The Cardiovascular System25
C A S E
S T U D Y
PATIENT INFORMATION
Patient Name
DOB
John Miller
12/5/19XX Bee stings
Attending
MRN
Other Information
082-09981
Current Medications: Glyburide 2.5
mg daily, Captopril 25 mg bid, HCTZ
25 mg daily
Paul F.
Buckwalter,
MD
Allergies
© McGraw-Hill Education
John Miller, a 65-year-old patient, was referred to the cardiologist’s office for
an evaluation. The patient has a history of hypertension and had a
myocardial infarction (heart attack) 4 years ago. More recently, he was
diagnosed with mild congestive heart failure (CHF). Three weeks ago, on the
advice of his primary care physician, he started a light exercise program for
weight loss. Following exercise he has had a radiating chest pain (angina
pectoris) that stopped after rest.
The condition has worsened in the last week. The cardiologist ordered a
stress echocardiogram (a test that visualizes the heart during increasing
stress). The stress echocardiogram results suggested that the chest pain
may be due to coronary artery disease (CAD). The patient was scheduled for
a cardiac catheterization the next morning. It was noted in the patient’s
chart that he smokes two packs of cigarettes per day.
Keep John in mind as you study this chapter. There will be questions at the end of the chapter
based on the case study. The information in the chapter will help you answer these questions.
L E A R N I N G
O U T C O M E S
After completing Chapter 25, you will be able to:
1. 25.1Describe the structures of the heart and the function of each.
2. 25.2Explain the cardiac cycle, including the cardiac conduction system.
3. 25.3Differentiate among the different types of blood vessels and their
functions.
4. 25.4Compare the various types of circulation.
5. 25.5Explain blood pressure and tell how it is controlled.
6. 25.6Describe the causes, signs and symptoms, and treatments of various
diseases and disorders of the cardiovascular system.
K E Y T E R M S
1. atrioventricular node (AV node)
2. bundle of His
3. cardiac output
4. chordae tendineae
5. coronary circulation
6. diastolic pressure
7. embolus
8. endocardium
9. epicardium
10.
hepatic portal system
11.
myocardium
12.
pericardium
13.
pulmonary circulation
14.
Purkinje fibers
15.
sinoatrial node (SAs node)
16.
stenosis
17.
systemic circulation
18.
systolic pressure
19.
vasoconstriction
20.
vasodilation
21.
viscosity
Page 541
M E D I C A L
CAAHEP
A S S I S T I N G
C O M P E T E N C I E S
1. I.C.4
List major organs in each body system
2. I.C.5
Identify the anatomical location of major organs in each body system
3. I.C.7
Describe the normal function of each body system
4. I.C.8
Identify common pathology related to each bodysystem including
(a) signs
(b) symptoms
(c) etiology
5. I.C.9
Analyze pathology for each body system including:
(a) diagnostic measures
(b) treatment modalities
6. V.C.9
Identify medical terms labeling the word parts
7. V.C.10
Define medical terms and abbreviations related to all body systems
ABHES
2. Anatomy & Physiology
a. List all body systems, their structure and functions
b. Describe common diseases, symptoms, and etiologies as they
apply to each system
c. Identify diagnostic and treatment modalities as they relate to
each system
3. Medical Terminology
a. Define and use entire basic structure of medical words and be able
to accurately identify in the correct context, i.e. root, prefix, suffix,
combinations, spelling, and definitions
b. Build and dissect medical terms from roots/suffixes to understand
the word element combinations that create medical terminology
c. Apply various medical terms for each specialty
d. Define and use medical abbreviations when appropriate and
acceptable
4.
Introduction
5. The cardiovascular system consists of the heart and blood vessels. It pumps blood
to the lungs to pick up oxygen and to the digestive system to pick up nutrients. It
then delivers the oxygen and nutrients to all of the body cells. At the same time, it
picks up waste products from the body cells and transports them to the lungs,
kidneys, and other organs for removal from the body.
The Heart
LO 25.1
The heart is a cone-shaped organ about the size of a loose fist. It is located within the
mediastinum (central part of the chest) and extends from the level of the second rib to
about the level of the sixth rib. Although many people think the heart is in the left side of
the chest, it is located only slightly left of the midline of the body. The heart is bordered
laterally by the lungs, posteriorly by the vertebral column, and anteriorly by the
sternum. Inferiorly, the heart rests on the diaphragm.
Cardiac Membranes
The heart is enclosed by a membrane called the pericardium, or pericardial sac
(see Figure 25-1). The pericardium has two parts. The outer part, called the fibrous
pericardium, consists of a tough, fibrous material that helps protect the heart and anchor
it in the chest. The inner part of the pericardium, which is called the serous
pericardium, has two layers: the parietal pericardium and the visceral pericardium. The
visceral pericardium is actually the outermost layer of the heart. The area between these
two layers of the pericardium is known as the pericardial cavity. It contains pericardial
fluid, which reduces the friction between the membranes when the heart contracts and
relaxes.
FIGURE 25-1 Location and membranes of the heart.
The Heart Wall
The wall of the heart (see Figure 25-2) is composed of the following three layers:
 Epicardium. This outermost layer is the visceral pericardium. It contains fat, which
helps to cushion the heart.
 Myocardium. This middle layer is the thickest layer of the wall and is made primarily
of cardiac muscle.
 Endocardium. This innermost layer is thin and very smooth. This layer contains part
of the cardiac electrical conduction system, which is discussed later in this chapter.
FIGURE 25-2 Layers of the wall of the heart.
Heart Chambers and Valves
The heart contains four hollow chambers, two on the left and two on the right
(see Figure 25-3). The upper chambers of the heart are called atria (the singular form
is atrium). They have thin walls and receive blood returning to the heart from the lungs
and the body. The bottom chambers of the heart are the ventricles. The ventricles pump
blood into the arteries, which send the blood to the lungs and the body. The wall that
separates the left and right sides of the heart is the septum.
FIGURE 25-3 The chambers and valves of the heart are visible in this coronal section.
For the heart to function properly, the blood must move through it in only one direction.
The four valves within the heart that keep blood flowing in one direction are the
tricuspid and the bicuspid (mitral) valves, which are located Page 542between the atria
and ventricles, and the pulmonary semilunar and aortic semilunar valves, which are
located between the ventricles and their arteries.
Tricuspid Valve The tricuspid valve has three cusps and is located between the right
atrium and the right ventricle (see Figure 25-4). It prevents blood from flowing back into
the right atrium when the right ventricle contracts. This valve is also called the right
atrioventricular (AV) valve. The cusps of this valve are anchored by cord-like structures
called chordae tendineae to bumps of cardiac muscle calledpapillary muscles. These
muscles contract when the ventricles contract, closing the valve.
FIGURE 25-4 Valves viewed
from a cross section of the heart.
Bicuspid Valve The bicuspid valve has two cusps and is located between the left atrium
and the left ventricle. It prevents blood from flowing back into the left atrium when the
left ventricle contracts. This valve is also known as the mitral valve and the left AV
valve. Like the tricuspid valve, the bicuspid valve also has chordae tendineae attached to
papillary muscles.
Pulmonary Semilunar Valve The pulmonary semilunar valve is located between the right
ventricle and the trunk of the pulmonary arteries. It prevents blood from flowing back
into the right ventricle. Because its cusps are shaped like a half moon, this valve is called
a semilunar valve.
Page 543 Aortic Semilunar Valve The aortic semilunar valve is between the left ventricle
and the aorta. It prevents blood from flowing back into the left ventricle and is also a
semilunar valve.
Cardiac Cycle
LO 25.2
One heartbeat makes up one cardiac cycle. During the course of one cardiac cycle, all
four heart chambers contract and then relax. The atria contract first, then the ventricles.
Here are the actions that occur:
 Right atrium contracts → tricuspid valve opens → blood flows into the right ventricle.
 Left atrium contracts → bicuspid valve opens → blood flows into the left ventricle.
 Right ventricle contracts → tricuspid valve closes, pulmonary semilunar valve opens
→ blood is pushed into the trunk of the pulmonary artery.
 Left ventricle contracts → bicuspid valve closes, aortic semilunar valve opens → blood
is pushed into the aorta.
The following factors influence the cardiac cycle:
 Exercise. Strenuous exercise increases the heart rate because skeletal muscles need
more oxygen.






Parasympathetic nerves. The parasympathetic nerve to the heart is the vagus nerve,
and it generally keeps the heart rate relatively low.
Sympathetic nerves. The sympathetic nerves increase the heart rate during times of
stress. Parasympathetic and sympathetic nerves are discussed in more detail in The
Nervous System chapter.
Cardiac control center. This center is located in the medulla oblongata, which is part
of the brainstem. When blood pressure rises, this control center sends impulses to
decrease the heart rate. When blood pressure falls, it sends impulses to increase the
heart rate.
Body temperature. An increase in body temperature usually increases the heart rate.
This explains the high heart rate when a person runs a fever.
Page 544Potassium ions. A low concentration of potassium ions in the blood decreases
the heart rate, but a high concentration causes a dysrhythmia (abnormal heart rate).
Calcium ions. A low concentration of calcium ions in the blood depresses heart
actions, but a high concentration causes heart contractions called tetanic
contractions, which are longer than normal heart contractions.
Cardiac Cycle
Heart Sounds
During one cardiac cycle, you can hear two heart sounds. The sounds, commonly
called lubb and dubb, are generated when valves in the heart snap shut. Lubb is the first
heart sound and occurs when the ventricles contract and the tricuspid and bicuspid
valves snap shut. Dubb is the second heart sound and occurs when the atria contract
and the pulmonary and aortic semilunar valves snap shut.
Physicians listen to heart sounds to diagnose certain conditions. For example, if an AV
valve (tricuspid or bicuspid) is damaged, it will not close completely. This allows blood
to leak back into the atria when the ventricles contract and produces an abnormal heart
sound called amurmur. Murmurs may indicate serious heart conditions, although many
heart murmurs are harmless.
Cardiac Conduction System
The cardiac conduction system consists of a group of structures that send electrical
impulses through the heart. When cardiac muscle receives an electrical impulse, it
contracts (see Figure 25-5). The components of the cardiac conduction system are the
sinoatrial node, atrioventricular node, bundle of His, and Purkinje fibers.
FIGURE 25-5 In the cardiac conduction system, impulses begin at the sinoatrial (SA) node and
travel through the heart in the order shown here.
Sinoatrial node (SA node). This node is located in the wall of the right atrium and
generates an impulse that flows to the atrioventricular node. The SA node is also
known as the natural pacemaker of the heart because it generates the heart’s rhythmic
contractions.
 Atrioventricular node (AV node). This node is located between the atria, just above the
ventricles. After the impulse reaches the AV node, the atria contract and the impulse
is sent to the bundle of His.
 Bundle of His. This structure, also known as the atrioventricular, or AV, bundle, is
located between the ventricles and splits into two branches, forming the left and
right bundle branches, before sending the electrical impulse to the Purkinje fibers.
 Purkinje fibers. These fibers are located in the walls of the ventricles. As the impulse
flows through the Purkinje fibers, it causes the ventricles to contract.
Physicians use a test called an electrocardiogram (ECG or EKG) to tell if the cardiac
conduction system is working properly. In a normal ECG, the waves shown in Figure 256 are produced. The first wave (P wave) indicates that an electrical impulse was sent
through the atria, causing them to contract (depolarization). The Q, R, and S waves
occur together and make up the QRS complex. This complex indicates that an electrical
impulse was sent through the ventricles, causing them to contract (depolarization).

Finally, the T wave indicates electrical changes that occur in the ventricles as they Page
545 relax (repolarization). You will learn more about the electrical conduction system of
the heart and ECGs, including how to perform them, in the chapter Electrocardiography
and Pulmonary Function Testing.
FIGURE 25-6 Electrocardiogram: (a) a normal ECG
Blood Vessels
LO 25.3
Blood circulation takes place in blood vessels that form a closed pathway to carry blood
from the heart to cells and back again. These vessels include arteries, arterioles, veins,
venules, and capillaries.
Arteries and Arterioles
Arteries carry blood away from the heart and are the strongest of the blood vessels. They
have a thick layer of smooth muscle that can withstand the high pressure the heart
exerts on them (see Figure 25-7). This pressure is necessary to carry the blood
throughout the body. Small branches of arteries are called arterioles.
FIGURE 25-7 Arteries have much thicker walls than other blood vessels. (left) Cross section of
an artery. (right) Cross section of a vein.© Microscape/SPL/Science Source
The largest artery in the body is the aorta, which receives its blood directly from the left
ventricle. The aorta branches into the coronary arteries and many other major arteries
that supply blood to various parts of the body. Major arteries are summarized in Table
25-1 and illustrated in Figure 25-8. Many arteries are paired, meaning there is a left and
a right artery of the same name.
TABLE 25-1 Major Arteries of the Body
Artery
Anatomical Location or Organ Supplied
Lingual
Tongue
Facial
Face
Occipital
Back of scalp and neck
Maxillary
Teeth, jaw, and eyelids
Ophthalmic
Eye
Axillary
Armpit area
Brachial
Upper arm
Ulnar
Forearm and hand
Radial
Forearm and hand
Intercostals
Rib area
Lumbar
Posterior abdominal wall
External iliac
Anterior abdominal wall
Common iliac Legs, gluteal area, and pelvic organs
Femoral
Thigh
Popliteal
Posterior knee
Tibial
Lower leg and foot
FIGURE 25-8
Major arteries of the body (a. stands for artery).
Page 546
Most arteries carry oxygenated blood. The exceptions to this are the pulmonary arteries,
which carry deoxygenated blood from the heart to the lungs.
Capillaries
Capillaries are the smallest type of blood vessel. They branch off of arterioles and have
walls that are only about one cell layer thick. These thin walls make the exchange of
oxygen, carbon dioxide, and nutrients possible between the blood and the body cells
(see Figure 25-9). In fact, capillaries are the only type of blood vessels that allow
substances to move into and out of the blood. Tissues that require a lot of oxygen, such
as muscle and nervous tissues, have a lot of capillaries.
FIGURE 25-9
Structure of a capillary wall.
The substances that move through the capillary walls include oxygen, carbon dioxide,
nutrients, water, and metabolic wastes. These substances move through the walls
through one of three processes: diffusion, filtration, or osmosis. These processes are
described in the Organization of the Body chapter.
Veins and Venules
Veins are blood vessels that carry blood toward the heart. Unlike arteries, they are not
under high pressure, so they do not need thick, muscular walls. Their walls are thinner
than those of arteries. Because the blood in veins is not under pressure, veins have
valves that prevent backflow and keep the blood moving toward the heart (see Figure 2510).
FIGURE 25-10 Venous valve: (a) valve opens when blood is flowing toward the heart and (b)
valve closes to prevent blood from flowing away from the heart.
Page 547
EDUCATING THE PATIENT
Chest Pain
Chest pain, or angina, is a common reason for people to go to the
emergency room or an urgent care center. Explain to patients that there are
many causes of chest pain, both cardiac and noncardiac. Cardiac causes
include myocardial infarction (MI, or heart attack), pericarditis, and coronary
spasms. See the Pathophysiology section of this chapter for more detailed
descriptions of these causes. Noncardiac causes include heart-burn, panic
attacks, lung conditions, broken ribs, inflammation of the gallbladder or
pancreas, and even just sore muscles. However, tell patients that all chest
pain should be taken seriously, because some conditions, both cardiac and
noncardiac, can be life-threatening if not treated.
Skeletal muscle contractions help move the blood through veins. When the muscles
contract, they squeeze the veins and blood is pushed through them, much the way
toothpaste is pushed out of a tube. The sympathetic nervous system also influences the
flow of blood through veins. If blood pressure becomes abnormally low, the sympathetic
nervous system causes vein walls to constrict, which forces blood through the veins.
Venules are very small veins formed when capillaries merge together (see Figure 25-11).
The venules then merge to form the veins.
FIGURE 25-11 This light micrograph of a
capillary network shows the capillaries merging to become venules. © Biophoto Associates/Science
Source
Most veins carry deoxygenated blood. The exceptions to this are the pulmonary veins,
which carry oxygenated blood from the lungs to the left ventricle of the heart. Large
veins often have the same names as the arteries they run next to, but there are
exceptions. For example, the veins next to the carotid arteries are the jugular veins.
Large veins empty blood into the superior vena cava and the inferior vena cava
(plural: venae cavae), which are the largest veins in the body. The superior vena cava
generally collects blood from veins above the heart, and the inferior vena cava collects
blood from veins below the heart. The major veins are summarized in Table 25-2 and are
illustrated in Figure 25-12.
TABLE 25-2 Major Veins of the Body
Vein
Anatomical Location or Organ Drained
Jugular
Head and neck
Brachiocephalic Head and neck
Axillary
Armpit area
Brachial
Upper arm
Ulnar
Lower arm and hand
Radial
Lower arm and hand
Intercostal
Rib area
Azygos
Thorax and abdomen
Iliac
Pelvic organs, legs, and gluteal areas
Femoral
Thighs
Popliteal
Knees
Saphenous
Legs
Hepatic
Liver to the inferior vena cava
Hepatic Portal System
Gastric
Stomach to the liver
Splenic
Spleen, pancreas, and stomach to the liver
Mesenteric
Intestines to the liver
Hepatic portal
Gastric, splenic, and mesenteric veins to the liver
FIGURE 25-12 Major veins of the body (v.
stands for vein).
The veins of the intestines carry blood from the digestive tract to the liver. The liver then
processes nutrients in the blood and returns it to general circulation through the hepatic
veins. The veins involved in this process are known as the hepatic portal system
Circulation
LO 25.4
Blood circulates through the body through three main circuits. The pulmonary
circuit provides oxygen, the systemic circuit distributes the oxygen throughout the body,
and the coronary circuit distributes the oxygen to the heart muscle.
Pulmonary Circulation
The pulmonary circuit, or pulmonary circulation, is the route blood takes from the heart
to the lungs and back to the heart again (seeFigure 25-13). The purpose of this circuit is
to remove waste gases such as carbon dioxide and replenish the blood with oxygen.
When blood returns to the heart from the body cells, it is low in oxygen (deoxygenated)
and rich in carbon dioxide. As described earlier in this chapter, the deoxygenated blood
enters the right atrium, which delivers it to the right ventricle. The right ventricle pumps
the blood through the left and right pulmonary arteries to the lungs.
FIGURE 25-13 Pathway of blood through the heart and lungs and on to other body parts. The
right side of the heart delivers blood to the lungs (pulmonary circulation), and the left side
delivers blood to all other body parts (systemic circulation).
In the lungs, blood picks up oxygen and gets rid of carbon dioxide. Blood rich in oxygen
and low in carbon dioxide then returns to the heart through the four pulmonary veins.
The pulmonary veins empty the oxygenated blood into the left atrium.
Page 549
Systemic Circulation
The systemic circuit, or systemic circulation, is the route blood takes from the heart
through the body and back to the heart. The purpose of this circuit is to deliver oxygen
and nutrients to the body cells. It also picks up carbon dioxide and waste products from
the body cells (seeFigure 25-13).
Blood that returns from the lungs and enters the left atrium is oxygen rich (oxygenated)
and has a low level of carbon dioxide. It flows from the left atrium to the left ventricle,
which contracts to pump the oxygenated blood into the aorta, which branches off to
various arteries to deliver the blood throughout the body.
The arteries branch into the smaller arterioles, and the arterioles branch into capillaries.
In the capillaries, oxygen and nutrients picked up from the digestive system move from
the blood into the body cells. Carbon dioxide and metabolic wastes move from the body
cells into the blood. The blood then moves through the venules and veins and is
collected into the vena cava, which delivers the blood back to the right atrium of the
heart, and the whole process starts over again with pulmonary circulation.
Coronary Circulation
Coronary circulation is the part of systemic circulation that supplies oxygen and
nutrients to the heart and removes carbon dioxide and other wastes. The coronary
arteries branch directly off the aorta immediately after the blood leaves the left atrium
(see Figure 25-14). Like all other arteries, the coronary arteries branch into smaller and
smaller vessels, ending in capillaries, where oxygen and nutrients move into the heart
cells and carbon dioxide and wastes move into the blood. The blood then travels through
the venules and the cardiac veins, which merge to form a large vein called the coronary
sinus. Unlike other veins, however, the coronary sinus does not empty into the vena cava.
It empties directly into the right atrium.
FIGURE 25-14 Coronary circulation. (a) The coronary arteries and their branches supply blood
to the heart muscle. (b) The cardiac (coronary) veins collect the deoxygenated blood and deposit
it into the coronary sinus, which empties into the right atrium.
Blockage of one or more of the coronary arteries may cause chest pain, or angina, and
may lead to myocardial infarction (MI, or heart attack) if not corrected. See
the Educating the Patient feature and the Pathophysiology section of this chapter for
more information about these disorders.
Blood Pressure
LO 25.5
Blood pressure is the force that blood exerts on the inner walls of blood vessels. Blood
pressure is highest in arteries and lowest in veins. In the clinical setting, blood
pressure refers to the pressure in arteries.
Arterial blood pressure rises and falls as the ventricles of the heart contract and relax. It
is highest when the ventricles contract. This highest point of pressure is called
the systolic pressure or systole. When the ventricles relax, blood pressure in arteries is at
its lowest. This pressure is called the diastolic pressure or diastole. Blood pressure is
usually reported as the systolic pressure over the diastolic pressure. For example, in the
blood pressure reading 120/80, 120 denotes the systolic pressure and 80 refers to the
diastolic pressure.
You can feel the surge of blood through arteries when you take a pulse. The pulse is
created as the artery expands when pressure increases and then subsequently relaxes as
blood pressure decreases. Common places to feel a pulse are the carotid and radial
arteries.
Many factors affect blood pressure, including cardiac output, blood volume,
vasoconstriction, vasodilation, and blood viscosity. Cardiac output is the total amount of
blood the heart pumps in 1 minute. As cardiac output increases, it causes an increase in
blood pressure. When cardiac output decreases, blood pressure decreases accordingly.
When a person loses a large volume of blood, his blood pressure significantly decreases.
If the blood pressure falls too low, the muscular walls of the arteries can constrict to
increase blood pressure. This process is known as vasoconstriction. If a person’s blood
pressure is too high, the blood vessels dilate, decreasing the blood pressure. This process
is known as vasodilation.
The viscosity, or thickness, of blood also plays a part in blood pressure. Under certain
circumstances, such as dehydration, the blood becomes more viscous, or thicker. The
thicker blood requires more energy to move and results in higher blood pressure.
Blood pressure is controlled to a large extent by the amount of blood pumped out of the
heart. The amount of blood entering the heart should be equal to the amount of blood
pumped out of the heart. The heart has a way to ensure that this happens. When blood
enters the left ventricle, the wall of the ventricle is stretched. The more the wall is
stretched, the harder it will contract and the more blood it will pump out. This is
referred to as Starling’s law of the heart. If only a small amount Page 550Page 551of blood
enters the left ventricle, it will not be stretched very much and therefore will not
contract very forcefully. In this case, not much blood is pumped out of the heart.
Baroreceptors also help regulate blood pressure. Barore-ceptors measure blood pressure
and are located in the aorta and carotid arteries. If pressure increases in these blood
vessels, this information is sent to the cardiac center in the medulla oblongata. The
cardiac center then knows to decrease the heart rate, which lowers blood pressure. If
pressure gets too low in the aorta, baroreceptors pick up this information and relay it to
the cardiac center. The cardiac center then increases the heart rate to raise blood
pressure.
PATHOPHYSIOLOGY
LO 25.6
Common Diseases and Disorders of the Cardiovascular System
HYPERTENSION, or high blood pressure, is a consistent resting blood
pressure of 140/90 mm Hg or higher. It is known as the “silent killer,”
because it increases a person’s risk of heart attack, stroke, heart failure, and
kidney failure, sometimes without presenting symptoms that could warn the
person of medical risk. The American Heart Association estimates that 73
million American adults have hypertension, with African Americans having a
higher incidence than Caucasians.
Causes. Known causes and risk factors for hypertension include narrowing of
the arteries, kidney disease, endocrine disorders, pregnancy, drug use
(especially cocaine and amphetamines), sleep apnea, obesity, smoking, a
high-sodium diet, excessive alcohol consumption, stress, diabetes, and
various medications such as oral contraceptives and cold medicines.
However, many of the causes of hypertension are unknown.
Signs and Symptoms. Hypertension often causes no symptoms at all. When
symptoms are present, they include excessive sweating, muscle cramps,
fatigue, frequent urination, headaches, dizziness, and an irregular heart
rate.
Treatment. Hypertension cannot be cured, but it can be controlled. The first
method of treatment is to treat the underlying causes, if they are known. For
example, the patient may be placed on a low-sodium/low-cholesterol diet
and may be encouraged to make lifestyle changes such as getting regular
exercise, managing stress, and stopping smoking. The physician may also
prescribe medications to slow the heart rate and/or dilate the blood vessels
and diuretics to reduce blood volume.
Patient compliance is the key to successful management of hypertension.
Because hypertension often has no symptoms, but the prescribed
medications may have noticeable side effects, patients may stop taking the
medications because they feel better when they do not take it. Be sure
patients understand that taking the medication(s) is crucial to their
treatment and long-term health. If they experience unacceptable side
effects, they should tell the physician, because many options are available,
and the physician may be able to prescribe a different medication that has
fewer or less noticeable side effects.
HYPERTENSION
DYSRHYTHMIAS are abnormal heart rhythms. The heart may beat too fast
(tachycardia), too slowly (bradycardia), or irregularly. The most common
type of dysrhythmia is atrial fibrillation, which is a sporadic, rapid beating of
the atria that may or may not affect the ventricles. The most serious type of
dysrhythmia is ventricular fibrillation, in which disorganized electrical activity
in the heart causes the ventricles to quiver ineffectively instead of beating.
Most sudden cardiac deaths are caused by ventricular fibrillation.
Causes. Most dysrhythmias result from abnormal flow of electrical impulses
through the heart. Abnormal impulse conduction has many potential causes,
including electric shock, certain medications, some herbal supplements,
hypertension, previous heart attack, decreased blood flow to the heart,
coronary artery disease, heart valve disorders, weakening of the heart
muscle (cardiomyopathy), some genetic diseases, diabetes mellitus, sleep
apnea, electrolyte (potassium, sodium, and calcium) imbalances, excess
alcohol consumption, and drugs such as cocaine and amphetamines.
Signs and Symptoms. Dysrhythmias may cause signs and symptoms including
shortness of breath, dizziness or fainting, an unusually fast or slow heart
rate, a fluttering feeling in the chest, and chest pain.
Treatment. The first goal of treatment is to correct the underlying cause of the
dysrhythmia. Other treatment options include
 Vagal maneuvers to slow the heart rate. These include holding the
breath, straining (bearing down as if for a bowel movement), and putting
the face in cool water.
 Medications such as beta blockers and anti-dysrhythmics.
 Pacemakers.
 Radiofrequency catheter ablation. This procedure destroys a small
amount of heart tissue to change the flow of the electrical impulses
through the heart.
 Maze procedure; this operation forms scars in the atria to correct the
flow of electrical impulses through the heart.
 Implantation of an implantable cardioverter defibrillator (ICD) to
regulate the heart rhythm.
 Surgery to correct heart defects such as narrow coronary arteries.
 Electric shock (defibrillation) to reset heart rhythms.
 Cardiopulmonary resuscitation if there is no evidence of blood flow.
ANGINA is chest pain that occurs when the heart does not receive enough
oxygen to carry out its job of pumping blood Page 552 throughout the body. It
is not immediately life threatening, but if the reason for the angina is not
found and corrected, the angina may become unstable (difficult to treat and
less responsive to medications). This type of angina is a warning of serious
or life-threatening conditions.
Causes. Angina is caused by a narrowing of the coronary arteries. Arteries
may become too narrow due to coronary spasms or as a result of coronary
artery disease (atherosclerosis), in which fatty deposits accumulate in the
arteries.
Signs and Symptoms. The pain of angina is usually described as a tight feeling
in the chest. It is often brought about by stress or physical activity. When
the stress or activity stops, the pain usually goes away.
Treatment. A doctor should monitor patients with angina regularly. Most
patients with angina carry sublingual nitroglycerin with them to dilate the
coronary blood vessels and relieve the pain. Treatment must also address
the underlying cause of the angina to prevent more serious conditions such
as a heart attack or stroke. The physician may order several tests to
determine the cause of angina, such as an electrocardiogram (ECG), a stress
test, blood tests, chest X-rays, cardiac catheterization, or an
echocardiogram.
CORONARY ARTERY DISEASE (CAD), also called ATHEROSCLEROSIS, is an
accumulation of fatty deposits in the arteries as a result of too much glucose
in the blood. The deposits cause the arteries to become narrow, reducing the
amount of blood that can flow through them. CAD affects more Americans
than any other type of heart disease. The American Heart Association
estimates that one in three American adults has one or more types of
coronary artery disease.
Causes. This condition is usually caused by a buildup of fat, cholesterol, and
calcium in the arteries. The risk factors for developing CAD include high
levels of LDL (low-density lipoprotein) cholesterol in the blood, a diet high in
fat and cholesterol, smoking, high blood pressure, obesity, a lack of
exercise, and diabetes mellitus.
Signs and Symptoms. There are often no signs or symptoms until a heart attack
occurs. The most common symptoms include angina, shortness of breath,
tightness in the chest, fatigue, and swelling in the legs of feet (edema). As
with most cardiac conditions, the first line of defense against CAD is
prevention. CAD may be prevented or reduced by controlling high blood
pressure and high cholesterol, not smoking, eating healthy foods, engaging
in regular exercise, and treating any existing conditions such as diabetes or
atherosclerosis.
Treatment. Existing CAD is treated using lipid-lowering agents such as
Mevacor® or Lipitor®, aspirin therapy, and medications to slow a rapid heart
rate. The patient can help by adopting a low-fat diet, exercising moderately,
and not smoking. Severe CAD may require surgery such as coronary
angioplasty or coronary artery bypass grafting (CABG) to repair, widen, or
detour around narrowed coronary arteries.
CORONARY ARTERY DISEASE
A MYOCARDIAL INFARCTION (MI), commonly called a heart attack, is
nonreversible damage to the heart caused by a lack of oxygen. Historically,
MIs have been fatal, and they often still are, but with new treatments, more
and more people survive them. However, the body cannot replace the
damaged cardiac cells, so a heart attack can result in permanent damage to
the heart.
Causes. The causes and contributing factors include blockage of coronary
arteries as a result of atherosclerosis (CAD) and a blood clot that blocks the
flow of blood through an artery. Drugs such as cocaine can cause coronary
arteries to spasm, which may also cause an MI.
Signs and Symptoms. Common symptoms include recurring, squeezing chest
pain or angina; pain in the shoulder, arm, back, teeth, or jaw; chronic pain
in the upper abdomen; shortness of breath, especially on exertion; sweating
(diaphoresis); dizziness or fainting; and nausea or vomiting.
Treatment. The first treatment, if possible, is chewing an aspirin at the onset
of symptoms. In an unconscious patient who has no pulse and is not
breathing, cardiopulmonary resuscitation (CPR) should be administered.
Other immediate treatment options include the use of a defibrillator and
thrombolytic medications to destroy the blood clots that block a coronary
artery. It should be noted that thrombolytic drugs are effective only if begun
within 3 hours of the first symptom, so time is crucial. Surgery (angioplasty
or CABG) may be necessary to replace or repair blocked coronary arteries.
Long-term treatment includes anticoagulant medications such as heparin
and warfarin to thin the blood, and medications such as atenolol to slow the
heart rate.
AN ANEURYSM is a ballooned, weakened arterial wall. The most common
locations of aneurysms are the aorta and arteries in the brain, legs,
intestines, and spleen. An aortic aneurysm is a bulge in the wall of the aorta.
Most aortic aneurysms occur in the abdominal aorta (abdominal aortic
aneurysm), but some occur in the thoracic aorta (see Figure 25-15). Most
aortic aneurysms do not rupture; however, when they do, the resulting
hemorrhage is a life-threatening emergency.
FIGURE 25-15 Abdominal aneurysms can occur
without symptoms, but if they rupture they are frequently life threatening.
Causes. Most causes are unknown. One identified risk for developing an
aneurysm is atherosclerosis, which is usually associated with a highcholesterol diet. Smoking and obesity also increase the risk of
atherosclerosis. Congenital conditions may cause an aneurysm—some
individuals are born with weak aortic walls. A traumatic injury to the chest
also may be a risk factor. The risk of developing an aneurysm can be
reduced by not smoking, by losing excess weight, and by eating a low-fat,
low-cholesterol diet. Periodic screening is an option for patients with a family
history of aortic aneurysms.
Page 553Signs and Symptoms. There are usually no signs or symptoms of an
aneurysm, although hypertension may be present. When symptoms do exist,
the most common are a pulsation in the abdomen and back pain. A sudden
pain in the abdomen or back, dizziness, a fast pulse, or a loss of
consciousness can be a sign that an aneurysm has ruptured.
Treatment. The primary treatment is surgery to repair the aneurysm.
ENDOCARDITIS is an inflammation of the innermost lining of the heart,
including the heart valves.
Causes. Bacterial infections are the most common cause of endocarditis.
Patients are more susceptible to this condition if they have abnormal heart
valves.
Signs and Symptoms. Common signs and symptoms include weakness, fever,
excessive sweating, general body aches, difficulty breathing, and blood in
the urine.
Treatment. The treatment for this condition is intravenous antibiotics followed
by oral antibiotics for up to 6 weeks.
MYOCARDITIS is an inflammation of the muscular layer of the heart. It is
relatively uncommon but very serious because it leads to weakening of the
heart wall.
Causes. The most common cause of myocarditis is a viral infection, but it also
may be caused by exposure to certain chemicals, allergens, and bacteria.
Signs and Symptoms. Signs and symptoms include fever as well as chest pains
that feel like a heart attack. Difficulty breathing, decreased urine output,
fatigue, and fainting also may accompany myocarditis.
Treatment. Treatment normally includes steroids to reduce inflammation, bed
rest, and a low-sodium diet.
PERICARDITIS is inflammation of the pericardium, which is the group of
membranes that surround the heart.
Causes. This condition is most commonly caused by complications of viral or
bacterial infections. However, heart attacks and chest injuries also can lead
to pericarditis.
Signs and Symptoms. Symptoms include sharp, stabbing chest pains, especially
during deep breaths. Fever, fatigue, and difficulty breathing while lying down
are also common symptoms.
Treatment. Diuretics are used to remove excess fluids around the heart. If
bacteria caused the pericarditis, antibiotics are used as well. In chronic
cases, surgery may be required to remove part of the membranes
surrounding the heart. Because pericarditis can be very painful, treatment
also generally includes painkillers.
CONGESTIVE HEART FAILURE (CHF) is a slowly developing condition in which
the heart weakens over time. Eventually, the heart is no longer able to
pump enough blood to meet the body’s needs.
Causes. There are many risk factors for this condition, including smoking,
being overweight, a diet high in cholesterol, a lack of exercise,
atherosclerosis, history of MI, high blood pressure, a damaged heart valve,
excessive alcohol consumption, and diabetes mellitus. Congenital heart
defects (those present at birth) and drugs that weaken the heart (especially
cocaine, heroin, and some antineoplastic drugs for cancer) also may
contribute to the development of this disorder. Patients may reduce the risk
factors for CHF by controlling high blood pressure and high cholesterol, not
smoking, maintaining a healthy diet, engaging in regular exercise, and
treating any existing atherosclerosis or diabetes.
Signs and Symptoms. Signs and symptoms include shortness of breath;
constant wheezing; prominent neck veins; fluid retention that causes
swelling in the legs, feet, or abdomen; nausea; dizziness; and an irregular or
rapid heartbeat. (SeeFigure 25-16.)
FIGURE 25-16 When the heart muscle is damaged
and weak, a patient will suffer symptoms of heart failure.
Treatment. Common treatment options include medications to slow a rapid
heartbeat, diuretics to decrease edema and fluid accumulation in the lungs,
and medications to reduce blood pressure. In more serious cases, surgery to
repair defective heart valves or other heart defects, implantation of a cardiac
pacemaker, or a heart transplant may be needed.
HEART FAILURE OVERVIEW
LEFT-SIDE HEART FAILURE
RIGHT-SIDE HEART FAILURE
MITRAL VALVE PROLAPSE (MVP) is a condition in which the mitral valve falls
into the left atrium during systole. This prevents the valve from sealing
properly. In severe cases, blood may flow back into the atrium. Although
most cases are mild, MVP can become worse over time. It also increases the
risk of heart valve infections and endocarditis.
Page 554 Causes. The cause of MVP is unknown in most cases. However, it may
be hereditary, and it has been linked to autonomic nervous system
disorders.
Signs and Symptoms. In mild cases, symptoms may not develop. In more
severe cases, palpitations, shortness of breath, and chest pain may occur.
Treatment. No treatment is needed for mild cases. Medications are used to
treat symptoms and to help prevent complications such as infection. In very
severe cases, surgery may be required to repair the valve.
STENOSIS is an abnormal narrowing of a body passage. In the
heart, AORTIC STENOSIS is a narrowing of the aortic valve, and MITRAL
STENOSIS is a narrowing of the mitral valve. Stenosis causes these valves to
fail to open fully. As a result, blood flow from the heart decreases and
pressure inside the left ventricle increases. In severe cases, stenosis may
cause heart dysrhythmias or congestive heart failure.
Causes. Aortic or mitral stenosis can be congenital or may occur later in life.
Noncongenital cases are common in patients who have had rheumatic fever.
Signs and Symptoms. Common signs and symptoms include shortness of
breath, angina, palpitations, dizziness, weakness, and fatigue.
Treatment. Mild stenosis may not need treatment. If the stenosis is severe
enough to cause dysrhythmias or CHF, medications are used to control these
disorders. If the patient has had rheumatic fever, antibiotics may also be
prescribed. In some cases, surgery or valvuloplasty may be performed.
MURMURS are simply abnormal heart sounds. Normally, heart sounds are
clear, strong, and smooth as valves close completely and blood flows over
the lining of the heart with no resistance. Not all murmurs indicate a heart
disorder. Murmurs are graded from 1 to 6; 1 is barely audible and the least
serious.
Causes. Not all the causes of heart murmurs are known. In children, the
failure of the foramen ovale or ductus arteriosis to close completely after
birth can cause murmurs. Other causes include stress and defective heart
valves that do not close completely.
Signs and Symptoms. The signs and symptoms vary considerably depending on
the cause and severity of the heart murmur. Severe symptoms include
weakness, pallor, edema (fluid retention), and other signs commonly
associated with heart failure.
Treatment. In many cases, no treatment is required. Surgery to correct
valvular defects or other heart defects may be needed in more serious
cases.
THROMBOPHLEBITIS is a condition in which a blood clot blocks or partially
blocks blood flow in a vein, causing inflammation, swelling, and pain. It most
commonly occurs in the leg veins. The danger of thrombophlebitis is that the
blood clot may break loose, becoming an embolus that moves through the
circulatory system. The embolus can cause major problems, depending on
where it lodges in the body. If it blocks a blood vessel in the lungs, it
becomes a pulmonary embolism (obstruction in the lungs). If it blocks a
coronary artery, it may cause a myocardial infarction (heart attack). If it
blocks an artery in the brain, it may cause a cerebrovascular accident
(stroke).
Causes. The causes and risk factors include prolonged inactivity, oral
contraceptives, postmenopausal hormone replacement therapy (HRT),
certain types of cancer, paralysis in the arms or legs, the presence of a
venous catheter, a family history of thrombophlebitis, varicose veins, and
trauma to veins.
Signs and Symptoms. The most common symptoms are tenderness and pain in
the affected area; redness, swelling, and tenseness of the affected areas;
fever; and a positive Homan’s sign (pain behind the knee that is caused by a
blood clot, when the foot is forceably dorsiflexed).
Treatment. This disorder is most often treated by applying heat to the
affected area, wearing support stockings, and elevating the legs. Antiinflammatory medications and anticoagulants may be prescribed. In some
cases, surgery may be performed to remove the clot.
VARICOSE VEINS are twisted, dilated veins usually seen in the legs. They
affect women more often than men. When varicose veins occur in the
rectum, they are called hemorrhoids.
Page 555Causes. Varicose veins may be caused by prolonged sitting or standing,
damage to valves in the veins, a loss of elasticity in the veins, obesity,
pregnancy, oral contraceptives, or hormone replacement therapy. Family
history also seems to play a part in the development of varicose veins. In
some cases, varicose veins may be prevented or at least minimized through
exercise and elevation of the legs.
Signs and Symptoms. Signs and symptoms include discomfort in the legs,
discolorations around the ankles, clusters of veins, and enlarged, dark veins
seen through skin.
Treatment. The treatment of varicose veins includes the following:
 Sclerotherapy, a procedure that prevents blood from flowing through
varicose veins
 Laser surgery to prevent blood from flowing through affected veins
SUMMARY
LEARNING
OUTCOMES
OF
LEARNING
OUTCOMES
KEY POINTS
The structures of the heart include the pericardium, epicardium,
1. 25.1Describe the myocardium, and endocardium. The chambers of the heart consist
structures of the of the atria (upper chambers) and the ventricles (lower chambers).
The four valves within the heart are the tricuspid, the bicuspid, the
heart and the
function of each. pulmonary semilunar, and the aortic semilunar valves.
1. 25.2Explain the
cardiac cycle,
including the
cardiac
conduction
system.
One cardiac cycle consists of one complete heartbeat. The atria
contract and relax together, and the ventricles contract and relax
together. As each chamber contracts, associated valves open and
close to control the flow of blood through the heart. Contractions
are initiated by the cardiac conduction system, which consists of
the sinoatrial node, the atrioventricular node, the bundle of His,
bundle branches, and Purkinje fibers.
Types of blood vessels include arteries and arterioles, which take
blood from the heart to the body; veins and venules, which carry
blood back from the body to the heart; and capillaries, which act
as the connectors between the arterioles and venules. The largest
artery in the body is the aorta. Other major arteries include lingual,
facial, occipital, maxillary, ophthalmic, axillary, brachial, ulnar,
radial, intercostals, lumbar, external iliac, common iliac, femoral,
1. 25.3Differentiate popliteal, and tibial. The largest veins in the body are the superior
and inferior venae cavae. Other major veins are jugular,
among the
brachiocephalic, axillary, brachial, ulnar, radial, intercostals,
different types
of blood vessels azygos, iliac, femoral, popliteal, saphenous, hepatic, gastric,
their functions. splenic, mesenteric, and hepatic portal.
1. 25.4Compare
the various
types of
circulation.
Pulmonary circulation is the path the blood travels from the right
side of the heart to the lungs and back to the left side of the heart.
Its purpose is to oxygenate the blood and remove waste gases.
Systemic circulation is the route blood takes from the left side of
the heart, throughout the body, and back to the right side of the
heart. Its purpose is to deliver oxygen and nutrients to body cells
and to remove metabolic wastes from the cells. Coronary
circulation delivers oxygenated blood to the coronary arteries and
removes metabolic wastes from the heart muscle.
Page 556 Blood pressure is the force exerted on the inner wall of
1. 25.5Explain
blood vessels by blood as it flows through vessels. It is highest in
blood pressure
and tell how it is arteries and lowest in veins. Clinically, blood pressure is the force
of blood within the arteries. Blood pressure is largely controlled
controlled.
by the amount of blood pumped out of the heart, but various other
events also may raise and lower blood pressure.
1. 25.6Describe the
causes, signs
and symptoms,
and treatments
of various
diseases and
disorders of the
cardiovascular
system.
Many different types of cardiac and blood diseases are described
within this chapter. The signs, symptoms, and treatments are as
varied as the diseases themselves. The last section of this chapter
outlines the most common of these diseases, their signs and
symptoms, and their treatments.
Vein stripping, which involves removing affected veins
Insertion of a catheter into the affected veins in order to destroy them
Endoscopic vein surgery to close off affected veins
C A S E S T U D Y C R I T I C A L T H I N K I N G



© McGraw-Hill Education
Recall John Miller from the beginning of this chapter. Now that you have
completed this chapter, answer the following questions regarding his case.
1. What symptoms suggest that this patient is suffering from coronary
artery disease and not some other disorder?
2. Why is it important to test the heart under stress rather than obtaining a
resting echocardiogram?
3. Why is a cardiac catheterization needed in addition to the stress
echocardiogram?
4. What lifestyle changes should this patient make to prevent future heart
attacks?
E X A M P R E P A R A T I O N Q U E S T I O N S
1. (LO 25.1) Which heart valve is between the left atrium and left
ventricle?
a.
Tricuspid
b.
Bicuspid
c.
Pulmonary semilunar
d.
Aortic semilunar
e.
Right atrioventricular
2. (LO 25.2) Which part of the cardiac conduction system receives
electrical impulses from the bundle branches?
a.
AV node
b.
SA node
c.
Bundle of His
d.
Purkinje fibers
e.
Chordae tendineae
3. (LO 25.3) In which blood vessels does the exchange of oxygen and
waste gases occur?
a.
Arteries
b.
Arterioles
c.
Veins
d.
Venules
e.
Capillaries
4. (LO 25.4) Which chamber of the heart receives oxygen ated blood from
the lungs?
a.
Left atrium
b.
Right atrium
c.
Pulmonary trunk
d.
Left ventricle
e.
Right ventricle
5. Page 557 (LO 25.6) Which of the following causes of chest pain
is not cardiac in nature?
a.
Angina
b.
Pericarditis
c.
Heartburn
d.
Myocardial infarction
e.
Coronary spasms
6. (LO 25.5) The amount of pressure in the arteries when the ventricles
contract is called
a.
Cardiac output
b.
Vasodilation
c.
Vasoconstriction
d.
Diastole
e.
Systole
7. (LO 25.1) The layer of the heart wall that is made mostly of cardiac
muscle that allows the heart to contract and relax is the
a.
Pericardial space
b.
Myocardium
c.
Epicardium
d.
Visceral pericardium
e.
Endocardium
8. (LO 25.6) A condition in which a blood clot and inflammation develop in
a vein is
a.
Mitral stenosis
b.
Varicose veins
c.
Thrombophlebitis
d.
Myocardial infarction
e.
Pericarditis
9. (LO 25.3) The largest veins in the body are the
a.
Hepatic portal veins
b.
Jugular veins
c.
Venae cavae
d.
Pulmonary veins
e.
Femoral veins
10.
(LO 25.5) The total amount of blood pumped out of the heart in 1
minute is known as the
a.
Cardiac output
b.
Systolic pressure
c.
Systemic circulation
d.
Coronary sinus
e.
Diastolic pressure
MEDICAL TERMINOLOGY PRACTICE
Analyze the following medical terms, presented throughout the chapter.
Using a medical dictionary (or Appendix I) place a / mark between each word
part. Define each word part and then define the whole word.
EXAMPLE: vaso / spasm = vaso means “vessel” + spasm means “cramp or
twitching”
VASOSPASM means “twitching or cramping of a vessel.”
1. atherosclerosis
2. atrioventricular
3. baroreceptor
4. echocardiogram
5. electrocardiogram
6. intercostal
7. myocardium
8. pericarditis
9. stenosis
10.
thrombophlebitis
11.
vasoconstriction
12.
ventricular