ZOOL 2200: Quiz 8

Match each number on the figure below of an authorhythmic cell's action potential with what is occuring.

1.) Potassium channels slowly close and t-type calcium channels open 2.) L-type calcium channels open 3.) Voltage gated potassium channels open

Match the following parts of an ECG with their proper description.

P wave: atrial depolarization QRS complex: ventricular depolarization and atrial repolarization T wave: ventricular repolarization PQ segment: AV nodal delay QT segment: ventricular systole TQ interval: ventricular diastole

The wall of the left ventricle is much thicker than the wall of the right ventricle because:

the left ventricle pumps blood to the systemic circuit which is a high pressure circuit.

The cardiac contractile cells' action potentials have a plateau phase caused by:

the opening of calcium channels.

Which of the following is true of parasympathetic activity to the SA node?

T-Type calcium channel opening is decreased.

Match each phase of the cardiac with what is occuring.

Ventricular filling: AV valves are open and semilunar valves are closed Isovolumetric ventricular contraction: AV and semilunar valves are closed and the ventricles are in systole Ventricular ejection: semilunar valves are open and AV vales are closed Isovolumetric ventricular relaxation: AV and semilunar valves are closed and the ventricles are in diastole

Cardiac muscle differs from skeletal muscle in:

all of the above are found only in cardiac muscle.

The opening and closing of the atrioventricular valves are due to:

differences in pressure across the valves.

Stroke volume or the amount of blood pumped out of the ventricles per heart beat =

end diastolic volume - end systolic volume

Which of the following would DECREASE cardiac output?

increasing parasympathetic activity to the SA node.