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					                                                                                        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 <3.5 mEq/L                             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

				
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