The relationship of blood flow (Q), resistance (R), and pressure (P) in a vessel can be expressed by which equation?

The relationship of blood flow (Q), resistance (R), and pressure (P) in a vessel can be expressed by which equation?

A. Q = P/R.

B. Q = R/P.

C. Q = PQ.

D. P = Q / R

Answer:

A. Q = P/R.

Explanation:

Resistance is the force that counteracts the blood flow and slows down the speed of the blood flow. It occurs due to friction between blood and the walls of blood vessels. Resistance is regulated by the size of the blood vessels, length of the blood vessels and viscosity. Blood always flows from the region of the higher blood pressure towards the lower one. Therefore, blood flow is directly proportional to pressure and is indirectly proportional to the resistance.

So, Q = P/R

Option A, Q = P/R

Explanation:

Complete question is

The relationship of blood flow (Q), resistance (R), and pressure (P) in a vessel can be expressed by which equation?

A. Q = P/R.

B. Q = R/P.

C. Q = PQ.

D. P = Q / R

Solution

As we know that

Resistance in blood flow is directly proportional to the blood pressure and inversely proportional to the blood flow. This can be represented as

R ∝ P

R ∝ 1/Q

On combining the above two equations, we will get the following

R ∝ P/Q

R = KP/Q

Where K is the proportionality constant.

Resistance in blood flow arises when the blood vessels constricts or there is some blockage in the blood vessel or wall of the blood vessel creates higher frictional force.

This resistance increases the pressure but the flow reduces.

Hence, option A is correct