ch 20 review & comp quiz

Given these structures of the conduction 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) 5,2,1,3,4

Increased venous return results in A) increased stroke volume. B) increased cardiac output. C) decreased heart rate. D) both A and B.

D) both A and B.

The fibrous pericardium A) is in contact with the heart. B) is a serous membrane. C) is also known as the epicardium. D) forms the outer layer of the pericardial sac. E) all of the above.

D) forms the outer layer of the pericardial sac.

Which of these does not correctly describe the skeleton of the heart? A) electrically insulates the atria from the ventricles B) provides a rigid source of attachment for the cardiac muscle C) functions to reinforce or support the valve openings D) is composed mainly of cartilage

D) is composed mainly of cartilage

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 before the semilunar valves open.

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) are attached to chordae tendineae.

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 between the SA node and the AV node. E) ensure that ventricular contraction starts at the base of the heart.

A) are specialized cardiac muscle cells.

The "lubb" sound (first heart sound) of the heart 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) closing of the AV valves.

While the semilunar valves are open during a normal cardiac cycle, the pressure in the left ventricle is A) greater than the pressure in the aorta. B) less than the pressure in the aorta. C) the same as the pressure in the left atrium. D) less than the pressure in the left atrium.

A) greater than the pressure in the aorta.

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) the first one-third of diastole.

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

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) through gap junctions.

The pressure within the left ventricle fluctuates between A) 120 and 80 mm Hg. B) 120 and 0 mm Hg. C) 80 and 0 mm Hg. D) 20 and 0 mm Hg.

B) 120 and 0 mm Hg.

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 in going from the systemic veins back 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) 2,3,4,1

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

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) repolarization of the ventricles.

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) AV node.

An increase in extracellular potassium levels could cause A) an increase in stroke volume. B) an increase in the force of contraction. C) a decrease in heart rate. D) both a & b

C) a decrease in heart rate.

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 the heart rate. D) increases cardiac output.

C) decreases the heart rate.

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) heart rate times stroke volume.

Muscular ridges on the interior surface of the auricles are called A) trabeculae carneae. B) crista terminalis. C) musculi pectinati. D) endocardium. E) papillary muscles.

C) musculi pectinati.

The bulk of the heart wall is A) epicardium. B) pericardium. C) myocardium. D) endocardium. E) exocardium.

C) myocardium.

Because of the baroreceptor reflex, when normal arterial blood pressure decreases A) heart rate decreases. B) stroke volume decreases. C) the frequency of afferent action potentials from baroreceptors decreases. D) the cardioregulatory center stimulates parasympathetic neurons. E) all of the above.

C) the frequency of afferent action potentials from baroreceptors decreases.

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) tricuspid valve.

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) vagus, acetylcholine

Which of these conditions observed in an electrocardiogram suggests that the AV node is not conducting action potentials? A) complete lack of the P wave B) complete lack of the QRS complex C) more QRS complexes than P waves D) a prolonged PR interval E) P waves and QRS complexes are not synchronized

E) P waves and QRS complexes are not synchronized

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 E) all of the above

E) all of the above

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 the above.

E) all of the above.

Cardiac muscle has A) sarcomeres. B) a sarcoplasmic reticulum. C) transverse tubules. D) many mitochondria. E) all of the above.

E) all of the above.

Blood flows neither into nor out of the ventricles during A) the period of isovolumic contraction. B) the period of isovolumic relaxation. C) diastole. D) systole. E) both A and B.

E) both A and B.