Heart As A Pump Flashcards
1
Q
Cardiac output equation
A
CO=HRxSV
2
Q
Stroke volume
A
The volume of blood to exit either the ventricles only every heart beat
3
Q
Diastole
A
When the heart is relaxed
4
Q
Systole
A
When the heart is contracted
5
Q
Role of the non contractile cells:
A
Conduct action potentials across the heart which co-ordinate contractions
6
Q
Order of conduction in the heart
A
- SAN SELF-generates action potentials
- Wave of depolarisation across cardiac cells in the atriums stimulates contractions
- Bachmann’s/intrinsic bundle contact impulse to L atrium
- Depolarisation reaches AVN (circle of his) which slows down the wave
- Atria fully contract
- Travels down purkinje fibres, ventricular depolarisation a d contraction
7
Q
Parasympathetic nervous system effect on the heart
A
Increase AVN and SAN impulses to slow heart rate
8
Q
What modifies the SAN activity?
A
Autonomic nervous system
9
Q
What effect does the sympathetic nervous system have on the heart?
A
Increases SAN activity to increase both cardiac output and peripheral vascular resistance
10
Q
What’s does SAN stand for?
A
Sinoatrial node
11
Q
What does AVN stand for
A
Atrioventricular node
