Cardiac Cycle Flashcards
Refractory period:
Occurs during an action potential.
The membrane is less responsive to another action potential.
Skeletal muscle fiber:
Have a very short action potential.
2msec.
Each action potential leads to:
EC Coupling.
Filament sliding.
Muscle fiber contractions.
Each action potential causes the release of :
Ca++ into the sarcoplasm.
Closely spaced action potential results in:
A higher Ca++ concentration in the sarcoplasm.
They prolong the contraction and increase the force of contraction.
When an action potential reaches a certain frequency
A single sustained contraction is maintained.
What are the basics for all body movements:
Sustained contractions.
The prolonged action potential in cardiac cells ensures that:
Sustained contractions cannot occur in cardiac muscle cells.
The contraction and action potential in a cardiac cell is completed:
At about the same time.
Cardiac muscle must _____ before they can contract:
Relax.
Cardiac cycle:
The events that occur within the heart during one heartbeat.
What gets released during an action potential:
Ca++
Systole is the term for:
Contraction.
Diastole is the term for:
Relaxation.
At resting heart rate, diastole:
Lasts longer than systole.
Systole & Diastole:
Alter the blood pressure within the heart chambers and create pressure gradients that drive blood flow through the heart and vasculature.
Pressure differences can also:
Open and close the heart valves.
Semilunar valves:
Valves between ventricles and arteries.
The right semi-lunar valve lies:
Between the right ventricle & Pulmonary trunk.
The left semi-lunar valve lies:
Between the left ventricle & aorta.
When the AV valve is open:
There is higher pressure in the atrium.
There is lower pressure in the ventricle.
When the semi-lunar valve is open:
There is higher pressure in the ventricle.
There is lower pressure in the atries.
When the AV valve is closed:
There is lower pressure in the atrium.
There is higher pressure in the ventricle.
When the semi-lunar valve is closed:
There is lower pressure in the ventricle.
There is higher pressure in the atries.
Number of phases in the cardiac cycle:
4.
Phase 1 ( Ventricular filling):
