Question

What will happen if the diameter of artery is reduced?

• A. Blood Pressure will fall
• B. Blood Pressure will increase
• C. Blood pressure will remain same
• D. Blood will coagulate

Hint:

In circulatory problems, remember that any change in the diameter of blood vessels will affect the resistance and subsequently the blood pressure.

Answer 1

The Correct Option is B

When the diameter of an artery is reduced, the resistance to the flow of blood increases, causing the blood pressure to rise.
Thus, the correct answer is Blood Pressure will increase.

Answer 2

The diameter of an artery plays a crucial role in regulating blood flow and blood pressure in the circulatory system.

Effect of Diameter Reduction:
When the diameter of an artery decreases, it causes the blood vessels to become narrower.
This narrowing increases the resistance to blood flow because the same volume of blood must pass through a smaller opening.

Relationship with Blood Pressure:
According to the principle of fluid dynamics (Poiseuille’s law), resistance to flow is inversely proportional to the fourth power of the radius of the blood vessel.
Even a small decrease in artery diameter significantly increases resistance.
To maintain adequate blood flow, the heart must pump with greater force, leading to an increase in blood pressure.

Physiological Implications:
Increased blood pressure due to narrowed arteries is a common feature in conditions such as atherosclerosis.
This can strain the heart and increase the risk of cardiovascular diseases like hypertension, heart attack, and stroke.

Summary:
- Reduced artery diameter → Increased resistance to blood flow.
- Increased resistance → Blood pressure rises.
- Higher blood pressure puts extra strain on the cardiovascular system.