cardiac cycle

How does the duration of systole compare at resting heart rate and during rapid heart rate exercise?

A is greater than B: During exercise, the systole duration shortens to allow for faster heart rates.

What is the comparison of blood volume in the ventricles during isovolumetric contraction and isovolumetric relaxation?

A is greater than B: The ventricles have more blood during IVC as contraction has not yet begun.

What happens to the volume of blood in the left ventricle when the left AV valve opens versus when it closes?

A is greater than B: Ventricular filling occurs after the AV valve opens, before it closes.

How do the durations of the refractory period in cardiac muscle and skeletal muscle compare?

A is greater than B: Cardiac muscle has a longer refractory period to prevent tetanus.

What is the comparison of the rate of ventricular filling in early diastole versus late diastole?

A is greater than B: Rapid filling occurs initially due to pressure differences.

How do the durations of the refractory period and contraction in cardiac muscle compare?

B is greater than A: The contraction duration is generally longer than the refractory period.

What is the comparison of impulse velocity through the bundle of His and Purkinje system versus the AV node?

A is greater than B: The Purkinje system conducts impulses more rapidly than the AV node.

How does the rate of depolarization in the SA node compare under parasympathetic versus sympathetic stimulation?

B is greater than A: Sympathetic stimulation increases the rate of depolarization.

What is the relation between stroke volume when end-diastolic volume equals 130 ml compared to 160 ml?

B is greater than A: A higher end-diastolic volume typically results in a higher stroke volume.

How does the volume of blood in the left ventricle change when the aortic valve opens versus when it closes?

A is greater than B: Blood is ejected during systole, reducing volume by closing.

What is the comparison of the duration of diastole at resting heart rate versus during rapid heart rate exercise?

A is greater than B: Diastole shortens with increased heart rates.

How do the spontaneous rates of depolarization in the SA node and ventricles compare?

A is greater than B: The SA node has a faster intrinsic depolarization rate.

What is the comparison of blood volume in the ventricles at the onset of isovolumetric contraction versus at the end of isovolumetric contraction?

A and B are equal: No volume change occurs during isovolumetric contraction.