Tutorial 3 Cardiovascular disease

Question 1

Explain the meaning of haemodynamics:

Answer 1

• Can be defined as the physical forces that determine the blood flow
• Can be influenced by the heart arte, radius of the blood vessel and the viscosity and volume of the blood
• Can be monitored by the examining BP and HR overtime

Question 2

Explain how BP is regulated:

Answer 2

• BP is dependent on two factors:
  a. amount of blood being pumped by the heart
  b. resistance to flow (the peripheral resistance)

Question 3

Explain the relationship between arterial blood volume and BP:

Answer 3

• Increased stroke volume or HR leads to increased CO, which prompt arterial blood flow and result in increased arterial BP
• Increased blood viscosity or decrease vessel diameter leads to increased peripheral resistance, as a result, impeding the blood velocity while triggering the compensation mechanism of increased VO (induce high BP)

Question 4

Define hypertension and outline how it it managed

Answer 4

• Systolic BP>140; Diastolic BP>90
• Treatment includes:
  a. lifestyle change
  b. drug therapy

Question 5

Describe the role of SNS in the pathogenesis of hypertension:

Answer 5

• increased SNS activity leads to hypertension in 3 MAIN WAYs:
  a. increased HR and peripheral resistance leads to hypertension
  b. insulin resistance leads to endothelial dysfunction, leading to vessel narrowing and vasospasm, inducing hypertension
  c. vascular remodelling and pro-coagulation effect leads to the vessel narrowing causing hypertension

Question 6

Outline the long-term effects of hypertension:

Answer 6

• Myocardial injury
• Coronary artery disease from accelerated atherosclerosis
• Retention of sodium and increased BP due to renin-aldosterone secretion stimulated by the reduced blood flow in the kidneys
• Renal failure
• TIA, stroke, aneurysm from weakened vessel walls and accelerated atherosclerosis
• Retinal vascular sclerosis
• Gangrene in low extremities from accelerated atherosclerosis

Question 7

Define hypotension and outline how it is treated:

Answer 7

• BP below the normal range

- The underlying cause needs to be treated and fluids may be given to increase blood volume and BP

Question 8

Name 3 causes to hypotension:

Answer 8

• orthostatic hypotension
• hypovolemia from:
  a. blood loss
  b. burns
  c. dehydration
  d. fluid shift
  e. diarrhoea
  f. vomiting
• shock

Question 9

Define shock:

Answer 9

• shock is a state in which the supply of blood to the tissue is inadequate to meet the metabolic demand of the body
• regardless of the cause & clinical manifestation; all types of shock result in acute circulation failure, which causes tissue hypoperfusion leading to cellular hypoxia and may causing tissue damage/organ failure
• Shock can result from heart failure, sepsis or an allergic reaction