To the Reader

To the Reader





This book was written with the intent of making the subject of and master the essential content for your current as well as fu-

pathophysiology an exciting exploration that relates normal ture needs.

body functioning to the physiologic changes that participate in It is essential for any professional to use and understand the

disease production and occur as a result of disease, as well as vocabulary of his or her profession. Throughout the text, you

the body’s remarkable ability to compensate for these changes. will encounter terms in italics. This is a signal that a word and

Indeed, it is these changes that represent the signs and symp- the ideas associated with it are important to learn. In addition,

toms of disease. two aids are provided to help you expand your vocabulary and

Using a book such as this can be simplified by taking the improve your comprehension of what you are reading: the

time to find what is in the book and how to locate information glossary and the list of prefixes and suffixes.

when it is needed. The table of contents at the beginning of the The glossary contains concise definitions of frequently en-

book provides an overall view of the organization and content countered terms. If you are unsure of the meaning of a term

of the book. It also provides clues as to the relationships among you encounter in your reading, check the glossary in the back

areas of content. For example, the location of the chapter on of the book before proceeding.

neoplasia within the unit on cell function and growth indicates The list of prefixes and suffixes is a tool to help you derive the

that neoplasms are products of altered cell growth. The index, meaning of words you may be unfamiliar with and increase

which appears at the end of the book, can be viewed as a road your vocabulary. Many disciplines establish a vocabulary by

map for locating content. It can be used to quickly locate re- affixing one or more sounds or letters to the beginning or end

lated content in different chapters of the book or to answer of a word or base to form a derivative word. Prefixes are added

questions that come up in other courses. to the beginning of a word or base, and suffixes are added to

the end. If you know the meanings of common prefixes and

suffixes, you can usually derive the meaning of a word, even if

ORGANIZATION you have never encountered it before. A list of prefixes and suf-

fixes common to pathophysiology can be found on the inside

The book is organized into units and chapters. The units iden- covers.

tify broad areas of content, such as alterations in the circulatory

system. The chapters focus on specific areas of content, such as

heart failure and circulatory shock. The chapter outline that ap- BOXES

pears at the beginning of each chapter provides an outline of

the content in the chapter. Icons identify specific content related Boxes are used throughout the text to summarize and high-

light key information. You will encounter two types of boxes:

to infants and children , pregnant women, , and older Key Concept Boxes and Summary Boxes.

adults . One of the ways to approach learning is to focus on the

major ideas or concepts rather than trying to memorize a list

Many of the units have a chapter that contains essential in- of related and unrelated bits of information. As you have

formation about the structures being discussed in the unit. probably already discovered, it is impossible to memorize

These chapters provide the foundation for understanding the everything that is in a particular section or chapter of the

pathophysiology content presented in the subsequent chapters. book. First, your brain has a difficult time trying to figure out

where to store all the different bits of information. Secondly,

your brain doesn’t know how to retrieve the information

READING AND LEARNING AIDS when you need it. Thirdly, memorized lists of content can

seldom be applied directly to an actual clinical situation.

In an ever-expanding world of information you will not be able

The Key Concept Boxes guide you in identifying the major

to read, let alone remember, everything that is in this book, or

ideas or concepts that form the foundation for truly under-

in any book, for that matter. With this in mind, we have devel- standing the major areas of content. When you understand

oped a number of special features that will help you focus on



xiii

xiv To the Reader





the concepts in the Key Concept boxes, you will have a TABLES AND CHARTS

framework for remembering and using all of the facts given

in the text. Tables and charts are designed to present complex infor-

mation in a format that makes it more meaningful and eas-

KEY CONCEPTS

COMPONENTS OF THE IMMUNE SYSTEM

ier to remember. Tables have two or more columns, and are

■ The immune system consists of immune cells; the

often used for the purpose of comparing or contrasting

central immune structures (the bone marrow and information. Charts have one column and are used to sum-

thymus), where immune cells are produced and ma-

ture; and the peripheral immune structures (lymph marize information.

nodes, spleen, and other accessory structures),

where the immune cells interact with antigen. TABLE 6-5 Manifestations of Hypokalemia and Hyperkalemia

■ The immune cells consist of the lymphocytes (T and Hypokalemia Hyperkalemia

B lymphocytes), which are the primary cells of the

immune system, and the accessory cells such as the Laboratory Values Laboratory Values

macrophages, which aid in processing and presenta- Serum potassium 5.0 mEq/L

tion of antigens to the lymphocytes. Thirst and Urine

■ Cytokines are molecules that form a communication Increased thirst

Inability to concentrate urine with polyuria and

link between immune cells and other tissues and

urine with low specific gravity

organs of the body.

Effects of Changes in Membrane Potentials Effects of Changes in Membrane Potentials

■ Recognition of self from nonself by the immune cells in Neural and Muscle Function on Neural and Muscle Function

depends on a system of MHC membrane molecules Gastrointestinal Gastrointestinal

that differentiate viral-infected and abnormal cells Anorexia, nausea, vomiting Nausea, vomiting

from normal cells (MHC I) and identify immune cells Abdominal distention Intestinal cramps

from other types of cells (MHC II). Paralytic ileus (severe hypokalemia) Diarrhea

Neuromuscular Neuromuscular

Muscle weakness, flabbiness, fatigue Weakness, dizziness

Muscle cramps and tenderness Muscle cramps

The Summary Boxes at the end of each section provide a re- Paresthesias Paresthesias

Paralysis (severe hypokalemia) Paralysis (severe hyperkalemia)

view of the main content that has been covered. Use the sum- Central Nervous System Cardiovascular

maries to assure that you have covered and understand what Confusion, depression

Cardiovascular

Electrocardiogram changes

Risk of cardiac arrest with severe hyperkalemia

you have read. Postural hypotension

Predisposition to digitalis toxicity

Electrocardiogram changes

In summary, heart failure occurs when the heart fails to Cardiac dysrhythmias

pump sufficient blood to meet the metabolic needs of body Acid-Base Balance

tissues. The physiology of heart failure reflects an interplay Metabolic alkalosis

between a decrease in cardiac output that accompanies im-

paired function of the failing heart and the compensatory

mechanisms designed to preserve the cardiac reserve.

Compensatory mechanisms that contribute to maintenance CHART 5-2 TNM Classification System

of the cardiac reserve include the Frank-Starling mechanism, T (tumor)

sympathetic nervous system responses, the renin-angiotensin-

aldosterone mechanism, and myocardial hypertrophy. In the Tx Tumor cannot be adequately assessed

failing heart, early decreases in cardiac function may go un- T0 No evidence of primary tumor

noticed because these compensatory mechanisms maintain Tis Carcinoma in situ

the cardiac output. This is called compensated heart failure. T1–4 Progressive increase in tumor size or involvement

Unfortunately, the mechanisms were not intended for long- N (nodes)

term use, and in severe and prolonged heart failure, the

compensatory mechanisms no longer are effective and fur- Nx Regional lymph nodes cannot be assessed

ther impair cardiac function. N0 No evidence of regional node metastasis

Heart failure may be described as high-output or low-out- N 1–3 Increasing involvement of regional lymph nodes

put failure, systolic or diastolic failure, and right-sided or left- M (metastasis)

sided failure. With high-output failure, the function of the

heart may be supernormal but inadequate because of exces- Mx Not assessed

sive metabolic needs, and low-output failure is caused by M0 No distant metastasis

disorders that impair the pumping ability of the heart. With M1 Distant metastasis present, specify sites

systolic dysfunction, there is impaired ejection of blood from

the heart during systole; with diastolic dysfunction, there is

impaired filling of the heart during diastole. Right-sided fail-

ure is characterized by congestion in the peripheral circula-

tion, and left-sided failure by congestion in the pulmonary

circulation.

The manifestations of heart failure include edema, noc-

turia, fatigue and impaired exercise tolerance, cyanosis, signs

ILLUSTRATIONS

of increased sympathetic nervous system activity, and im-

paired gastrointestinal function and malnutrition. In right- The full-color illustrations will help you to build your own

sided failure, there is dependent edema of the lower parts of

the body, engorgement of the liver, and ascites. In left-sided mental image of the content that is being presented. Each

failure, shortness of breath and chronic, nonproductive

cough are common.

drawing has been developed to fully support and build upon

Acute pulmonary edema is a life-threatening condition in the ideas in the text. Some illustrations are used to help you

which the accumulation of fluid in the interstitium of the

lung and alveoli interferes with lung expansion and gas ex- picture the complex interactions of the multiple phenomena

change. It is characterized by extreme breathlessness, crack-

les, frothy sputum, cyanosis, and signs of hypoxemia. In car-

that are involved in the development of a particular disease;

diogenic shock, there is failure to eject blood from the heart, others can help you to visualize normal function or under-

hypotension, inadequate cardiac output, and impaired per-

fusion of peripheral tissues. Mechanical support devices, in- stand the mechanisms whereby the disease processes exert

cluding the intra-aortic balloon pump (for acute failure) and

the VAD, sustain life in persons with severe heart failure.

their effects. In addition, photographs of pathologic processes

Heart transplantation remains the treatment of choice for and lesions provide a realistic view of selected pathologic

many persons with end-stage heart failure.

processes and lesions.

To the Reader xv



Inhalation of

down your answers to the review questions at the end of the

tubercle bacillus chapter. If you are unable to answer a question, reread the rel-

evant section in the chapter. In addition, you will find multiple-

choice questions on the back-of-the-book CD-ROM and on the

Connection site (http://connection.LWW.com/go/porth). Use

these quizzes to test yourself as well.

Primary Secondary

tuberculosis tuberculosis



APPENDICES

Cell-mediated Development of

hypersensitivity cell-mediated Reinfection

response immunity

Your book contains two appendices. Appendix A, “Laboratory

Granulomatous

Values,” provides rapid access to normal values for many lab-

inflammatory

response

Positive skin

test oratory tests, as well as a description of the prefixes, symbols,

and factors (e.g., micro, µ, 10−6) used for describing these val-

Ghon's

Progressive ues. Knowledge of normal values can help you to put abnor-

or disseminated

complex

tuberculosis mal values in context. Appendix B, “Weblinks,” is provided to

help you in obtaining additional information on topics that are

Healed dormant Reactivated of interest to you. The websites in Appendix B will also help

lesion tuberculosis

you to keep abreast of new information that is constantly

■ FIGURE 20-2 ■ Pathogenesis of TB Infection

evolving. For your convenience, these weblinks are also found

on the book’s Connection site.

We hope that this guide has given you a clear picture of how

to use this book. Good luck and enjoy the journey!

MATERIALS FOR REVIEW

Several features have been built into the text to help you verify

your understanding of the material that you have just read.

After you have finished reading and studying the chapter, write