CHAPTER 20

The right side of the heart receives blood from the body and pumps through _________ circulation to the lungs.

pulmonary

what are the functions of the heart?

regulating blood supply to tissues depending on needgenerating blood pressure through contractionrouting blood to either the pulmonary or systemic circulations

The heart -is a four-chambered muscular pump.-is posterior to the trachea.-is lined with an epithelial layer called epicardium.-lies mostly to the right of the midline of the sternum.-has a superior apex and an inferior base.

is a four-chambered muscular pump.

A serious condition in which a large amount of fluid accumulates in the pericardial cavity and puts pressure of the heart is

cardiac tamponade.

Another name for the visceral pericardium is the

epicardium

Which of the following pairs is mismatched? -endocardium - covers the inner surfaces of the heart-myocardium - cardiac muscle-trabeculae carneae - interior walls of ventricles-pectinate muscles - muscles that close valves

pectinate muscles - muscles that close valves

A stab wound into the heart can result in cardiac tamponade. This means that

the heart is compressed by blood in the pericardial sac.

Which of the following layers forms the bulk of the heart wall? -epicardium-pericardium-endocardium-myocardium-visceral pericardium

myocardium

Blood vessels enter and exit from the _____ of the heart.

base

The great cardiac vein and middle cardiac vein empty into a venous cavity called the

coronary sinus.

Occlusion of which of the following would primarily damage the posterior wall of the heart? -circumflex artery-pulmonary artery-right marginal artery-coronary sinus artery-right coronary artery

circumflex artery

A direct connection between arteries is called a/an

anastamosis.

Coronary artery disease can diminish myocardial blood flow resulting in the death of myocardial cells. This condition is known as a myocardial

infarction.

Angina pectoris is chest pain caused by reduced

blood supply to cardiac muscle.

Which of the following is NOT a major opening into the right atrium? -pulmonary vein-inferior vena cava-superior vena cava-coronary sinus

pulmonary vein

What is the foramen ovale?

An opening between the right and left atria in the embryo and fetus.

The AV valve that is located on the same side of the heart as the origin of the aorta is the

bicuspid or mitral valve.

Contraction of the papillary muscles would

prevent the AV valves from protruding into the atria.

The chordae tendineae

connect the flaps of the AV valves to the papillary muscles.

Blood in the superior vena cava will enter the _____.

right atrium

Which blood vessel carries blood from the left ventricle?

aorta

Which vessels transport blood to the right and left lungs?

pulmonary arteries

Which of the following heart chambers is correctly associated with the blood vessel that enters or leaves it? -right atrium - pulmonary veins-left atrium - aortaright ventricle - pulmonary trunk-left ventricle - superior -vena cava and inferior vena cava-right atrium - aorta

right ventricle - pulmonary trunk

Which of the following phrases would apply to cardiac muscle cells? -are organized in parallel columns or bundles-contain actin but no myosin-develop a significant oxygen debt during systole-are multinucleated like skeletal muscle cells-possess special cell-to-cell contacts called intercalated discs

possess special cell-to-cell contacts called intercalated discs

The "pacemaker" of the heart is the

SA node

Which of the following sequences for the conducting system is correct? -AV node, AV bundle, SA node, Purkinje fibers, bundle branches-Purkinje fibers, bundle branches, AV node, AV bundle, SA node-SA node, AV node, AV bundle, bundle branches, Purkinje fibers-SA node, AV bundle, AV node, bundle branches, Purkinje fibers

SA node, AV node, AV bundle, bundle branches, Purkinje fibers

The cardiac electrical impulse normally begins spontaneously in the SA node because

this area produces action potentials more rapidly than any other portion of the conduction system.

Ventricular contraction begins at the

apex of the heart.

The spontaneous opening of sodium channels marks the beginning of ____ of a myocardial cell.

depolarization

When a pacemaker potential in the SA node reaches threshold,

many voltage-gated Ca2+ channels open.

Calcium channel blockers are frequently used to

treat tachycardia or other arrhythmias.

Which of the following is mismatched? -opening of sodium channels - depolarization-closing of calcium channels - plateau phase-opening of potassium channels - rapid repolarization-closure of sodium channels - early repolarization-opening of calcium channels - plateau phase

closing of calcium channels - plateau phase

In a normal electrocardiogram, the

QRS complex results from ventricular depolarization.

Of the types of damage resulting from a myocardial infarction, which is most likely to cause the greatest increase in the Q-T interval? -infarction in the AV nodeleft bundle branch block-infarction affecting the SA node-tachycardia-ectopic focus

left bundle branch block

In the cardiac cycle,

all four chambers of the heart are in diastole at the same time.

The product of the stroke volume times the heart rate is known as the

cardiac output.

Mean arterial pressure is

cardiac output times peripheral resistance.

Within normal limits, an increase in preload leads to

an increase in cardiac output and force of left ventricular contraction.

Stimulation of the heart via the sympathetic nerves would

increase the force of ventricular contraction.

Excess potassium ions in cardiac tissue cause

a decrease in the frequency of action potentials in the conduction system.

The right side of the heart receives blood from the body and pumps through _________ circulation to the lungs.

pulmonary

Which of the following is NOT a function of the heart?A. providing a location for gas exchange between oxygen and carbon dioxideB. regulating blood supply to tissues depending on needC. generating blood pressure through contractionD. routing blood to either the pulmonary or systemic circulations

A

The heartA. is a four-chambered muscular pump.B. is posterior to the trachea.C. is lined with an epithelial layer called epicardium.D. lies mostly to the right of the midline of the sternum.E. has a superior apex and an inferior base.

A

The epicardiumA. covers the surface of the heart.B. lines the walls of the ventricles.C. is known as the fibrous pericardium.D. attaches inferiorly to the diaphragm.E. is also called endocardium.

A

E.Z. Goen is admitted to the cardiac unit with a diagnosis of endocarditis. When E.Z. asks the nurse where the infection is located, the nurse replies that the infection is inA. the outer layer of the heart wall.B. the inner lining of the heart.C. a membranous sac that encloses the heart wall.D. the muscular layer of the heart.E. the lining of the mediastinum.

B

Which of the following pairs is mismatched?A. endocardium - covers the inner surfaces of the heartB. myocardium - cardiac muscleC. trabeculae carneae - interior walls of ventriclesD. pectinate muscles - muscles that close valvesE. chordae tendineae - connective tissue strings that connect to cusps of valves

D

Which of the following layers forms the bulk of the heart wall?A. epicardiumB. pericardiumC. endocardiumD. myocardiumE. visceral pericardium

D

Blood vessels enter and exit from the _____ of the heart.A. apexB. baseC. auriclesD. trigoneE. inferior aspect

B

The great cardiac vein and middle cardiac vein empty into a venous cavity called the

coronary sinus

Occlusion of which of the following would primarily damage the posterior wall of the heart?A. circumflex arteryB. pulmonary arteryC. right marginal arteryD. coronary sinus arteryE. right coronary artery

A

A direct connection between arteries is called a/an

anastamosis

Coronary artery disease can diminish myocardial blood flow resulting in the death of myocardial cells. This condition is known as a myocardial

infarction

Angina pectoris is chest pain caused by reduced

blood supply to cardiac muscle.

Which of the following is NOT a major opening into the right atrium?A. pulmonary veinB. inferior vena cavaC. superior vena cavaD. coronary sinus

A

What is the foramen ovale?

An opening between the right and left atria in the embryo and fetus.

The AV valve that is located on the same side of the heart as the origin of the aorta is the

bicuspid or mitral valve

Contraction of the papillary muscles would

prevent the AV valves from protruding into the atria

Blood in the superior vena cava will enter the _____.

right atrium

Which blood vessel carries blood from the left ventricle?A. aortaB. right atriumC. pulmonary trunkD. pulmonary arteriesE. pulmonary veins

A

Which vessels transport blood to the right and left lungs?A. aortaB. right atriumC. pulmonary trunkD. pulmonary arteriesE. pulmonary veins

D

Which of the following heart chambers is correctly associated with the blood vessel that enters or leaves it?A. right atrium - pulmonary veinsB. left atrium - aortaC. right ventricle - pulmonary trunkD. left ventricle - superior vena cava and inferior vena cavaE. right atrium - aorta

C

Cardiac muscle cellsA. have smooth ER but no T tubules.B. form the heart valves.C. are maintained by an extensive capillary network.D. develop a significant oxygen debt during systole.E. do not contain actin and myosin like skeletal muscle cells.

C

Action potentials pass from one myocardial cell to another through areas of low electrical resistance called

gap junctions

Which of the following sequences for the conducting system is correct?A. AV node, AV bundle, SA node, Purkinje fibers, bundle branchesB. Purkinje fibers, bundle branches, AV node, AV bundle, SA nodeC. SA node, AV node, AV bundle, bundle branches, Purkinje fibersD. SA node, AV bundle, AV node, bundle branches, Purkinje fibersE. AV node, SA node, bundle branches, AV bundle, Purkinje fibers

C

Energy for contraction of myocardial cells comes primarily from

aerobic respiration in the mitochondria.

Which of the following will depolarize immediately after the AV node depolarizes?A. the AV bundleB. Purkinje fibersC. atrial myocardiumD. bundle branches in the ventricular septumE. the SA node

A

The action potentials are slowed at the AV node to allow theA. ventricles to repolarize.B. ventricles to completely empty of blood.C. pacemaker to reset for the next beat.D. atria to complete their contraction.E. atria to begin their contraction.

D

The plateau phase seen during the action potential of a cardiac muscle cell is due to the

continuing to have open calcium channels.

If the SA node is nonfunctional, which of the following is most likely to occur?A. The heart will go into asystole (stop).B. Tachycardia will develop.C. Another portion of the heart will become the pacemaker.D. The heart will go into defibrillation.E. The heart will be desensitized.

C

Calcium channel blockers are frequently used to

treat tachycardia or other arrhythmias.

When comparing cardiac muscle cells and skeletal muscle cells,A. the rate of action potential propagation is faster in cardiac muscle.B. both possess intercalated discs.C. only skeletal muscle has a plateau phase in its contraction cycle.D. action potentials are conducted from cell to cell only in cardiac muscle.E. both are voluntary.

D

Which of the following is mismatched?A. opening of sodium channels - depolarizationB. closing of calcium channels - plateau phaseC. opening of potassium channels - rapid repolarizationD. closure of sodium channels - early repolarizationE. opening of calcium channels - plateau phase

B

Which of the following areas of the conduction system would produce spontaneous action potentials most frequently if the SA node were not functioning?A. AV bundleB. Purkinje fibersC. AV nodeD. bundle branchE. the pacemaker

C

The period of time in which the myocardium is insensitive to further stimulation is called the

absolute refractory period

In a normal electrocardiogram, theA. P wave results from repolarization of the atria.B. QRS complex results from ventricular depolarization.C. P wave occurs after the QRS complex but before the T wave.D. T wave represents depolarization of the atria.E. repolarization of the atria is clearly visible.

B

Of the types of damage resulting from a myocardial infarction, which is most likely to cause the greatest increase in the Q-T interval?A. infarction in the AV nodeB. left bundle branch blockC. infarction affecting the SA nodeD. tachycardiaE. ectopic focus

B

What abnormal heart rhythm could be caused by an elevated body temperature, excessive sympathetic stimulation, or toxic conditions?

tachycardia

Variations in respiratory rate is a symptom ofA. sinus arrhythmia.B. ventricular tachycardia.C. SA node block.D. paroxysmal atrial tachycardia

A

. In the cardiac cycle,A. the right atrium and the right ventricle contract simultaneously.B. the two atria relax while the two ventricles contract.C. the left atrium contracts before the right atrium.D. all four chambers of the heart contract at the same time.E. all four chambers of the heart are in systole at the same time.

B

The period of isovolumetric contraction is immediately followed by

the period of ejection

Blood does not enter or leave the ventricles during the period called

isovolumetric contraction

Pressure in the right ventricle must exceed pressure in the ____ before the right ventricle can eject blood.

pulmonary trunk

The tricuspid valve is closed

during ejection

During the isovolumetric contraction period of the cardiac cycle,A. AV and semilunar valves are closed.B. the atria are contracted.C. ventricular volume increases.D. blood is pumped into the large arteries.E. pressure in the ventricles decreases.

A

What occurs during the time between the first heart sound and the second heart sound?

ventricular systole

The first and second heart sounds are most directly related to

vibrations that occur when the valves close

Regurgitation of blood flow through the aortic semilunar valve would give rise to

a heart murmur

The volume of blood pumped during each cardiac cycle is the

stroke volume

End-diastolic volume minus end-systolic volume is equal to

stroke volume

The dicrotic notch in the aortic pressure curve is due to the

backflow of blood toward the ventricles

Which of the following statements regarding intrinsic regulation of the heart is true?A. Stretching the SA node will decrease generation of action potentials in the node.B. Decreased venous return increases cardiac output.C. The heart's pumping effectiveness is greatly influenced by small changes in afterload.D. If cardiac muscle fibers are slightly stretched, they have a stronger contraction force.E. If cardiac muscle fibers are slightly stretched, they have a weaker contraction force.

D

The relationship between preload and stroke volume is known as

Starling Law of the heart

If the heart receives more sympathetic stimulation than parasympathetic stimulation, the heart will

increase its rate and force of contraction

Which of the following factors would cause an increase in heart rate?A. increased parasympathetic stimulationB. stimulation of baroreceptors in the aortaC. increased epinephrine release from the adrenal medullaD. increased production of atrial natriuretic factorE. vagal stimulation

C

Baroreceptor reflexesA. are triggered by increased blood osmolality.B. correct changes in blood pH.C. do not impact the activity of the heart.D. are of minor importance in humans.E. can change heart rate.

E

Which of the following will increase the heart rate?A. a rise in pHB. an increase in the level of carbon dioxide in the bloodC. an increase in the level of blood oxygenD. an increase in blood pressureE. a decrease in the level of carbon dioxide in the blood

B

Chemoreceptors sensitive to blood carbon dioxide levels are primarily located in the

medulla oblongata

An increase in extracellular calcium generally increases

the force of contraction.

Lowered extracellular potassium levels will lower the heart rate because

the resting membrane potential is hyperpolarized.

Aortic stenosis results from

a narrowed opening through the aortic valve