What is happening during the phase labeled with the arrow?

The role of calcium currents in cardiac contractile cells is to .  The role of calcium currents in cardiac conductive cells is to .    Choose between: release neurotransmitter, bring the membrane potential to threshold, initiate action potential, prolong action potential, terminate action potential

During which phase of the cardiac cycle do the ventricles begin to contract while the semilunar valves remain closed ? Group of answer choices Isovolumetric contraction Ventricular ejection Ventricular filling

Number the structures involved in depolarization of heart from the one which depolarizes first (1) to the one which depolarizes last. A-V node Purkinje fibers right and left bundle branches atria

Draw these five graphs on the same set of axes: atrial autorhythmic cell action potential atrial cardiac contractile cell action potential ventricular autorhythmic cell action potential ventricular cardiac contractile cell action potential ventricular myocardial muscle tension

isovolumetric contraction isovolumetric relaxation ventricular filling ventricular ejection closed rises S1 drops depolarize S2 The first phase of the cardiac cycle is . This is when a lot of blood is in the atria, which causes atrial pressure to be higher than the ventricles. The atrioventricular valves open, and blood moves from the atria to the ventricles. At the end of this phase, the atria contract to maintain pressure and blood flow into the ventricles. As blood leaves the atria, the pressure in the atria As blood enters the ventricles, the pressure in the ventricles Towards the end of this phase, the pressure in the ventricles will exceed the pressure in the atria. At this point, the heart enters the second phase of the cardiac cycle: At this point, the AV valves shut, and we hear . The atria repolarize and the ventricles (due to the QRS complex of the ECG), causing ventricular contraction. Although contracting, it is not yet moving blood into the arteries. All 4 heart valves…

The cardiac action potential is substantially longer than a neuron potential due to: spontaneous depolarization Ca++ entry gap junctions myocardial contractility

which of the following is the first to occur during the period of ventricular systole? QRS complex, sharp rise and ventricular pressure, or blood leaving the ventricle.

Which structure(s) (if any) do NOT produce action potentials (APs)?   SA node   Atrial muscle   AV node   Ventricle muscle   These ALL produce APs

Congestive Heart Failure Why is this related to a valve or ventricular insufficiency? Where does the blood back up when it can't get out of the left ventricle?