cardiovascular control mechanisms

Question 1

calculating resistance in a fluid circuit (Darcy’s law)

Answer 1

pressure difference = volumetric flow x resistance

Question 2

calculating mean arterial blood pressure using cardiac output

Answer 2

blood pressure (MAP) = cardiac output (CO) x total peripheral resistance (TPR)

Question 3

when calculating resistance and blood pressure approximation, what are 3 assumptions

Answer 3

steady flow, rigid vessels, right atrial pressure is negligible

Question 4

approx cardiac output at rest

Answer 4

5 L/min

Question 5

approx cardiac output at exercise

Answer 5

20 L/min (decrease flow to gut, increase flow to heart and muscle)

Question 6

calculating cardiac output

Answer 6

heart rate x stroke volume

Question 7

calculating stroke volume

Answer 7

end-diastolic volume - end-systolic volume

Question 8

approx stroke volume at rest

Answer 8

70ml

Question 9

calculating pulse pressure (force required for heart to contract)

Answer 9

systolic blood pressure - diastolic blood pressure

Question 10

approx pulse pressure

Answer 10

40mmHg

Question 11

calculating mean arterial pressure

Answer 11

diastolic pressure + 1/3 pulse pressure (due to corresponding times spent in these pressures)

Question 12

approx mean arterial pressure

Answer 12

93mmHg

Question 13

define cardiac output

Answer 13

volume of blood leaving either side of the heart per minute