of some conditions like vessel stenosis, shunts and cardiac valvular lesions.

🎞 More videos on the Physiology of CVS

● Follow me at:

Chapters
00:00 Blood Flow
00:59 Laminar Blood Flow
01:54 Turbulent Blood Flow
02:27 Reynold's Number
04:31 Summary

Dr. Vipul Navadiya

DISCLAIMER: This video is for education purposes only. Although every effort is made to ensure the accuracy of the material, viewers should refer to the appropriate regulatory body/authorized websites, guidelines, and other suitable sources of information as deemed relevant and applicable. In view of the possibility of human error or changes in medical science, any person or organization involved in the preparation of this work accepts no responsibility for any errors or omissions, or results obtained from the use of information in this video.

[tufaidulislamtohin]

Too good, my every confusion is cleared

[edhelhernandez]

Your videos have been getting me through PA school thanks Dr. Navadiya

[alirezasouri]

thank you so much for your clear and good information.

[SajitaKu]

Sir plz make a video on 2nd gas effect. Ur videos r very useful!
Keep it up sir!

[ahmedkudo-dxyt]

When the diameter decrease the reynold's number decrease also despite the equation.
Since the velocity is also related to diameter through the equation v=Q/πd2

[worldaround]

In laminar flow, the pressure is lowest and the velocity is highest at the center of the pipe, while the velocity is lowest and the pressure is highest at the periphery. Why is this the case?

I will try to give an intuitive answer since I don't have a mathematical one. If you find any mistakes, please point them out.

Due to friction with the wall, the velocity is lowest at the periphery.

Due to friction with the walls in the periphery, you would need a higher pressure to counteract the friction related to wall. This is similar to how electricity works: higher resistance means the voltage difference across the resistor is also higher.

How does higher resistance or friction lead to the formation of higher voltage or greater pressure? Let us consider a bunch of electrons flowing through a circuit. When they encounter a resistor, initially only some electrons will be able to cross it; the rest will accumulate at the starting point of the resistor. This accumulation of electrons creates a potential difference, pushing the remaining electrons to move across the resistor. Once the flow of electrons due to this push becomes equal to the flow of electrons elsewhere in the circuit, further accumulation stops, and this is how voltage is formed.

A similar phenomenon occurs with water: the accumulation of water due to friction creates pressure, pushing other water molecules. The flow of electrons in conductors is not entirely similar to the flow of liquids. For example, water molecules attract each other, while electrons repel each other. Due to this repulsion, electrons mostly travel along the periphery of wires, a phenomenon known as the skin effect.