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chapter 14
HEART
The structure of the heart allows it to serve as two distinct pumps. One side of the heart pumps blood to the lungs
while the other side propels oxygenated blood throughout the body. The heart is unique in other ways as well. For
example, it consists of muscle found nowhere else in the body. What’s more, cardiac cells can generate and
transmit electrical impulses spontaneously. Learn more about the characteristics of this vital organ by completing
the activities in this chapter.

Conceptualize in Color: Heart Layers

Test your knowledge of the layers of the heart’s wall and the pericardium by coloring the figure as suggested.

● Endocardium: Light pink ● Serous pericardium: Light blue

● Myocardium: Dark pink ● Place green Xs in the pericardial space.
● Fibrous pericardium: Orange ● Draw a bracket linking the layers that make up the
serous pericardium.

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Puzzle It Out: Cardiac Terms

Complete the following crossword puzzle to test your knowledge of terms used in the study of the heart.

ACROSS DOWN
1. The heart’s inner layer 2. Unique ability of the cardiac muscle to contract
4. The study of the heart and the treatment of without nervous stimulation
related disorders 3. Where the great vessels enter and leave the heart
5. Thin layer of squamous epithelial cells covering 6. Double-walled sac surrounding the heart and root
the heart’s surface of the great vessels
7. Space between the lungs and beneath the sternum 8. The period of cardiac muscle relaxation
where the heart resides 11. Two upper chambers of the heart
9. Pointed end of the heart
10. Two lower chambers of the heart
12. Phase of the cardiac cycle when the ventricles
contract
13. Heart’s middle layer

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Drawing Conclusions: Heart Structures

Color the heart structures in the following figure; use the colors suggested or choose your own. Then identify each
of the heart’s four valves (noted by the letters A through D in the figure) and describe the function of each; use the
spaces provided.

● Right atrium: Dark blue ● Interatrial septum: Orange

● Right ventricle: Light blue ● Interventricular septum: Yellow
● Left atrium: Light red ● Tendinous cords (chordae tendineae): Black
● Left ventricle: Dark red ● Papillary muscle: Brown

Heart valves and functions:

A.
B.
C.
D.

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Illuminate the Truth: Heart Valves

Highlight the correct word or phrase in each of the following sentences.

1. (Nerve impulses) (Pressure changes within the heart) trigger the opening and closing of the heart’s valves.
2. A heart valve that fails to prevent the backflow of blood during contraction is called (incompetent) (stenotic),
and the condition it causes is called valvular insufficiency.
3. (Valvular stenosis) (Regurgitation) is a condition resulting when a heart valve becomes narrowed, such as from
scar tissue.
4. The mitral valve consists of (three) (two) cusps or leaflets.
5. The pulmonary and aortic valves are also called (semilunar) (tricuspid) valves.
6. The valves regulating flow between the atria and the ventricles are called (atrioventricular) (semilunar) valves.
7. The semi-rigid, fibrous connective tissue encircling each valve is called the (skeleton) (epicardium) of the heart.
8. Tendinous cords called chordae tendineae work to (pull the valves open when the heart contracts) (keep the
tricuspid valve from inverting during ventricular contraction).

Drawing Conclusions: Heart Sounds

When heart valves close, they produce vibrations that can be heard with a stethoscope on the body’s surface. In the
following figure, identify the areas where each valve can be heard by coloring the circles as suggested; then fill in the
name of each valve.
● Pulmonic area: Blue ● Mitral area: Yellow ● Tricuspid area: Green ● Aortic area: Orange

1 2

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Sequence of Events: Blood Flow Through the Heart

Test your knowledge of the flow of blood through the heart by placing the following cardiac events in the proper
order. The first step has been provided to get you started. Arrange the subsequent events by inserting the numbers
2 through 18 in the spaces provided.

1. Deoxygenated blood flows through the superior and inferior vena cava and into the right atrium.

A. Blood fills the left atrium.

B. The right atrium contracts.
C. The pulmonary valve closes.
D. Blood leaves the lungs via the pulmonary veins.
E. The left atrium contracts.
F. The pulmonary valve opens.
G. Blood flows into the aorta for distribution throughout the body.
H. The mitral valve closes.
I. The left ventricle contracts.
J. The aortic valve opens.
K. The right ventricle contracts.
L. The tricuspid valve opens.
M. Blood is pumped into the right and left pulmonary arteries and into the lungs.
N. Blood fills the left ventricle.
O. The mitral valve opens.
P. Blood flows into the right ventricle.
Q. The tricuspid valve snaps closed.

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Fill in the Gaps: Coronary Circulation

Fill in the blanks to complete the sentences. Choose from the words provided in the Word Bank. (Hint: Not all the
words will be used.)

ANTERIOR DESCENDING CORONARY SINUS RELAXATION

ASCENDING AORTA INTERVENTRICULAR SEPTUM RIGHT
CIRCUMFLEX LEFT SUPERIOR VENA CAVA
CONTRACTION LEFT VENTRICLE

1. The right and left coronary arteries arise from the .

2. The coronary artery supplies blood to the right atrium, part of the left atrium,
most of the right ventricle, and the inferior part of the left ventricle.

3. The left coronary artery branches into the and

arteries.

4. The left coronary artery supplies blood to the left atrium, most of the left ventricle, and most of the
.

5. Most cardiac veins empty into the , a large transverse vein on the heart’s posterior,
which returns blood to the right atrium.

6. The coronary arteries receive their supply of blood during ventricular .

7. The most abundant blood supply goes to the myocardium of the .

List for Learning: Pacemakers of the Heart

List the heart’s three possible pacemakers (the primary pacemaker as well as the “backup” pacemakers) along with
their firing rates.

1.
2.
3.

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Drawing Conclusions: Cardiac Conduction System

In the following illustration, color and then label the structures of the cardiac conduction system. Use the colors
suggested or choose your own.

● SA node: Red ● Purkinje fibers: Pink

● AV node: Green ● Interatrial tracts: Brown
● Bundle of His: Purple ● Internodal tracts: Orange
● Right and left bundle branches: Blue

Next, indicate the conduction pathway by placing a number by each of the labels, beginning by placing the number
1 by the name of the structure where the impulse begins and the number 7 by the structure where the impulse ends.

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Describe the Process: Cardiac Cycle

The following illustrations show the five events of the cardiac cycle. Identify each event by filling in the blanks
below each figure. Circle the name of the event when the first heart sound can be heard. Underline the name
of the event when the second heart sound can be heard.

1 2 3 4 5

1.

2.

3.

4.

5.

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Fill in the Gaps: Cardiac Output

Place one word in each blank line to complete the following sentences. Choose from the words listed in the Word
Bank. (Hint: Not all the words will be used; also, one word will be used more than once.)

CARDIAC OUTPUT FIVE PARASYMPATHETIC SYMPATHETIC

DECREASES HEART RATE SIX TEN
EIGHT INCREASES STROKE VOLUME

1. The amount of blood ejected with each heartbeat is called .

2. The amount of blood the heart pumps in 1 minute is called .

3. To determine cardiac output, you would multiply by

.

4. The average resting cardiac output is between and

liters per minute.

5. When heart rate increases, cardiac output .

6. The nervous system can cause the heart rate to increase by sending impulses via the
nervous system.

7. The nervous system sends signals to slow the heart rate.

Illuminate the Truth: Stroke Volume

Highlight the correct word in each of the following sentences.

1. (Preload)(Afterload) is the amount of tension, or stretch, in the ventricular muscle just before it contracts.
2. (Contractility)(Stroke volume) is the force with which ventricular ejection occurs.
3. Starling’s law of the heart states that the more the ventricle is stretched—within limits—the (less)(more)
forcefully it will contract.
4. The force against which the heart must work to eject its volume of blood is called the (cardiac
output)(afterload).
5. Factors that affect contractility are called (chronotropic)(inotropic) agents.
6. Factors that affect heart rate are called (diastolic)(chronotropic) agents.

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Puzzle It Out: More Heart Facts

Hone your knowledge of the heart by completing the following crossword puzzle.

ACROSS DOWN
4. A persistent pulse rate slower than 60 beats 1. A persistent, resting heart rate greater than
per minute 100 beats per minute
6. An ECG that appears normal is called normal 2. Pressure sensors in the aorta and internal carotid
rhythm. arteries that detect changes in blood pressure
7. Pacemakers other than the SA node are called this 3. The right and left ventricles receive 70% of their
9. An irregular heartbeat blood .
10. The ventricle with the thickest walls 5. Results from an interruption of blood to the
12. Pooling of fluid in the abdomen myocardium
13. The blood remaining in the ventricles at the end of 8. Cell death
the ejection period is the 11. Heart sound that results from turbulent blood
volume. flow through a stenotic valve
14. The gender most likely to die from a first heart
attack

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