Cardiovascular Physiology

Question 1

What is the equation for BP?

Answer 1

BP = CO x SVR

Question 2

What is the equation for CO?

Answer 2

CO = HR x SV

Question 3

What is a normal value for CO?

Answer 3

5L/min

Question 4

What is a normal value for stroke volume?

Answer 4

70ml

Question 5

At what pressure does the mitral valve usually open?

Answer 5

3 mmHg. This is the pressure at which left atrial pressure is greater than left ventricular pressure.

Question 6

Increased vagal nerve activity has a role in restoring/maintaining blood pressure in a hypovolaemic patient T/F

Answer 6

False. Sympathetic (vagus is parasympathetic) nerve activity is increased.

Question 7

Increased firing from baroreceptors has a role in restoring/maintaining blood pressure in a hypovolaemic patient T/F

Answer 7

False. Baroreceptors respond to stretch producing inhibition of output from the vasomotor centre. In hypovolaemia their firing rate is reduced.

Question 8

A rise in angiotensin II concentration has a role in restoring/maintaining blood pressure in a hypovolaemic patient T/F

Answer 8

True. This is part of the hormonal response to hypovolaemia, brought about by renin release from the juxta-glomerular cells.

Question 9

A rise in adrenaline concentration has a role in restoring/maintaining blood pressure in a hypovolaemic patient T/F

Answer 9

True. This is part of the hormonal response to hypovolaemia.

Question 10

Cerebral vasoconstriction has a role in restoring/maintaining blood pressure in a hypovolaemic patient T/F

Answer 10

False. Although generalized vasoconstriction occurs in hypovolaemia, the cerebral vessels are normally spared, thus maintaining perfusion to the brain.