Which of the following changes would produce the greatest change in total peripheral resistance?
a. 10% change in vessel length
b. 10% change in blood viscosity
c. 10% change in vessel diameter
d. 10% change in cardiac output

The correct answer is: c) 10% change in vessel diameter

Explanation:

Total peripheral resistance is one of the main factors that affects blood pressure, and refers to the resistance that blood cells and plasma encounter when they contact blood vessel walls. The other three factors that affect blood pressure are vessel elasticity, blood volume and cardiac output.

Total peripheral resistance has three main sources: blood vessel diameter, blood viscosity and total vessel length.

Vessel diameter affects peripheral resistance in the following way: as the diameter gets smaller, a greater proportion of the fluid enters in contact with the wall, resistance increases and pressure rises. In contrast, as the diameter gets larger, resistance decreases, resulting in less pressure.