Arterial Pressure Regulation

Question 1

What are non-invasive blood pressure recordings?

Answer 1

inflatable finger cuff

• retains a record of inflation pressure and inverts it to give recording of ABP
• hand positioned at heart level

Question 2

Why would ABP be lower if hand is held at head level?

Answer 2

blood pushes down on the site youre measuring from because of gravity

this is why you keep hand at heart level - to avoid errors in mercury difference

Question 3

Why are phasic changes more obvious in healthy individuals who exercise regularly?

Answer 3

• HR goes down if you exercise regularly, vagal tone is gained and resting sympathetic activity decreases
• ventricular muscles become stronger = increased CO

Question 4

Explain the changes when theres rapid breathing.

Answer 4

eg stress and anxiety

lung stretch receptors and more central respiratory neural activity

effects: tachycardia, dizzy as not enough oxygen reaching brain - more CO2 out of lungs to blood - cerebral arteries constrict - less oxygen to brain

Question 5

Which pathiological conditions would you expect to carry a high risk from the CV effects of coughing?

Answer 5

cough = high ABP

those with coronary heart disease = more work for heart muscle

aortic anuerysm can burst = death due to haemorrhage

Question 6

When standing, why is there a small increase in ABP and bradycardia followed by a fall in ABP and higher HR?

Answer 6

when first standing:

• more venous return to heart = higher CO = higher BP - baroreceptors detect this and decrease HR

After:

• venous pooling in legs = less venous return to heart = less blood to pump out = less CO = less BP - detected by baroreceptor reflex

Question 7

If ABP falls when standing, but HR is fine what does this mean?

Answer 7

baroreceptor reflex is fine

theres sympathetic dysfunction - only the vagal nerve works

Question 8

How does crouching, putting one leg up, crossing legs and bending over raise ABP?

Answer 8

crouching: contraction of leg muscles and less gravity = venous pooling stopped = more venous return to the heart

putting one leg up: muscle contraction

crossing legs: muscle contraction

bending over: less height difference = diff in Mercury = less venous pooling