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Chapter 20

The space between the pleural cavities is called the ________.


In cardiac muscle

at least half of the calcium ion required for contraction comes from outside the cell.

At a heart rate of 60 beats/minute, a cardiac cycle lasts

1 second

Which of the following is greater during left ventricular systole?

the peak pressure in the ventricle

If there is a complete block between the SA node and the AV node, how would the ECG be affected?

The rate of P waves will be faster than the rate of QRS complexes.

The ________ separates the two atria.

interatrial septum

________ is the symptom generally brought on by coronary ischemia.

angina pectoris

The term ________ refers to blockage in the coronary circulation.

coronary artery disease

Oxygen is removed from blood as it flows through the ________ circuit.


Cardiac muscle cells and skeletal muscle cells differ in a few ways. Which of the following is not one of them?

Cardiac muscle cells lack transverse tubules.

Rupture of the papillary muscles in the left ventricle may result in

bicuspid regurgitation.
mitral regurgitation.
bicuspid prolapse.
mitral valve prolapse.

The wall of the left ventricle is thicker than the right because

both the left ventricle does more work than the right ventricle and the left ventricle produces a higher pressure than the right.

Blood returning to the heart from the pulmonary circuit first enters the

left atrium

Compared to the right ventricle, the left ventricle has all the following characteristics, except that it

pumps a greater volume

Tetanic muscle contractions don't occur in a normal cardiac muscle because

the refractory period lasts until the muscle relaxes.

What effect would compressing the inferior vena cava just below the diaphragm have on cardiac function?

Sympathetic stimulation of the heart would increase.

Artery is to ________ as vein is to ________.

efferent; afferent

Intercalated discs serve to transfer ________ from cell to cell.

the force of contraction
ionic currents
action potentials

The foramen ovale in the fetal heart is located in the

interatrial septum

Blood is supplied to the myocardium by

the coronary arteries.

Contractions of the papillary muscles

prevent the atrioventricular valves from reversing into the atria.

The inferior point of the heart is called the ________.


The pulmonary semilunar valve prevents backward flow into the

right ventricle

When the left ventricle contracts, the diameter of the ventricular chamber


Blood flowing into the heart from the venae cavae flows next through the ________ valve.


The circumflex branch and the anterior interventricular artery are branches of the

left coronary artery

The atrioventricular valves permit blood flow

in one direction only

In the middle of the thoracic cavity is a region occupied by the heart, great vessels, thymus, esophagus, and trachea called the


The right ventricle pumps blood to the

right and left lungs

The ________ valve prevents backward flow into the left atrium.


The left ventricle pumps blood to the


As blood leaves the right ventricle it passes through the ________ and then into the pulmonary trunk.

conus arteriosus

The pulmonary veins carry blood to the


The first blood vessels to branch from the aorta are the ________ arteries.


When the semilunar valves close, the AV valves then


The cusps (leaflets) of atrioventricular valves attach directly to

chordae tendineae

Most of the middle layer in the heart wall is composed of

cardiac myocytes

The bicuspid or mitral valve is located

between the left atrium and left ventricle.

The following is a list of vessels and structures that are associated with the heart.

1. right atrium
2. left atrium
3. right ventricle
4. left ventricle
5. venae cavae
6. aorta
7. pulmonary trunk
8. pulmonary veins

5, 1, 3, 7, 8, 2, 4, 6

The heart pumps approximately ________ liters of blood each day.


Blood returning to the heart from the systemic circuit first enters the

right atrium

The right atrium receives blood from the

coronary sinus, superior vena cava, and inferior vena cava.

The earlike extension of the atrium is the


The structure that permits blood flow from the right atrium to the left atrium in the fetal circulation is the

foramen ovale

The coronary sulcus is a groove that

marks the border between the atria and ventricles.

When the left ventricle contracts, the distance from the apex to the base


The ________ deliver(s) blood to the myocardium.

both right coronary artery and left coronary artery

Coronary veins empty into the

right atrium

The function of the atrium is to

both collect blood and pump blood to the ventricle.

Blood leaves the right ventricle by passing through the

pulmonary valve

The visceral pericardium is the same as the


The pulmonary arteries carry blood to the


The interventricular sulci and coronary sulcus contain

ateries, fat, veins

The heart is roughly the size of

a man's clenched fist

Which of the following descriptions matches the term near the left fifth intercostal space?


There are ________ pulmonary veins.


The marginal branch and posterior interventricular branch are branches of the

right coronary artery

The great and middle cardiac veins drain blood into the

coronary sinus

The term used to describe fluid collecting in the pericardial cavity that restricts the movement of the heart is known as

cardiac tamponade

The connective tissue fibers of the myocardium

help distribute the forces of contraction.
add strength and prevent overexpansion of the heart.
provide elasticity to help return the heart to its normal size.
provide physical support for cardiac muscle.

Blood is supplied to the left atrium by the

left coronary artery

Excess fluid in the ________ causes cardiac tamponade.

pericardial cavity

In order to perform a CABG, a cardiac surgeon must

both open the pericardial sac and visualize the visceral pericardium.

The heart lies within the ________.

pericardial cavity

The superior portion of the heart where major blood vessels enter and exit is the ________.


An equivalent term for epicardium is ________.

visceral pericardium

The wall of the ________ rests on the diaphragm.

right ventricle

The space between the pleural cavities is called the ________.


The ________ is shared by the two ventricles.

interventricular septum

Muscular ridges on the inner surface of the ventricles are called ________.

trabeculae carneae

The ________ circuit carries blood to and from the lungs.


The ________ circuit carries blood from the aorta to the right ventricle.


________ carry blood away from the heart.


________ carry blood toward the heart.


The ________ covers the outer surface of the heart.


The muscle layer of the heart is the ________.


The ________ lines the chambers of the heart, covers the heart valves, and is continuous with the endothelium.


Oxygen is added to blood as it flows through the ________ circuit.


In a procedure known as balloon ________, an inflatable balloon at the end of a catheter is used to press plaque back against the vessel wall.


A procedure in which a length of the patient's vein or artery is used to create a detour around an obstruction in a coronary artery is called ________.


A fine tubular wire mesh called a ________ may be inserted into a coronary vessel, holding it open.


As the left ventricle contracts, it bulges into the ________.

right ventricular cavity

The ________ is a remnant of an important fetal blood vessel that once linked the pulmonary and systemic circuits.

ligamentum arteriosum

The heart has four chambers, two small thin-walled ________ and two large muscular ________.

atria, ventricles

The long-term success rate of angioplasty greatly increases with the use of stents.


A slower-than-normal heart rate is called ________.


In cardiac muscle

at least half of the calcium ion required for contraction comes from outside the cell.

A faster-than-normal heart rate is called ________.


At a heart rate of 60 beats/minute, a cardiac cycle lasts

1 second

Which of these comparisons between skeletal and heart muscle is false?

both rely entirely on oxidative metabolism for energy.

Which of the following is greater during left ventricular systole?

the peak pressure in the ventricle

If there is a complete block between the SA node and the AV node, how would the ECG be affected?

The rate of P waves will be faster than the rate of QRS complexes.

If the connection between the SA node and AV node becomes blocked,

the ventricles will beat more slowly

The long plateau phase of the cardiac muscle action potential is due to

calcium channels remaining open

An increase in the rate of action potentials from baroreceptors will reflexly lead to

both decrease in heart rate and decrease in blood pressure.

During the T wave of the electrocardiogram, the ventricles are

both repolarizing and relaxing.

Depolarization of the atria corresponds to the EKG's

P wave

As a result of the long refractory period in the cardiac action potential, cardiac muscle cannot exhibit


The following are structural components of the conducting system of the heart.

1. Purkinje fibers
2. AV bundle
3. AV node
4. SA node
5. bundle branches

The sequence in which excitation would move through this system is

4, 3, 2, 5, 1

The normal pacemaker of the heart is located in the

SA node

The P wave of the electrocardiogram is a signal from

depolarization of the atria

The T wave on an ECG tracing represents

ventricular repolarization

Depolarization of the ventricles is represented on an electrocardiogram by the

QRS complex

Cardiac cells damaged by infarction will show which of the following?

release of troponin T and I into the circulation.
switch to anaerobic metabolism.
release of enzymes into the circulation.
release of MB-CK into the circulation.

Which part of the conduction system initiates the depolarizing impulse, which spreads throughout the heart?

SA node

What does the ECG wave tracing represent?

electrical activity in the heart

What does the QRS complex represent in the ECG wave tracing?

ventricular depolarization

Contraction of the atria results from which wave of depolarization on the ECG tracing?

P wave

Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles?

AV node

A heartbeat lasts

370 msec

If the pacemaker cells in the SA node become more permeable to potassium ions, the

both heart rate will decrease and membrane will hyperpolarize

Analysis of the electrocardiogram can reveal all of the following, except the

stroke volume

When a blood clot forms on a ruptured plaque in a coronary artery, the condition is referred to as a(n)

coronary thrombosis

AV nodal cells are poorly interconnected compared to contractile cells but they have bigger diameters.

The first part of the statement is true but the second part is false.

Abnormally slow depolarization of the ventricles would most change the shape of the ________ in an ECG tracing.

QRS complex

The property of heart muscle to contract in the absence of neural or hormonal stimulation is called ________.


Cells that spontaneously make action potentials make up ________ tissue.


The structures responsible for distributing excitation to the contractile cells are ________.

conducting fibers

The two types of cardiac muscle cells involved in a normal heartbeat include specialized cells of the ________ system and ________ cells.

conducting, contractile

A heart murmur might be caused by

aortic valve stenosis or mitral valve insufficiency or pulmonic valve insufficiency.

The relaxation phase of the cardiac cycle is called ________.


________ is when the heart can't maintain adequate cardiac output.

heart failure

As the heart rate slows, ________ gets longer.


If the connection between the vagus nerve and the heart is cut, which of these changes will occur?

NOT: (stroke volume will decrease, heart will beat slower, cardiac output will decrease, nodal fibers will depolarize more slowly )

During the isovolumetric phase of ventricular systole, the

atrioventricular valves and semilunar valves are closed.

The one-way nature of the left AV valve prevents blood flow from _________.

the left ventricle to the left atrium

The closing of the left AV valve occurs near the beginning of __________.

ventricular systole

The majority of ventricular filling occurs while the ventricles and atria are in what state(s)?

ventricular and atrial diastole

Which of the following most correctly describes end-diastolic volume?

the volume of the ventricle when it is most full

Left ventricular filling occurs __________.

while the AV valve is open

Heart valves are in what state during isovolumetric contraction?

The AV valves and semilunar valves are closed.

The decrease in left ventricular pressure at the end of ventricular systole causes __________.

the semilunar valve to close

Ventricular diastole begins with the closing of the semilunar valves. What phase of the cardiac cycle happens between this event and the later opening of the AV valves?

isovolumetric relaxation

The contraction phase of the cardiac cycle is called ________.


Compared to the right ventricle, which of these statements about the left ventricle is false?

it ejects more blood

The first heart sound is heard when the

AV valves close.

During the cardiac cycle, the

both QRS complex of the ECG precedes the increase in ventricular pressure and first heart sound coincides with the QRS complex of the ECG.

Isovolumetric relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________.

ventricular diastole

Which of the following is correct about the filling of the ventricles?

Most blood flows passively into the ventricles through open AV valves.

Describe the pressures in the atria and ventricles that would cause the opening of the AV valves.

Pressure in the atria would be greater than the pressure in the ventricles.

What causes the aortic semilunar valve to close?

greater pressure in the aorta than in the left ventricle

Put the phases of the cardiac cycle in the correct order, starting after ventricular filling.

isovolumetric contraction, ventricular ejection, isovolumetric relaxation

Increased pressure in the ventricles would close what valve(s)?

AV valves only

________ are abnormal heart sounds caused by turbulent flow through faulty valves.


The backward flow of blood from a ventricle to its atrium or from a outflow vessel to its ventricle is called ________.


Which of the following would increase heart rate?

decreased parasympathetic stimulation of nodal fibers
increased levels of epinephrine
increased sympathetic stimulation of SA node
faster depolarization of the pacemaker potential

Each of the following factors will increase cardiac output, except

increased parasympathetic stimulation.

Cardiac output is increased by

more sympathetic stimulation and increased stroke volume.

The cardiac ________ is the difference between the resting and maximal cardiac output.


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