Control of cardiac output Flashcards
(15 cards)
What are the 4 stages of diastole?
Isovolumetric relaxation
Rapid ventricular filing
Diastasis (reduced ventricular filling)
Atrial systole
What are the 2 stages of systole?
Isovolumetric contraction
Ejection
What does the horizontal scale indicate on a pressure-volume loop?
Ventricular volume
What does the vertical scale indicate on a pressure-volume loop?
Ventricular pressure
What does the ‘a’ wave represent in JVP?
Atrial systole
What does the ‘c’ wave represent in JVP?
Bulging of the tricuspid valve
What does the ‘x’ descent represent in JVP?
Atria relax (pressure reduced)
What does the ‘v’ wave represent in JVP?
Atrial filling during ventricular systole
What does the ‘y’ descent represent in JVP?
Passive ventricular filling during diastole
Define preload.
The degree of ventricular cardiomyocyte stretch at the end of diastole
Preload is determined by what factor?
EDV
In what way would aortic valve stenosis affect preload?
Increase preload
In what way would atrial fibrillation affect preload?
Decrease preload
What is the relationship between heart rate + contractility (inotropy)?
What effect is this called?
Increased heart rate increases contractility (inotropy)
Bowditch effect
Define afterload.
The force or stress on cardiomyocytes during systole - the load that the heart must eject against
