Cardiac cycle Flashcards
what is the cardiac excitation cycle
1) action potential enters from adjacent cell
2) voltage gated ca channels open and ca enters
3) ca induces ca release trhough Ryr channels
4) local release cuases ca spark
5) sumed ca sparks create ca signal
6) ca ions bind to troponin to intial contraction
7) realation occurs when ca unbinds troponin
8) ca is pumped back in SR
9) ca is echnged with Na by the NCX tansporter
10)NA gradient is maintaned by NA/K atpase
what is a cardaic cycle
coordination of electrical and mechanical events that occur within one heartbeat
what is one cardiac cycle defined as
one period that goes from the begging of one heart beat to the begging of the next (p-p) or R-R
what are the two phases of the heart cycle and define them
systole: time of contraction
Diastole: time of relaxtation
what are the cardio vascular events recorded during the cardiac cylcle
- pressures
- ventricular volumes
- ECG
- phonocardiogram
what is the normal heart rate in adults and according to this what is the length of the cardiac cycle
- 70-75 beats /. min = 0.8s/cycle
what are the phases of the cardiac cycle bassed of og wiggers diagram
A. atrial systole
B isovolumetric ventricular contraction
C. Rapif ventricular ejection
D. SLower ventricular ejection
E. isovolumetric ventricular relaxation
F. Rapid ventricular filling
G.Slower ventricular filling
what types of pressures are recorded during the cardaic cycle
- atrial
- ventricular
- aortic
what happes during ventricular systole based on wiggers graph
- isovolumetric ventricular contraction
- Rapid ventricular ejection
- reduced ventricular ejection
what happens during ventricular diastole based on wiggers graph
- isovolumetric ventricular relaxation
- rapid ventricular filling
- reduced ventricular filling
how do the pressures of the right and left heart differ and why
- the right heart is a lower pressure pump because its a shorter circuit
- the left heart is a higher pressure pump because its a longer circuit that exerts greater resistance
what are the three waves of the atrial pressure curve
- A wave
- V wave
-C wave
what does the A wave of the atrial pressure curve represent
-what happens to atrial pressure and where is blood moving?
atrial contraction: atrial pressure increase> blood moves thorugh the ventrcles thorugh the AV valves
what percentage of ventricular filling does the atrium contribute and when is this most important
15-20% of ventricular filling and is imporntant during times of distress
what does the c wave of the atrial pressure curve represent
- occurs during isovolumetric ventricular contraction
- rapid increase in ventricualr pressure causes the AV valves to bulge inwardly» atrial volume decreases» atrial pressure increases
what does the V wave represent in the atrial pressure curve
-what happens to the AV valves
- occurs with atrial filling»_space; Av valves are closed and the atria are filling
what does the ventricular pressure curve demonstrate
changes in ventricular pressure during systole and diastole
what are the 4 phases demonstrated in the Ventricular pressure curve
- isovolumetric contraction
- ejection (systole)
- isovolumetric ventricular relaxation
- ventricular filling
what occurs during isovolumetric ventricular contraction (2) in the ventricular pressure curve
- what happens to the valves and why
What happen to the pressure
- AV valves close when LVP>LAP» ventricles begin to contract isometrically» pressure rises quickly
- when LVP > AoP» semilunar valves open» ejection of blood
what are the two phases of ejection in the ventricular pressure curve and where is blood ejected
- the two phases are rapid (3)and slower (4)ejection and and during this phase blood is pumped out if the ventricles into the aorta or pulmonary artery
what is occuring during the isovolumetric relaxation (5) phase of the ventricular pressure curve
What happens to the valves and why
What happens to the pressure
- when LVP<AoP>> semilunar valves close</AoP>
- large drop in ventricular pressure
- ventricle relaxing
whats occuring during ventricular filling phase of the ventricular pressure curve? ( 6 and &7)
- what is happens to the valves
What is the pressure in the ventricle
What phases do six and seven make up
- when LVP < LAP»_space; AV valves open
- ventricles fill with blood
- rapid filling (6) and slower filling phase (7)
- ventricular pressures reamin very low (,10mmhg) in this phase
what does the aortic pressure curve represent
- changes in aortic ( arterial pressure) during one cardiac cycle
in the aortic pressure curve what happens as the heart fill with blood ( end of diastole)
- aortic pressure declines (1)