Blood Pressure

Question 1

How is MAP estimated

usually roughly 100mmHg

Answer 1

Area under curve of pressure (look at cardiac cycle diagram)

The diastolic pressure + 1/3 pulse pressure

pulse pressure is systolic minus diastolic pressure

Question 2

What determines MABP?

Answer 2

Cardiac output x TPR

Question 3

What are the short term regulators of MABP?

Answer 3

Nervous activity mainly so effects of vasoconstriction and vasodilation, as well as effects on the heart so inotropy aletring SV and HR being altered

Question 4

What regulates MABP in the long term

Answer 4

Fluid control by the kidneys, affecting CO mainly, not TPR

Question 5

What influences aortic pulse pressure

Answer 5

Systolic: Stroke volume; aortic compliance
Diastolic: aortic compliance; run off from aorta ( TPR and heart rate)

Question 6

How does compliance of blood vessels (namely the aorta) alter with age

Answer 6

It decreases, so as the vessel becomes more filled with collagen (more stiff), for a given volume the change of pressure is larger. Thus pulse pressure will increase (increase in systolic pressure)

Question 7

How does TPR alter diastolic pressure

Answer 7

If you increase TPR, there is a less rapid run off, thus increasing diastolic pressure. vice versa. This will decrease the pulse pressure

Increased heart rate means higher diastolic pressure- less time for run off