Blood Pressure

Question 1

What is the flow of oxygenated blood to deoxygenated blood back to the heart?

Answer 1

Oxygenated blood goes from the heart through the arteries->arterioles then to the capillaries for gaseous exchange. Deoxygenated blood then flows through the venues-> veins and to the heart.

Question 2

What is the structure and function of arteries, arterioles, capillaries, veins and venues?

Answer 2

Arteries: large, thick, elastic
Arterioles: regulate perfusion, pre capillary sphincters (closed= increased resistance
Capillaries: thin, diffusion, gaseous exchange
Veins/venules: have valves to prevent back flow

Question 3

What innervates blood vessels?

Answer 3

All except capillaries innervated by SNS
Norepinephrine (SNS transmitter) smooths muscle in walls
SNS maintains vasomotor tone: blood vessels normal= constricted half of max
Increase SNS= further constriction
Inhibition of normal tone=dilation

Question 4

What is vasoconstriction and vasodilation?

Answer 4

Vasoconstriction: increased contraction-> increased resistance and decreased flow

Vasodilation: decreased contraction-> decreased resistance and increased flow

Question 5

What is the difference between diastolic and systolic blood pressure?

Answer 5

Systolic BP: pressure exerted on arterial walls during ventricular systole (contraction)

Diastolic BP: pressure exerted on arterial walls during ventricular diastole (relaxation)

Question 6

What happens when blood decreases?

Answer 6

increase in heart rate to maintain BP levels

Question 7

What is cardiac output?

Answer 7

Amount of blood pumped out by each ventricles in one minute (cardiac output= stroke volume x heart rate)

Question 8

What is the Baroreceptor reflex?

Answer 8

Baroreceptors: feedback for short-term regulation of BP and peripheral resistance
Baroreceptors-> vasomotor centre-> SNS-> HR & peripheral resistance

Question 9

What is a direct method for measuring blood pressure?

Answer 9

Invasive catheterisation: most accurate
Catheter inserted direct into artery, pressure transducer monitors changes in BP, continuous measurement, used in trauma/critical care

Question 10

What is a indirect method for measuring blood pressure?

Answer 10

auscultatory:
Inflatable cuff, Hg manometer and stethoscope
Stethoscope over brachial artery, inflate cuff to occlude artery (no sound), deflate while listening for Korotkoff sounds
First sound= systolic pressure
Last sound= diastolic pressure

Sounds are hard to hear and requires training

Question 11

How does blood pressure relate to stress?

Answer 11

Generally increased in stress-> increase in BP
effects greater SBP than DBP

Study: effects of stress depend on ability to influence outcome active/passive coping