Lecture 26 - Vascular Function

Question 1

Pressure drop?

Answer 1

across small arteries and arterioles

Question 2

Area velocity relationship?

Answer 2

inverse proportionality

Question 3

Largest surface rea?

Answer 3

capillaries

Question 4

Determinants of blood viscosity?

Answer 4

temperature, haematocrit (RBC portion), shear rate (sludging of RBC at v low velocity), vessel diameter

Question 5

Assumptions of Poisseuille’s equation?

Answer 5

steady laminar flow, newtonian flow, rigid straight tube

Question 6

Shear stress?

Answer 6

as flow increases, stress on endothelium increases, causing NO release and vasodilation - potential risk of damage

Question 7

Reynolds number increases if?

Answer 7

increased diameter, increased flow or decreased resistance

Question 8

Bernoulli’s Principle?

Answer 8

total energy of laminar flow is constant and euals sum of: pressure energy, potential energy and kinetic energy (some energy loss due to heat)

Question 9

Transmural pressure?

Answer 9

pressure inside - pressure outside

Question 10

Aneurysm?

Answer 10

thinning of vessel wall, radius increase, wall tension increase, viscous circle