Control of cardiac function Flashcards
1
Q
What is cardiac output (CO)?
A
Volume of blood pumped by the heart each minute
2
Q
What formula is used to determine CO?
A
heart rate (HR) x stroke volume (SV)
L/min
3
Q
What formula is used to determine BP?
A
CO x total peripheral resistance (TPR)
4
Q
What factors affect CO?
A
- heart rate (HR)
- stroke volume (SV)
5
Q
How does heart rate affect CO?
A
- ANS
- Hormones
- Atrial stretch
- Drugs
- Ion conc
- Body temp
6
Q
How does stroke volume affect CO?
A
- end-diastolic volume
- end-systolic volume
EDV - ESV = SV
EDV increases → SV increases → CO increases
7
Q
How does end-diastolic volume affect CO?
A
- filling time of blood increases
- greater preload which increases SV and therefore CO
8
Q
How does end-systolic volume affect CO?
A
- increase in contractility → decrease in ESV → increase in CO
- increase in afterload → increase in ESV → decrease in CO
9
Q
What does the cardioacceleratory centre do?
A
- stimulates cardiac function by regulating HR & SV
- via sympathetic stimulation from the cardiac accelerator nerve
10
Q
What does the cardioinhibitory centre do?
A
- slows cardiac function by decreasing HR & SV
- via parasympathetic stimulation from the vagus nerve
