Disease

Chapter Contents

Infectious Diseases Responses to Disease Neoplasia

Word Parts Pertaining to Disease Chapter Review Case Studies Answer Section

Objectives

After study of this chapter you should be able to:

1. List the major categories of diseases.

2. Compare the common types of infectious organisms, and list some diseases caused by each.

3. Define and give examples of neoplasia.

4. Identify and use word parts pertaining to diseases.

5. Define the major terms describing types of diseases.

6. List and define the major manifestations of diseases.

7. Analyze the disease terminology in several case studies.

A disease is any alteration from the normal structure or function of any part of the body. Diseases can be grouped into a number of different but often overlapping categories. These include:

• Infectious diseases—caused by microorganisms and other parasites that live at the expense of another organism. Any disease-causing organism is described as a pathogen.

• Degenerative diseases—resulting from wear and tear, aging, or trauma (injury) that can result in a lesion (wound) and perhaps necrosis (death) of tissue. Common examples include arthritis, cardiovascular problems, and certain respiratory disorders such as emphysema. Structural malformations such as congenital malformations, prolapse (dropping), or hernia (rupture) may also result in degenerative changes.

• Neoplasia—abnormal and uncontrolled growth of tissue.

• Immune disorders—failures of the immune system, allergies, and autoimmune diseases, in which the body makes antibodies to its own tissues, fall into this category. (Immune disorders are discussed in more detail in Chapter 10.)

• Metabolic disorders—resulting from lack of enzymes or other factors needed for cellular functions. Many hereditary disorders fall into this category. Malnutrition caused by inadequate intake of nutrients or inability of the body to absorb and use nutrients also upsets metabolism. (Metabolic disorders are discussed in more detail in Chapter 12, and hereditary disorders are discussed in Chapter 15.)

• Hormonal disorders—caused by underproduction or overproduction of hormones or by inability of the hormones to function properly. One example is diabetes mellitus. (Hormonal disorders are discussed in more detail in Chapter 16.)

• Mental and emotional disorders—disorders that affect the mind and adaptation of an individual to his or her environment. (Behavioral disorders are discussed in more detail in Chapter 17.)

The cause of a disease is its etiology (e-te-OL-o-je), although many diseases have multiple interacting causes. An acute disease is sudden and severe and of short duration. A chronic disease is of long duration and progresses slowly.

box 6-1 Name That Disease

Diseases get their names in a variety of ways. Some are named for the places where they were first found, such as Lyme disease for Lyme, Connecticut; West Nile disease and Rift Valley fever for places in Africa; and hantavirus fever for a river in Korea. Others are named for people who first described them, such as Cooley anemia; Crohn disease, an inflammatory bowel disease; and Hodgkin disease of the lymphatic system.

Many diseases are named on the basis of the symptoms they cause. Tuberculosis causes small lesions known as tubercles in the lungs and other tissues. Skin anthrax produces lesions that turn black, and its name comes from the same root as anthracite coal. In sickle cell anemia, red blood cells become distorted into a crescent shape when they give up oxygen. Having lost their smooth, round form, the cells jumble together, blocking small blood vessels and depriving tissues of oxygen.

Bubonic plague causes painful and enlarged lymph nodes called buboes. Lupus erythemato-sus, a systemic autoimmune disorder, is named for the Latin term for wolf because the red rash that may form on the face of people with this disease gives them a wolf-like appearance. Yellow fever, scarlet fever, and rubella (German measles) are named for colors associated with the pathology of these diseases.

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Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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