The Heart

Which of these structures returns blood to the right atrium?

a. coronary sinus

b. inferior vena cava

c. superior vena cava

d. Both b and c are correct.

e. All of these are correct.

e.

The valve located between the right atrium and the right ventricle is the

a. aortic semilunar valve.

b. pulmonary semilunar valve.

c. tricuspid valve.

d. bicuspid (mitral) valve.

c.

The papillary muscles

a.are attached to chordae tendineae.

b. are found in the atria.

c. contract to close the foramen ovale.

d. are attached to the semilunar valves.

e. surround the openings of the coronary arteries.

a.

Given these blood vessels:

(1) aorta

(2) inferior vena cava

(3) pulmonary trunk

(4) pulmonary vein

Choose the arrangement that lists the vessels in the order a red blood cell would encounter them going from the systemic veins to the systemic arteries.

a. 1,3,4,2

b. 2,3,4,1

c. 2,4,3,1

d. 3,2,1,4

e. 3,4,2,1

b.

The bulk of the heart wall is

a. epicardium.

b. pericardium.

c. myocardium.

d. endocardium.

e. exocardium.

c.

Cardiac muscle has

a. sarcomeres.

b. a sarcoplasmic reticulum.

c. transverse tubules.

d. many mitochondria.

e. All of these are correct.

e.

Action potentials pass from one cardiac muscle cell to another

a. through gap junctions.

b. by a special cardiac nervous system.

c. because of the large voltage of the action potentials.

d. because of the plateau phase of the action potentials.

e. by neurotransmitters.

a.

During the transmission of action potentials through the conducting system of the heart, there is a temporary delay at the

a. bundle branches.

b. Purkinje fibers.

c. AV node.

d. SA node.

e. AV bundle.

c.

Given these structures of the conducting system of the heart:

(1) atrioventricular bundle

(2) AV node

(3) bundle branches

(4) Purkinje fibers

(5) SA node

Choose the arrangement that lists the structures in the order an action potential passes through them.

a. 2,5,1,3,4

b. 2,5,3,1,4

c. 2,5,4,1,3

d. 5,2,1,3,4

e. 5,2,4,3,1

d.

Purkinje fibers

a. are specialized cardiac muscle cells.

b. conduct impulses much more slowly than ordinary cardiac muscle.

c. conduct action potentials through the atria.

d. connect the SA node and the AV node.

e. ensure that ventricular contraction starts at the base of the heart.

a.

T waves on an ECG represent

a. depolarization of the ventricles.

b. repolarization of the ventricles.

c. depolarization of the atria.

d. repolarization of the atria.

b.

The greatest amount of ventricular filling occurs during

a. the first one-third of diastole.

b. the middle one-third of diastole.

c. the last one-third of diastole.

d. ventricular systole.

a.

While the semilunar valves are open during a normal cardiac cycle, the pressure in the left ventricle is

a. higher than the pressure in the aorta.

b. lower than the pressure in the aorta.

c. the same as the pressure in the left atrium.

d. lower than the pressure in the left atrium.

a.

Blood flows neither into nor out of the ventricles during

a. the period of isovolumetric contraction.

b. the period of isovolumetric relaxation.

c. diastole.

d. systole.

e. Both a and b are correct.

e.

Stroke volume is the

a. amount of blood pumped by the heart per minute.

b. difference between end-diastolic and end-systolic volume.

c. difference between the amount of blood pumped at rest and that pumped at maximum output.

d. amount of blood pumped from the atria into the ventricles.

b.

Cardiac output is defined as

a. blood pressure times peripheral resistance.

b. peripheral resistance times heart rate.

c. heart rate times stroke volume.

d. stroke volume times blood pressure.

e. blood pressure minus peripheral resistance.

c.

Pressure in the aorta is at its lowest

a. at the time of the first heart sound.

b. at the time of the second heart sound.

c. just before the AV valves open.

d. just before the semilunar valves open.

d.

Just after the dicrotic notch on the aortic pressure curve,

a. the pressure in the aorta is greater than the pressure in the left ventricle.

b.the pressure in the left ventricle is greater than the pressure in the aorta.

c. the pressure in the left atrium is greater than the pressure in the left ventricle.

d. the pressure in the left atrium is greater than the pressure in the aorta.

e. blood pressure in the aorta is 0 mm Hg.

a.

The "lubb" sound (first heart sound) is caused by the

a. closing of the AV valves.

b. closing of the semilunar valves.

c. blood rushing out of the ventricles.

d. filling of the ventricles.

e. ventricular contraction.

a.

Increased venous return results in

a. increased stroke volume.

b. increased cardiac output.

c. decreased heart rate.

d. Both a and b are correct.

d.

Parasympathetic nerve fibers are found in the _________ nerves and release _________ at the heart.

a. cardiac, acetylcholine

b. cardiac, norepinephrine

c. vagus, acetylcholine

d. vagus, norepinephrine

c.

Increased parasympathetic stimulation of the heart

a. increases the force of ventricular contraction.

b. increases the rate of depolarization in the SA node.

c. decreases heart rate.

d. increases cardiac output.

c.

Because of the baroreceptor reflex, when normal arterial blood pressure decreases, the

a. heart rate decreases.

b. stroke volume decreases.

c. frequency of afferent action potentials from baroreceptors decreases.

d. cardioregulatory center stimulates parasympathetic neurons.

c.

A decrease in blood pH and an increase in blood carbon dioxide levels result in

a. increased heart rate.

b. increased stroke volume.

c. increased sympathetic stimulation of the heart.

d. increased cardiac output.

e. All of these are correct.

e.

An increase in extracellular potassium levels can cause

a. an increase in stroke volume.

b. an increase in force of contraction.

c. a decrease in heart rate.

d. Both a and b are correct.

c.