The fraction of an anticoagulated blood sample called the "buffy coat" contains
1. red blood cells
2. white blood cells
3. platelets
4. white blood cells and platelets

The cause of “aplastic anemia" would be:
1. lack of iron content or iron absorption from the diet
2. destruction of the bone marrow, perhaps by chemicals in the environment or chemotherapy
3. high altitude
4. inadequate vitamin B₁₂ absorption from the diet because the intrinsic factor is absent

Thrombocytes:
1. have a life span of about 60 days
2. are also called megakaryocytes
3. release a chemical called serotonin that constricts blood vessels
4. are not involved in hemostasis

The rarest white blood cells are:

What is true regarding pulmonic and aortic semilunar valves in the human heart?
1. They prevent the backflow of blood from the ventricles into the atria
2. They are open during the relaxation phase of the ventricles
3. They are held tightly closed by papillary muscles and chordae tendineae
4. They regulate the passage of blood from the ventricles into the pulmonary artery and the aorta

Which of the following causes the second heart sound [dub]?
1. opening of the AV valves at the start of diastole
2. closing of the AV valves at the start of systole
3. opening of the semilunar valves at the start of systole
4. closing of the semilunar valves at the start of diastole

The sinoatrial node is the normal pacemaker of the human heart because it:

What is the ejection fraction that is achieved by the left ventricle in a healthy heart?
1. 10(--)15%
2. 25(--)33%
3. 60(--)70%
4. 98(--)100%

Veins are said to have a higher ____ than arteries because they expand more easily and a higher ___________ because they contain more blood.
1. compliance; capacitance
2. elasticity; compliance
3. elasticity; capacitance
4. None of the above

How can adrenaline have different effects on blood vessels - vasodilation in skeletal muscle but vasoconstriction in the skin?
1. sympathetic fibers secrete epinephrine in the muscle and acetylcholine in the skin
2. bradykinin stimulates constriction of arterioles in the dermis
3. the muscles have cholinergic sympathetic fibers and the skin has adrenergic fibers
4. the muscle arterioles and the skin arterioles have different types of receptors for adrenaline