Physiology

Question 1

Short term regulation of BP

Answer 1

Baroreceptor reflex

Question 2

Korotkoff sounds

Answer 2

1st is peak systolic pressure

Last sound is heard at minimum diastolic pressure. DIASTOLIC PRESSURE IS RECORDED AS THE FIFTH KOROTKOFF SOUND

Question 3

Right atrium pressure

Answer 3

0

Main driving force for blood is the MAP

Question 4

Normal MAP?

Answer 4

70-105mmHg

Question 5

Minimal MAP needed to perfuse brain, arteries and kidneys?

Answer 5

60mmHg

Question 6

Cardiac output

Answer 6

Volume of blood umped by each ventricle of the heart per minute

Question 7

The major resistance vessels?

Answer 7

Arterioles

Question 8

Where are the baroreceptors?

Answer 8

Aortic arch and carotid sinus
(carotid signals via IXth CN)
(aortic signals via CNX)

Question 9

Important in moment to moment regulation of arterial blood pressure including prevention of postural changes

Answer 9

Baroreceptors reflex

Question 10

What causes postural hypotension?

Answer 10

Results from failure of baroreceptor responses to gravitational shifts in blood, when moving from horizontal to vertical position

Question 11

Why do baroreceptors only respond to acute changes in blood pressure?

Answer 11

Baroreceptors firing decreases if high blood pressure is sustained

Baroreceptors “re-set” - they will fire again only if there is an acute change in MAP above the new higher steady state level

Therefore, the Baroreceptors cannot supply information about prevailing steady state blood pressure

Control of MAP in the longer-term is largely by control of Blood Volume