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Learning Outcomes
Chapter
On completion of this chapter, you will be able to:
1. State the description and primary functions of the organs/structures of the car-
diovascular system.
2. Explain the circulation of blood through the chambers of the heart.
3. Identify and locate the commonly used sites for taking a pulse.
4. Explain blood pressure.
5. Recognize terminology included in the ICD-10-CM.
6. Analyze, build, spell, and pronounce medical words.
7. Comprehend the drugs highlighted in this chapter.
8. Describe diagnostic and laboratory tests related to the cardiovascular system.
9. Identify and define selected abbreviations.
10. Apply your acquired knowledge of medical terms by successfully completing
the Practical Application exercise.
Cardiovascular System^9
Anatomy and Physiology
The cardiovascular (CV) system, also called the circulatory system, circulates blood to all parts of the body by the action of the heart. This process provides the body’s cells with oxygen and nutritive ele- ments and removes waste materials and carbon dioxide. The heart, a muscular pump, is the central organ of the system. It beats approximately 100,000 times each day, pumping roughly 8,000 liters of blood, enough to fill about 8,500 quart-sized milk cartons. Arteries, veins, and capillaries comprise the network of vessels that transport blood (fluid consisting of blood cells and plasma) throughout the body. Blood flows through the heart, to the lungs, back to the heart, and on to the various body parts. Table 9.1 provides an at-a-glance look at the cardiovascular system. Figure 9.1 shows a schematic overview of the cardiovascular system.
Heart The heart is the center of the cardiovascular system from which the various blood vessels originate and later return. It is slightly larger than a person’s fist and weighs approximately 300 g in the average adult. It lies slightly to the left of the midline of the body, behind the sternum (see Figure 9.2). The heart has three layers or linings.
- Endocardium. The inner lining of the heart.
- Myocardium. The muscular middle layer of the heart.
- Pericardium. The outer membranous sac surrounding the heart.
Circulation of Blood through the Chambers of the Heart The heart is a pump and is divided into the right and left heart by a partition called the septum. Each side contains an upper and lower chamber. See Figure 9.3. The atria, or upper chambers, are separated by the interatrial septum. The ventricles, or lower chambers, are separated by the interventricular septum. The atria receive blood from the various parts of the body. The ventricles pump blood to body parts. Valves control the intake and outflow of blood in the heart chambers. Figure 9.4 shows the function- ing of the heart valves and flow of blood through the heart.
Table 9.1 Cardiovascular System at-a-Glance
Organ/Structure Primary Functions/Description
Heart The muscular pump that circulates blood through the heart, the lungs (pulmonary circulation), and the rest of the body (systemic circulation) Arteries Branching system of vessels that transports blood from the right and left ventricles of the heart to all body parts; transports blood away from the heart Veins Vessels that transport blood from peripheral tissues back to the heart Capillaries Microscopic blood vessels that connect arterioles with venules; facilitate passage of life-sustaining fluids containing oxygen and nutrients to cell bodies and the removal of accumulated waste and carbon dioxide Blood Fluid consisting of formed elements (erythrocytes, thrombocytes, leukocytes) and plasma. It is a specialized bodily fluid that delivers necessary substances to the body’s cells (oxygen, foods, salts, hormones) and transports waste products (carbon dioxide, urea, lactic acid) away from those same cells. Blood is circulated around the body through blood vessels by the pumping action of the heart. See Chapter 10, Blood and Lymphatic System, for a further discussion of blood.
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Figure 9.3 Interior view of the heart chambers with tissues of the heart (endocardium, myocardium, and pericardium).
Left ventricle
Endocardium Myocardium Pericardium
Superior vena cava
Aorta
Pulmonary trunk
Right atrium
Right ventricle
Inferior vena cava
Left atrium
Pulmonary valve
Tricuspid valve
Aortic valve Mitral (Bicuspid) valve
Figure 9.4 The functioning of the heart valves and blood flow.
To lung Left pulmonary artery (branches) To lung Right pulmonary artery (branches)
From body
From body To body
Right atrium Tricuspid valve Right ventricle
Inferior vena cava
From lung Right pulmonary vein (branches)
Aorta
Left ventricle Interventricular septum Myocardium (heart muscle)
Apex
Left atrium Aortic valve Mitral (bicuspid) valve
Descending aorta
From lung Left pulmonary vein (branches)
Superior vena cava
Pulmonary valve
Cardiovascular System • 259
right atrium
The right upper portion of the heart is called the right atrium (RA). It is a thin-walled space that receives blood from the upper and lower parts of the body (except the lungs). Two large veins, the superior vena cava and inferior vena cava, bring deoxy- genated blood into the right atrium. Deoxygenated blood fills the right atrium before passing through the tricuspid (atrioventricular) valve and into the right ventricle.
right ventricle
The right lower portion of the heart is called the right ventricle (RV). It receives blood from the right atrium through the tricuspid valve. When filled, the RV contracts. This creates pressure, closing the right atrium and forcing open the pulmonary (semilunar) valve, sending blood into the left and right pulmonary arteries, which carry it to the lungs. The pulmonary artery is the only artery in the body that carries blood deficient in oxygen. In the lungs, the blood gives up wastes and takes on oxygen as it passes through capillary beds into veins. Oxygenated blood leaves the lungs through the left and right pulmonary veins, which carry it to the heart’s left atrium. The pulmonary veins are the only veins in the body that carry oxygen-rich (oxygenated) blood. The circulation of blood through the vessels from the heart to the lungs and then back to the heart again is the pulmonary circulation.
left atrium
The left upper portion of the heart is called the left atrium (LA). It receives blood rich in oxygen as it returns from the lungs via the left and right pulmonary veins. As oxygen- ated blood fills the LA, it creates pressure that forces open the mitral (bicuspid) valve and allows the blood to fill the left ventricle.
left ventricle
The left lower portion of the heart is called the left ventricle (LV). It receives blood from the left atrium through the mitral valve. When filled, the LV contracts. This creates pressure closing the mitral valve and forcing open the aortic valve. The oxygenated blood from the LV flows through the aortic valve and into a large artery known as the aorta and from there to all parts of the body (except the lungs) via a branching system of arteries and capillaries.
fyi
Pediatric cardiologists have recognized more than 50 congenital heart defects. If the left side of the heart is not completely separated from the right side, various septal defects develop. If the four chambers of the heart do not develop normally, complex anomalies form, such as tetralogy of Fallot (TOF), a congenital heart condition involving four defects: pulmonary artery stenosis, ventricular septal defect (VSD), displacement of the aorta to the right, and hypertrophy of the right ventricle.
Heart Valves The valves of the heart are located at the entrance and exit of each ventricle and, as you learned in the preceding section, control the flow of blood within the heart. See Figure 9.5.
Cardiovascular System • 261
Conduction System of the Heart The autonomic nervous system controls the rate and rhythm of the heartbeat. It is normally generated by specialized neuromuscular tissue of the heart that is capable of causing cardiac muscle to contract rhythmically. This tissue of the heart comprises the sinoatrial node, the atrioventricular node, and the atrioventricular bundle. See Figure 9.7.
Figure 9.6 Coronary circulation. (A) Coronary vessels portraying the complexity and extent of the coronary circulation. (B) Coronary vessels that supply the posterior surface of the heart.
Anterior interventricular artery (descending branch)
Right coronary artery
Small cardiac vein
Anterior cardiac veins Marginal branch
A
Great cardiac vein Circumflex branch Coronary sinus Posterior cardiac vein
Right coronary artery
Small cardiac vein
Marginal branch
Posterior interventricular vein Middle cardiacvein (descending branch)
B
Pulmonary trunk
Left coronary artery
Great cardiac vein
Aortic arch
Sinoatrial node (pacemaker) Internodal pathway Atrioventricular node
Atrioventricular bundle (Bundle of His)
Bundle branches
Purkinje fibers
Aorta
Purkinje fibers
Interventricular septum
Superior vena cava
Left atrium
Figure 9.7 Conduction system of the heart.
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sinoatrial node (sa node) Called the pacemaker of the heart, the SA node is located in the upper wall of the right atrium, just below the opening of the superior vena cava. It consists of a dense network of Purkinje fibers ( atypical muscle fibers ) considered to be the source of impulses initiat- ing the heartbeat. Electrical impulses discharged by the SA node are distributed to the right and left atria and cause them to contract.
atrioventricular node (av node) Located beneath the endocardium of the right atrium, the AV node transmits electrical impulses to the bundle of His ( atrioventricular bundle ).
atrioventricular bundle (bundle of his) The atrioventricular bundle or bundle of His forms a part of the conduction system of the heart. It is a collection of heart muscle cells specialized for electrical conduction that transmits the electrical impulses from the AV node to the point of the apex of the fascicular branches. The bundle of His branches into the two bundle branches that run along the interventricular septum. The bundles give rise to thin filaments known as Purkinje fibers. These fibers distribute the impulse to the ventricular mus- cle. Together, the bundle branches and Purkinje network comprise the ventricular conduction system. The average adult heartbeat ( pulse ) is between 60 and 90 beats per minute. The rate of the heartbeat can be affected by emotions, smoking, disease, body size, age, stress, the environment, and many other factors. The heart’s electrical activity can be recorded by an electrocardiogram (ECG, EKG), which provides valuable information in diagnosing cardiac abnormalities, such as myocardial damage and arrhythmias (see the section Diagnostic and Laboratory Tests and Figure 9.38).
Blood Vessels
There are three main types of blood vessels: arteries, veins, and capillaries. Blood cir- culates throughout the body through their pathways.
Arteries The arteries constitute a branching system of vessels that transports blood away from the heart to all body parts. See Figure 9.8. In a normal state, arteries are elastic tubes that recoil and carry blood in pulsating waves. All arteries have a pulse, reflecting the rhythmical beating of the heart; however, certain points are commonly used to check the rate, rhythm, and condition of the arterial wall. A person’s pulse can be felt in a place that allows for an artery to be compressed against a bone. The most commonly used sites for taking a pulse are the radial artery, the brachial artery, and the carotid artery. See Table 9.2 and Figure 9.9. The pulse rate can also be measured by using a stethoscope ( auscultation ) and counting the heartbeat for 1 full minute. This is known as the apical pulse and is taken over the heart itself. In contrast with other pulse sites, the apical pulse site is unilateral and is located at the apex of the heart or at the fifth intercostal space, just to the left of the midclavicular line. It is commonly used to check pulse rate in infants and children, and when the radial pulse is difficult to palpate ( to feel by touch ).
264 • Chapter Nine
Table 9.2 Pulse Checkpoints
Carotid
Brachial
Radial
Femoral
Popliteal
Dorsalis pedis
Temporal
Figure 9.9 Primary pulse points of the body.
Checkpoint Site/Use
Temporal Temple area of the head. Used to control bleeding from the head and scalp and to monitor circulation. Carotid Neck. In an emergency (cardiac arrest), most readily accessible site. Brachial Antecubital space of the elbow. Most common site used to check blood pressure. Radial Radial (thumb side) of the wrist. Most common site for taking a pulse. Femoral Groin area. Monitor circulation. Popliteal Behind the knee. Monitor circulation. Dorsalis pedis Dorsal surface of the foot. Assess for peripheral artery disease (PAD).
Veins Veins are the vessels that transport blood from peripheral tissues back to the heart. In a normal state, veins have thin walls and valves that prevent the backflow of blood. The great saphenous vein is the most important superficial vein of the lower limb. The pulmonary veins carry oxygenated blood from the lungs to the heart. The superior and inferior venae cavae carry deoxygenated blood from the upper and lower systemic circulation. See Figure 9.10.
Capillaries The capillaries are microscopic blood vessels with single-celled walls that connect arteri- oles ( small arteries ) with venules ( small veins ). See Figure 9.11. Blood passing through capil- laries gives up the oxygen and nutrients carried to this point by the arteries and picks up waste and carbon dioxide as it enters veins. Veins lead away from the capillaries as tiny vessels and increase in size until they join the superior and inferior venae cavae as they return to the heart. The extremely thin walls of capillaries facilitate passage of oxygen and nutrients to cell bodies and the removal of accumulated waste and carbon dioxide.
Cardiovascular System • 265
Figure 9.10 Major veins of the systemic circulation.
Superior vena cava
Hepatic portal vein
Superior mesenteric vein Inferior vena cava Ulnar vein Radial vein Common iliac vein External iliac vein Internal iliac vein
Digital veins
Subclavian vein Right and left brachiocephalic veins
Cephalic vein
Brachial vein
Basilic vein
Median cubital vein
Renal vein
External jugular vein Internal jugular vein
Femoral vein Great saphenous vein
Popliteal vein
Posterior tibial vein
Anterior tibial vein
Fibular vein
Cardiovascular System • 267
Figure 9.12 Blood pressure measurement.
Axillary artery
Radial artery
Release valve Bulb
Blood pressure cuff (over brachial artery)
Stethoscope over brachial artery
Digital readout
Deflated blood pressure cuff
Brachial artery open
Artery closed
Artery begins to open
Inflated blood pressure cuff
Gradual deflation of cuff
pulse pressure
The pulse pressure is the difference between the systolic and diastolic readings. This reading indicates the tone of the arterial walls. The normal pulse pressure is found when the systolic pressure is about 40 points higher than the diastolic reading. For example, if the blood pressure is 120/80, the pulse pressure would be 40. A pulse pres- sure over 50 points or under 30 points is considered abnormal.
268 • Chapter Nine
Anatomy and Physiology
Write your answers to the following questions.
1. The cardiovascular system includes:
a. ________________________________ b. ________________________________
c. ________________________________ d. ________________________________
2. Name the three layers of the heart.
a. ________________________________ b. ________________________________
c. ________________________________
3. The heart weighs approximately ________________________ grams.
4. The ________________________ or upper chambers of the heart are separated by the
________________________ septum.
5. The ________________________ or lower chambers of the heart are separated by the
________________________ septum.
6. A/An ________________________ records the heart’s electrical activity.
7. The ________________________ ________________________ ________________________ controls
the heartbeat.
8. The ________________________ ________________________ is called the pacemaker of the heart.
9. Together, the bundle branches and ________________________ comprise the ventricular
conduction system.
10. Name the three primary pulse points and state their locations on the body.
a. ______________________________ located _______________________________
b. ______________________________ located _______________________________
c. ______________________________ located _______________________________
11. Define the following terms:
a. Blood pressure _________________________________________________________________________
b. Pulse pressure __________________________________________________________________________
Study and Review I
270 • Chapter Nine
This section provides the foundation for learning medical terminology. Review the following alphabetized
word list. Note how common prefixes and suffixes are repeatedly applied to word roots and combining
forms to create different meanings. The word parts are color-coded: prefixes are yellow, suffixes are blue,
roots/combining forms are red. A combining form is a word root plus a vowel. The chart below lists the
combining forms for the word roots in this chapter and can help to strengthen your understanding of how
medical words are built and spelled.
Remember These Guidelines
- If the suffix begins with a vowel, drop the combining vowel from the combining form and add the suffix. For example, ather/o (fatty substance) + -oma (tumor) becomes atheroma.
- If the suffix begins with a consonant, keep the combining vowel and add the suffix to the combin- ing form. For example, angi/o (vessel) + -plasty (surgical repair) becomes angioplasty.
You will find that some terms have not been divided into word parts. These are common words or spe-
cialized terms that are included to enhance your medical vocabulary.
Combining Forms of the Cardiovascular System
angi/o vessel mitr/o mitral valve
angin/o to choke my/o muscle
arteri/o artery occlus/o to close up
ather/o fatty substance, porridge ox/i oxygen
atri/o atrium oxy sour, sharp, acid
auscultat/o listen to palpit/o throbbing
cardi/o heart pector/o chest
chol/e bile phleb/o vein
circulat/o circular pulmon/o lung
claudicat/o to limp rrhythm/o rhythm
corpor/o body scler/o hardening
cyan/o dark blue sept/o a partition
dilat/o to widen sin/o a curve
dynam/o power sphygm/o pulse
ech/o reflected sound sten/o narrowing
electr/o electricity steth/o chest
embol/o a throwing in thromb/o clot of blood
glyc/o sweet, sugar valvul/o valve
hem/o blood vas/o vessel
infarct/o infarct (necrosis of an area) vascul/o small vessel
isch/o to hold back ven/o vein
lipid/o fat ventricul/o ventricle
lun/o moon vers/o turning
man/o thin
Building Your Medical Vocabulary
Cardiovascular System • 271
Medical Word Word Parts Definition
Part Meaning
anastomosis (ă-năs˝ tō-mō´sĭs)
anastom -osis
opening condition
Surgical connection between blood vessels or the joining of one hollow or tubular organ to another
aneurysm (ăn´ ū-rĭzm)
Abnormal widening or ballooning of a portion of an artery due to weakness in the wall of the blood vessel. See Figure 9.13.
angina pectoris (ăn´ jĭ-nă pĕk´ tōr˝ĭs)
angin (a) pector -is
to choke chest pertaining to
Chest pain that occurs when diseased blood vessels restrict blood flow to the heart. It is the most common symptom of coronary artery disease (CAD) and is often referred to as angina. The pain can radiate to the neck, jaw, or left arm. It is often described as a crushing, burning, or squeezing sensation. Patients with CAD can present with stable angina pectoris, unstable angina pectoris, or a myocardial infarction (MI), a heart attack.
angioma (ăn˝ jĭ-ō´ mă)
angi -oma
vessel tumor
Tumor of a blood vessel. See Figure 9.14.
Aneurysm Inferior vena cava
Right kidney
Abdominal aorta
Figure 9.13 Ruptured abdominal aortic aneurysm.
insights In ICD-10-CM, angina pectoris includes codes I20.0–I20.9. With^ stable angina, the pattern of frequency, intensity, ease of provocation, and duration does not change over a period of sev- eral weeks. With unstable angina, the pattern of chest pain changes abruptly.
Figure 9.14 Infarction angioma. (Courtesy of Jason L. Smith, MD)
Cardiovascular System • 273
Medical Word Word Parts Definition
Part Meaning
arteritis (ăr˝ tĕ-rī´ tĭs)
arter -itis
artery inflammation
Inflammation of an artery. See Figure 9.15.
artificial pacemaker Electronic device that stimulates impulse initiation within the heart. It is a small, battery-operated device that helps the heart beat in a regular rhythm. See Figure 9.16.
Figure 9.15 Temporal arteritis. (Courtesy of Jason L. Smith, MD)
Pacemaker
Figure 9.16 A permanent epicardial pacemaker. The pulse generator can be placed in subcutaneous pockets in the subclavian or abdominal regions.
fyi
A team of investigators at Children’s Hospital Los Angeles and the University of Southern California have developed the first fully implantable micropacemaker designed for use in a fetus with complete heart block. The team has done preclinical testing and optimization, as reported in a recent issue of the journal Heart Rhythm, and in 2015 the micropacemaker was designated a humanitarian use device (HUD)* by the U.S. Food and Drug Administration (FDA). The investigators anticipate the first human use of the device in the near future.
- A HUD is a “medical device intended to benefit patients in the treatment or diagnosis of a disease or condition that affects or is manifested in fewer than 4,000 individuals in the United States per year” (From Code of Federal Regulations, Title 21, Chapter 1, Part 814, Subpart A, Section 814.3, U.S. Food and Drug Administration.).
274 • Chapter Nine
Medical Word Word Parts Definition
Part Meaning
atheroma (ăth˝ ĕr-ō´ mă)
ather
-oma
fatty substance, porridge tumor
Tumor of an artery containing a fatty substance
atherosclerosis (ăth˝ ĕr-ō-sklĕ-rō´ sĭs)
ather/o
scler -osis
fatty substance, porridge hardening condition
Pathological condition of the arteries characterized by the buildup of fatty substances (cholesterol deposits and triglycerides) and hardening of the walls
auscultation (aws˝ kŭl-tā´ shŭn)
auscultat -ion
listen to process
Method of physical assessment using a stethoscope to listen to sounds within the chest, abdomen, and other parts of the body. See Figure 9.17.
automated external defibrillator (AED) (aw´ tō-māt- ĕd eks-tĕr´ năl dē-fĭb´ rĭ-lā-tor)
Portable automatic device used to restore normal heart rhythm to patients in cardiac arrest. An AED is applied outside the body. It automatically analyzes the patient’s heart rhythm and advises the rescuer whether a shock is needed to restore a normal heartbeat. If the patient’s heart resumes beating normally, the heart has been defibrillated.
bicuspid (bī-kŭs´ pĭd)
bi- -cuspid
two point
Valve with two cusps; pertaining to the mitral valve
bradycardia (brăd˝ ĭ-kăr´ dĭ-ă)
brady- card -ia
slow heart condition
Abnormally slow heartbeat defined as fewer than 60 beats per minute
bruit (brōōt)
Pathological noise; a sound of venous or arterial origin heard on auscultation
cardiac (kăr´ dĭ-ăk)
cardi -ac
heart pertaining to
Pertaining to the heart
cardiac arrest Loss of effective heart function, which results in cessation of functional circulation. Sudden cardiac arrest (SCA) results in sudden death.
Figure 9.17 During auscultation, sounds can be heard via a stethoscope. Source: Pearson Education, Inc.
