71) The semilunar valves are closed when
A) the ventricles are contracting.
B) the ventricles are relaxing.
C) the atrioventricular valves are closed.
D) atria are contracting.
72) The atrioventricular node is located in the
A) right atrium, just inferior to the opening of the superior vena cava.
B) inferior part of the interatrial septum.
C) interventricular septum, near the heart base.
D) walls of the ventricles, with the other Purkinje fibers.
73) Of the following heart chambers, which is most affected by hypertrophic cardiomyopathy?
A) right atrium
B) right ventricle
C) left ventricle
D) left atrium
74) The left ventricular wall of the heart is thicker than the right ventricular wall so that it can
A) accommodate a greater volume of blood.
B) expand the thoracic cage during diastole.
C) pump blood with greater pressure.
D) pump blood through a smaller valve.
75) During left ventricular systole, blood exits the heart to enter the
A) aorta.
B) pulmonary trunk.
C) pulmonary vein.
D) venae cavae.
76) To listen for the aortic semilunar valve on the chest wall, one would place the stethoscope in the
A) second intercostal space to the right of the sternum.
B) second intercostal space to the left of the sternum.
C) fifth intercostal space inferior to the left nipple.
D) fifth right intercostal space.
77) Which of the following statements about fetal heart development is
false?
A) The four heart chambers first develop during the third trimester.
B) The heart begins as a pair of tubes in the midline of the thorax.
C) The heart develops from mesodermal mesenchyme.
D) The two atria are connected by a foramen ovale until birth.
78) The tricuspid valve is closed
A) while the ventricle is in diastole.
B) by movement of blood from atrium to ventricle.
C) while the atrium is contracting.
D) when the ventricle is in systole.
79) Which of the following is
not
an age-related change in the heart?
A) thinning of the valve cusps
B) decline in cardiac reserve
C) fibrosis of cardiac muscle
D) atherosclerosis
80) In the pericardial sac, the ________ lies directly deep to the fibrous pericardium.
A) pericardial cavity
B) visceral layer of serous pericardium
C) parietal layer of the serous pericardium
D) epicardium
81) This blood vessel is located in the anterior interventricular sulcus.
A) anterior cardiac vein
B) great cardiac vein
C) middle cardiac vein
D) small cardiac vein
82) The cardiac centers that control heart rate are located in the
A) cerebral cortex of the temporal lobe.
B) medulla oblongata of the brain stem.
C) pituitary gland of the diencephalon.
D) thoracic segments of the spinal cord.