2 Haemodynamics

Question 1

What is blood serum?

Answer 1

Blood plasma without clotting factors

Question 2

Name a condition which affects whole blood viscosity

Answer 2

• Polycythaemia
• Thrombocythaemia
• Leukaemia

Question 3

What does meauring plasma viscosity give us an indication of?

Answer 3

Inflammation

Question 4

What’s the difference between Laminar and Turbulent flow?

Answer 4

Laminar: smooth, maintaining energy

Turbulent: disorganised, energy= lost

(stenosed arteries and ventricles)

Question 5

What units are used for ‘flow’?

Answer 5

Volume transferred per unit time

L/min

Question 6

What is conductance?

Answer 6

Measure of ease of flow

Question 7

What is Darcy’s law?

Answer 7

If resistance increases- pressure is changed to maintain flow

Question 8

Which blood vessels contribute most to the overall peripheral resistance in the body?

Answer 8

Smallest arteries and arterioles

Question 9

Is resistance lower in the pulmonary or systemic circulatory systems?

Answer 9

Pulmonary (shorter and wider vessels)

Question 10

Fill in the missing gaps in the following equations:

Answer 10

Question 11

What is the ‘pulse’ we feel?

Answer 11

Shock wave before blood arrives

Question 12

What 2 factors is pulse pressure governed by?

Answer 12

• Vol of ejected blood
• Compliance of arterial system

Question 13

What condition may cause a ‘bounding pulse’?

Answer 13

• Heart block (bradycardia)
• Vasodilation (hot bath/pregnancy)
• Elite athletes
• CO2 retention

Question 14

What are the 3 factors which affect resistance in blood vessels?

Answer 14

1. Diameter (quantitively most important)
2. Vessel length
3. Viscosity

Question 15

What are Korotkoff sounds?

Answer 15

Sounds due to noise of turbulent flow

Question 16

You are asked to measure a patients blood pressure. It is important to find the right cuff size. If the cuff is too big how might this affect the measurement?

Answer 16

Underestimate pressure