Question

Characteristic features of different blood vessels in the body are shown. What does P,Q and R represent?

• A. P: Total area Q: Velocity R:Blood pressure
• B. P: Blood pressure Q: Velocity R: Total area
• C. P: Velocity Q: Total area R: Blood pressure
• D. P: Total area Q: Blood Pressure R: Velocity

Answer 1

Answer: (B)

P: Blood pressure Q: Velocity R: Total area

The total cross- sectional area of the body's capillary beds is far greater than any other type of vessel. The diameter of an individual capillary is significantly smaller than the diameter of an arteriole.

The blood pressure drops as blood travels from arteries to arterioles, capillaries, venules and veins and encounters greater resistance.

The velocity of blood flow decreases dramatically as the blood moves from arteries to arterioles to capillaries. This slow flow rate allows more time for exchange processes to occur.

So, the correct answer is 'P: Blood pressure Q: Velocity R: Total area'.