Cardiovascular System

The period during which a heart chamber is contracting is called __.

The period during which a heart chamber is relaxing is called __.

During ventricular contraction, the AV valves remain __.

During ventricular relaxation, the AV valves remain __.

Heart sounds are due to __ in the heart tissues created by changes in blood flow.

The first sound of the cardiac cycle occurs when the __ valves are closing.

The second sound of the cardiac cycle occurs when the __ valves are closing.

The fibers of the cardiac conduction system are specialized __ tissue.

Normally, the __ node serves as the pacemaker of the heart.

The __ node is lcoated in the inferior portion of the interatrial septum.

The large fibers on the distal side of the AV node make up hte __.

The fibers that carry cardiac impulses from the interventricular septum into the myocardium are called __

An electrocardiogram is a recording of electrical changes occurring in the myocardium during the __.

Between cardiac cycles, cardiac muscle fibers remain __ with no detectable electrical changes.