Revision Session Flashcards
What is the cardiac cycle duration?
850ms
How much does atrial contraction contribute to ventricular filling?
approx 5ml
more important at higher heart rates
Draw graph of overview of left cardiac cycle and explain it
- aortic pressure
- ventricular pressure
- atrial pressure
- left ventricle volume
- ECG
- heart sounds
see lectures
What are the pressures ranges for the following?
- aortic
- pulmonary
- left ventricular
- right ventricular
- left atrial
- right atrial
- 80-120
- 10-25
- 0-120
- 0-25
- 0-10
- 0-4
What is a normal EDV and ESV?
and therefore stroke volume?
EDV = 120 ESV = 50 SV = 70
What colours are the ECG leads?
right leg = black
left leg = green
right arm = red
left arm = yellow
Draw graph that shows ECG trace, SAN action potential, atrial cell action potential, ventricular cells action potential.
See ECG lecture
Which proteins are responsible for the reuptake of Ca2+ into the SR?
Phospholamban
SERCA
Apart from the 5 factors that affect venous return, what other 2 factors affect EDV?
Atrial contraction - In exercise, filling time is shorted. Atria contract to ensure efficient filling, SNS of atrial muscle increases force of contraction and EDV
Heart rate above 180bpm - atrial contraction can no longer compensate, EDV decreases
What are the intrinsic and extrinsic factors that affect cardiac output?
Intrinsic = EDV and length dependent increase in calcium sensitivity Extrinisic = ESV and length independent increase in calcium sensitivity
What parts of the apparatus become more sensitive to calcium when sympathetic activity is increased?
Tn-C
Define the following:
- chronotropy
- inotropy
- lusitropy
- automaticity
chronotropy = firing of SAN inotropy = contraction of myocardium lusitropy = relaxation of myocardium automaticity = ability to spontaneusly generate electrical impulse
