In the early fetal life the main site for red blood cell formation is:
1. bone marrow
2. kidney
3. liver
4. spleen

Tissue death (necrosis) due to inadequate blood supply to the affected area, such as the heart, is:

A chest pain or pressure, usually due to not enough blood flow to the heart muscle, is known as:

What is the percentage of atrial blood that flows into the ventricles without atrial systole?

Atria can completely empty during ventricular filling due to:
1. A-V node
2. A-V bundle
3. S-A node
4. Purkinje fibers

The period that extends from the onset of atrial depolarization until the onset of ventricular depolarization is shown in an ECG as:
1. QRS complex
2. S-T interval
3. P-Q interval
4. QRS-T interval

The arrhythmia that results in cardiac arrest followed by death in the absence of treatment and therefore considered most serious is:
1. Tachycardia
2. Sinus bradycardia
3. Atrial flutter
4. Ventricular fibrillation

The venous return to the heart is facilitated by:
1. valves
2. inspiration
3. skeletal muscle
4. all of these

A condition where the arteries become narrowed and hardened due to a buildup of plaque around the artery wall is called as:
1. arteriosclerosis
2. phlebitis
3. atherosclerosis
4. plaque

During the cardiac cycle the tricuspid and bicuspid valves get closed when:
1. when pressure inside the ventricles is at its lowest
2. when pressure inside the atria is greater than that inside the ventricles
3. when ventricular pressure exceeds that of the atria
4. when pressure is greater in the aorta than in the left ventricle