Physiology

Question 1

diastole

Answer 1

ventricular relaxation and blood filling

Question 2

stroke volume

Answer 2

volume of blood ejected from each ventricle during systole

Question 3

isovolumetric

Answer 3

contraction but no change in volume

Question 4

4 stages of cardiac cycle?

Answer 4

1. Isovolumetric ventricular contraction
2. ventricular ejection/emptying
3. isovolumetric ventricular relaxation
4. ventricular filling

Question 5

Mean arterial pressure definition and equation

Answer 5

average arterial BP over entire cardiac cycle

MAP = CO x TPR

Question 6

Heart sounds

Answer 6

‘LUBB DUBB”
1st - closure of AV valve
2nd - closure of SL valve

Question 7

Atrial kick

Answer 7

At end of diastole. Elevated atrial pressure forces small amount of blood into ventricle

Question 8

When are peak ventricular and aortic pressure reached?

Answer 8

before the end of ventricular ejection

Question 9

Does the ventricle empty fully?

Answer 9

No

Stroke volume = EDV - ESV

Question 10

Cardiac output equation

Answer 10

CO = SV x HR

cardiac muscle SA node

Question 11

The nervous system increases the stroke volume by increasing which 3 things?

Answer 11

End-diastolic volume
Plasma epinephrine
Activity of sympathetic nerves to the hear

Question 12

HR is increased by what?

Answer 12

increase in plasma epinephrine
stimulation of sympathetic nerves to the heart
inhibition of PS nerves to the heart

Question 13

How does sympathetic stimulation increase HR?

Answer 13

increases slope of pacemaker potential by:

• increasing the F-type channel permeability
• more Na+ enters the cell
• faster depolarisation

Question 14

Where is epinephrine produced?

Answer 14

adrenal medulla

Question 15

what does PS stimulation do?

Answer 15

decreases the rate of spread of excitation through the atria and AV node