Integrative cardiovascular response

Question 1

What are ‘baroreceptors’?

Answer 1

Receptors which detect blood pressure on a beat to beat basis. Their firing frequency changes with changes in blood pressure.

Question 2

What happens with a FALL in blood pressure?

Answer 2

Causes cartoid and aortic baroreceptors to detect hypotensive stimulus leading to decrease in afferent baroreceptor nerve firing. Reduction in neural input to brainstem causes a decrease in parasympathetic nerve activity to heart and increase sympathetic outflow to the heart and vasculature.

Converse occurs with increased blood pressure.

Question 3

What happens with a FALL in blood pressure?

Answer 3

Causes cartoid and aortic baroreceptors to detect hypotensive stimulus leading to decrease in afferent baroreceptor nerve firing. Reduction in neural input to brainstem causes a decrease in parasympathetic nerve activity to heart and increase sympathetic outflow to the heart and vasculature.

Converse occurs with increased blood pressure.

Question 4

What is the equation for mean systemic arterial pressure (MAP)?

Answer 4

MAP = Cardiac output x Total peripheral resistance (TPR)

Question 5

During exercise, what 3 places does blood flow increase to?

Answer 5

• Skeletal Muscle:
  o Supply of O2 and removal of metabolic waste
• Skin:
  o Dissipation of heat
• Heart:
  o O2 supply (cardiac muscles extracts almost all O2 from blood even at rest)