C HAPTER 5

AFTER YOU HAVE COMPLETED THIS CHAPTER, YOU SHOULD BE ABLE TO: 1. Define the terms health and disease. 2. List and describe the basic mechanisms of disease and risk factors associated with disease. 3. List and describe five categories of pathogenic organisms and explain how they cause disease. 4. Distinguish between the terms benign and malignant as they apply to tumors. 5. Describe the pathogenesis of cancer. 6. Outline the events ct the inflammatory response and explain its role in disease.

In this presentation we will discuss the following: STUDYING DISEASE  Disease Terminology  Patterns of Disease PATHOPHYSIOLOGY  Mechanisms of Disease  Risk Factors PATHOGENIC ORGANISMS AND PARTICLES  Types of Organisms and Particles PREVENTION AND CONTROL TUMORS AND CANCER  Neoplasms  Causes of Cancer  Pathogenesis of Cancer INFLAMMATION  Inflammatory Response  Inflammatory Disease STUDYING DISEASE  Disease Terminology  Patterns of Disease PATHOPHYSIOLOGY  Mechanisms of Disease  Risk Factors PATHOGENIC ORGANISMS AND PARTICLES  Types of Organisms and Particles PREVENTION AND CONTROL TUMORS AND CANCER  Neoplasms  Causes of Cancer  Pathogenesis of Cancer INFLAMMATION  Inflammatory Response  Inflammatory Disease

STUDYING DISEASE A. Disease terminology 1. Health—physical, mental, and social wellbeing— not merely the absence of disease 2. Disease-—an abnormality in body function that threatens health 3. Etiology—the study of the factors that cause a disease 4. Idiopathic—refers to a disease with an unknown cause 5. Signs and symptoms—the objective and subjective abnormalities associated with a disease 6. Pathogenesis—the pattern of a disease’s development Page(s)

STUDYING DISEASE B. Patterns of disease 1. Epidemiology is the study of occurrence, distribution, and transmission of diseases in human populations 2. Endemic diseases are native to a local region 3. Epidemics occur when a disease affects many people at the same time 4. Pandemics are widespread, perhaps global, epidemics 5. Discovering the cause of a disease is difficult because many factors affect disease transmission 6. Disease can be fought through prevention and therapy (treatment) Page(s)

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PATHOPHYSIOLOGY A. Mechanisms of disease 1. Pathophysiology—the study of underlying physiological aspects of disease 2. Genetic mechanisms 3. Pathogenic organisms and particles 4. Tumors and cancer 5. Physical and chemical agents 6. Autoimmunity 7. Inflammation 8. Degeneration Page(s)

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PATHOPHYSIOLOGY B. Risk factors (predisposing conditions) 1. Genetic factors 2. Age 3. Lifestyle 4. Stress 5. Environmental factors 6. Preexisting conditions Page(s)

PATHOGENIC ORGANISMS AND PARTICLES A. Types of organisms and particles 1. Viruses (Table 5-1) a. Microscopic, intracellular parasites that consist of a nucleic acid core with a protein coat b. Invade host cells and pirate organelles and raw materials c. May be transmitted directly from human to human, or may be transmitted indirectly through a biting insect d. Classified by shape, nucleic acid type, and method of reproduction Page(s) Virus (blue dots)

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PATHOGENIC ORGANISMS AND PARTICLES A. Types of organisms and particles Page(s)

PATHOGENIC ORGANISMS AND PARTICLES A. Types of organisms and particles 2. Prions (Figure 5-5) Page(s) a. Pathogenic protein molecules b. Convert normal proteins to abnormal proteins, causing abnormal functions that produce disease; may be passed on to offspring c. Cause rare, degenerative disorders of the nervous system such as BSE (bovine spongiform encephalopathy—”Mad Cow Disease”) and vCJD (variant Creutzfeldt-Jakob disease)

PATHOGENIC ORGANISMS AND PARTICLES A. Types of organisms and particles 3. Bacteria (Table 5-2 and Figure 5-6) a. Tiny cells without nuclei b. Secrete toxins, parasitize host cells, or form colonies c. Classification (1) By function (a) Aerobic—require oxygen (b) Anaerobic—require no oxygen (2) By staining properties (composition of cell wall) (a) Gram-positive (b) Gram-negative (3) By shape and size (a) Bacilli—rod-shaped cells (b) Cocci—round cells (c) Curved or spiral rods (d) Small bacteria—obligate parasites Page(s)

PATHOGENIC ORGANISMS AND PARTICLES Page(s) d. Spores—nonreproducing forms of bacteria that resist unfavorable environmental conditions e. Archaea are similar to bacteria but with a different chemical makeup and different metabolism (allowing them to survive harsh conditions) and do not infect humans A. Types of organisms and particles 3. Bacteria

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PATHOGENIC ORGANISMS AND PARTICLES A. Types of organisms and particles 4. Fungi (Table 5-3 and Figure 5-8) a. Simple organisms similar to plants but lacking chlorophyll Page(s) b. Yeasts—small, single-celled fungi c. Molds—large, multicellular fungi d. Mycotic infections— often resist treatment

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PATHOGENIC ORGANISMS AND PARTICLES A. Types of organisms and particles 5. Protozoa (Table 5-4 and Figure 5-10) a. Large, one-celled organisms having organized nuclei b. May infest human fluids and parasitize or destroy cells c. Major groups (1) Amoebas—possess pseudopodia (2) Flagellates—possess flagella (3) Ciliates—possess cilia (4) Sporozoa (coccidia)—enter cells during one phase of a two-part life cycle; borne by vectors (transmitters) during the other phase Page(s)

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PATHOGENIC ORGANISMS AND PARTICLES A. Types of organisms and particles 6. Pathogenic animals (Table 5-5 and Figure 5-12) Page(s) a. Large, complex multicellular organisms b. Parasitize or otherwise damage human tissues or organs c. Major groups (1) Nematodes—roundworms (2) Platyhelminths—flatworms and flukes (3) Arthropods (a) Parasitic mites, ticks, lice, fleas (b) Biting or stinging wasps, bees, mosquitoes, spiders (c) Are often vectors of disease

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PREVENTION AND CONTROL A. Mechanisms of transmission 1. Person—to-person contact a. Can be prevented by education b. Can be prevented by using aseptic technique (Table 5-6) 2. Environmental contact a. Can be prevented by avoiding contact b. Can be prevented by safe sanitation practices 3. Opportunistic invasion a. Can be prevented by avoiding changes in skin and mucous membranes b. Can be prevented by cleansing of wounds 4. Transmission by a vector a. Can be prevented by reducing the population of vectors and reducing contact with vectors Page(s)

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PREVENTION AND CONTROL B. Other prevention and treatment strategies 1. Vaccination—stimulates immunity Page(s) 113, Chemicals—destroy or inhibit pathogens a. Antibiotics—natural compounds derived from living organisms b. Synthetic compounds (for example, ACV and efavirenz)

TUMORS AND CANCER A. Neoplasms (tumors)—abnormal growths of cells 1. Benign tumors remain localized 2. Malignant tumors spread, forming secondary tumors 3. Metastasis—cells leave a primary tumor and start a secondary tumor at a new location (Figure 5-15) 4. Classification of tumors a. Benign, epithelial tumors (1) Papi1loma—finger-like projection (2) Adenoma—glandular tumor (3) Nevus—small, pigmented tumor Page(s)

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TUMORS AND CANCER A.Neoplasms (tumors)—abnormal growths of cells 4. Classification of tumors b. Benign, connective tissue tumors (1) Lipoma—adipose (fat) tumor (2) Osteoma—bone tumor (3) Chondroma—cartilage tumor c. Carcinomas (malignant epithelial tumors) (1) Melanoma—involves melanocytes (2) Adenocarcinoma—glandular cancer d. Sarcomas (connective tissue cancers) (1) Lymphoma—lymphatic cancer (2) Osteosarcoma—bone cancer (3) Myeloma—bone marrow tumor (4) Fibrosarcoma—cancer of fibrous tissue Page(s)

TUMORS AND CANCER B. The causes of cancer—varied and still not clearly understood 1. Cancer involves hyperplasia (growth of too many cells) and anaplasia (development of undifferentiated cells) 2. Factors known to play a role in causing cancer a. Genetic factors (for example, oncogenes— cancer genes) b. Carcinogens—chemicals that alter genetic activity c. Age d. Injury—chronic exposure to it e. Viruses Page(s)

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TUMORS AND CANCER C. Pathogenesis of cancer 1. Early detection is important 2. Methods of detecting cancers (Figure 5-16) a. Self-examination b. Diagnostic imaging—radiography (for example, mammogram and CT scan), magnetic resonance imaging (MRI), ultrasonography c. Biopsy (for example, Pap smear) d. Blood tests 3. Staging—classifying tumors by size and extent of spread 4. Grading-assessing the likely pattern of a tumor’s development Page(s)

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TUMORS AND CANCER C. Pathogenesis of cancer 5. Cachexia—syndrome including appetite loss, weight loss, and general weakness 6. Causes of death by cancer—secondary infections, organ failure, hemorrhage, and undetermined factors 7. Treatments a. Surgery b. Chemotherapy (chemical therapy) c. Radiation therapy (radiotherapy) d. Laser therapy e. Immunotherapy f. New strategies (for example, vaccines) Page(s)

INFLAMMATION A. The inflammatory response—reduces injury to tissues, thus maintaining homeostasis (Figures 5-17 and 5-18) 1. Signs—redness, heat, swelling, and pain 2. Inflammation mediators (histamine, prostaglandins, and kinins) a. Some cause blood vessels to dilate, increasing blood volume (redness and heat)—white blood cells travel quickly to injury site b. Some increase blood vessel permeability (causing swelling or edema and pain)—white blood cells move easily out of vessels, irritant is diluted, and exudate accumulates c. Some attract white blood cells to injury site (chemotaxis) Page(s)

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INFLAMMATION B. Inflammatory diseases 1. Inflammation can be local or systemic (body- wide) 2. Fever—high body temperature caused by a resetting of the body’s "thermostat"— destroys pathogens and enhances immunity 3. Chronic inflammation can constitute a disease itself because its causes damage to tissues Page(s) 137

C REDITS All photos and references are taken from: Thibodeau, Gary, & Patton, Kevin. (2005). The Human body in health & disease. Mosby. ISBN: All photos and references are taken from: Thibodeau, Gary, & Patton, Kevin. (2005). The Human body in health & disease. Mosby. ISBN: