The semilunar valves will open during a normal cardiac cycle when the pressure in the left ventricle is
1. greater than the pressure in the aorta.
2. less than the pressure in the aorta.
3. the same as the pressure in the aorat.
4. less than the pressure in the left atrium.

Stroke volume is the
1. amount of blood pumped by the left ventricle per minute.
2. difference between end-diastolic and end-systolic volume.
3. difference between systolic and diastolic blood pressure.
4. amount of blood pumped by atrial systole into the ventricles.

Cardiac output is defined as
1. blood pressure X stroke volume.
2. peripheral resistance X heart rate.
3. heart rate X stroke volume.
4. Systolic pressure – diastolic pressure.

Also sometimes called as the ‘widow maker’ the anterior interventricular artery is a branch of the
1. left circumflex artery.
2. right anterior descending artery.
3. left coronary artery.
4. right coronary artery.

What is most likely to happen if the SA node suddenly stops generating the impulse?
1. The heart will stop.
2. The ventricles will contract, but the atria will stop.
3. Another part of the heart, possibly the AV node, will become the pacemaker.
4. The atria will keep contracting, but the ventricles will stop.

Identify the correct statement regarding the cardiac muscle:
1. Cardiac muscle does not have sarcoplasmic reticulum.
2. Cardiac muscle has a plateau phase in repolarization called the plateau phase.
3. Cardiac muscle has a shorter refractory period than skeletal muscle.
4. Depolarization of cardiac muscle occurs when ${\mathrm{K}}^{+}$ and ${\mathrm{Na}}^{+}$ diffuse into the cell.

A slower heart rate or bradycardia would most likely be the result of:
1. ectopic action potentials in the atria
2. damage to the tricuspid valve
3. excessive sympathetic stimulation
4. excessive parasympathetic stimulation

The location of the human heart is most accurately described as:

Pericardial fluid is the serous fluid secreted by the serous layer of the pericardium into the pericardial cavity and it serves to:
1. reduce friction between the pericardial membranes.
2. lubricate the heart valves.
3. replace any blood that is lost.
4. provide oxygen and nutrients to the endocardium.

All cardiac veins empty into the ______, which then empties into the ______.
1. coronary sinus; left atrium
2. coronary sinus; right atrium
3. great cardiac vein; right atrium
4. great cardiac vein; left atrium