S5L1 - Factors affecting flow through tubes

Question 1

How is blood flow and pressure related?

Answer 1

Blood flow is generated by a pressure gradient. Flow is proportional to the pressure difference between the ends of a vessel.

Question 2

How is blood flow and resistance related?

Answer 2

For a given pressure, the flow is determined by the resistance of the vessel. The resitance of the vessel depends on its radius.

Flow = pressure gradient/resistance

Question 3

Define blood flow and velocity. What is the difference between the two in the circulatory system?

Answer 3

Blood flow remains the same throughout the circulation, but its velocity varies.
Flow = the volume of fluid passing a given point per unit time (ml.s-1)
Velocity = the rate of movement of fluid particles along a vessel (cm.s-1)