CHAPTER 5 CHAPTER 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 ParticlesPREVENTION AND CONTROLTUMORS 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 ParticlesPREVENTION AND CONTROLTUMORS AND CANCER

Neoplasms Causes of Cancer Pathogenesis of Cancer

INFLAMMATION Inflammatory Response Inflammatory Disease

STUDYING DISEASESTUDYING DISEASEA. 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

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STUDYING DISEASESTUDYING DISEASEB. 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)

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PATHOPHYSIOLOGYPATHOPHYSIOLOGY

A. Mechanisms of disease1. Pathophysiology—the study of

underlying physiological aspects of disease

2. Genetic mechanisms3. Pathogenic organisms and particles4. Tumors and cancer5. Physical and chemical agents6. Autoimmunity7. Inflammation8. Degeneration

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PATHOPHYSIOLOGYPATHOPHYSIOLOGY

B. Risk factors (predisposing conditions)

1. Genetic factors2. Age3. Lifestyle4. Stress5. Environmental factors6. Preexisting conditions

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PATHOGENIC ORGANISMS PATHOGENIC ORGANISMS AND PARTICLESAND 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

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Virus (blue dots)

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PATHOGENIC ORGANISMS PATHOGENIC ORGANISMS AND PARTICLESAND PARTICLES

A. Types of organisms and particles

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PATHOGENIC ORGANISMS PATHOGENIC ORGANISMS AND PARTICLESAND PARTICLES

A. Types of organisms and particles2. Prions (Figure 5-5)

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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 PATHOGENIC ORGANISMS AND PARTICLESAND PARTICLES

A. Types of organisms and particles3. Bacteria (Table 5-2 and Figure 5-6)

a. Tiny cells without nucleib. Secrete toxins, parasitize host cells, or form

coloniesc. 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

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PATHOGENIC ORGANISMS PATHOGENIC ORGANISMS AND PARTICLESAND PARTICLES

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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 particles3. Bacteria

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PATHOGENIC ORGANISMS PATHOGENIC ORGANISMS AND PARTICLESAND PARTICLES

A. Types of organisms and particles4. Fungi (Table 5-3 and Figure 5-8)

a. Simple organisms similar to plants but lacking chlorophyll

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b. Yeasts—small, single-celled fungi

c. Molds—large, multicellular fungi

d. Mycotic infections—often resist treatment

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PATHOGENIC ORGANISMS PATHOGENIC ORGANISMS AND PARTICLESAND PARTICLES

A. Types of organisms and particles5. 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

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PATHOGENIC ORGANISMS PATHOGENIC ORGANISMS AND PARTICLESAND PARTICLES

A. Types of organisms and particles

6. Pathogenic animals (Table 5-5 and Figure 5-12)

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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 PREVENTION AND CONTROLCONTROL

A. Mechanisms of transmission1. Person—to-person contact

a. Can be prevented by educationb. Can be prevented by using aseptic

technique (Table 5-6)2. Environmental contact

a. Can be prevented by avoiding contactb. Can be prevented by safe sanitation

practices3. Opportunistic invasion

a. Can be prevented by avoiding changes in skin and mucous membranes

b. Can be prevented by cleansing of wounds4. Transmission by a vector

a. Can be prevented by reducing the population of vectors and reducing contact with vectors

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PREVENTION AND PREVENTION AND CONTROLCONTROL

B. Other prevention and treatment strategies

1. Vaccination—stimulates immunity

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2. Chemicals—destroy or inhibit pathogens

a. Antibiotics—natural compounds derived from living organisms

b. Synthetic compounds (for example, ACV and efavirenz)

TUMORS AND CANCERTUMORS AND CANCERA. Neoplasms (tumors)—abnormal

growths of cells1. Benign tumors remain localized2. Malignant tumors spread, forming

secondary tumors3. Metastasis—cells leave a primary tumor

and start a secondary tumor at a new location (Figure 5-15)

4. Classification of tumorsa. Benign, epithelial tumors

(1) Papi1loma—finger-like projection(2) Adenoma—glandular tumor(3) Nevus—small, pigmented tumor

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TUMORS AND CANCERTUMORS AND CANCERA. Neoplasms (tumors)—abnormal

growths of cells4. 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

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TUMORS AND CANCERTUMORS AND CANCERB. The causes of cancer—varied and

still not clearly understood1. 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. Aged. Injury—chronic exposure to ite. Viruses

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TUMORS AND CANCERTUMORS AND CANCERC. Pathogenesis of cancer

1. Early detection is important2. Methods of detecting cancers (Figure 5-

16)a. Self-examinationb. 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

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TUMORS AND CANCERTUMORS AND CANCERC. 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. Treatmentsa. Surgeryb. Chemotherapy (chemical therapy)c. Radiation therapy (radiotherapy)d. Laser therapye. Immunotherapyf. New strategies (for example, vaccines)

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INFLAMMATIONINFLAMMATIONA. The inflammatory response—reduces

injury to tissues, thus maintaining homeostasis (Figures 5-17 and 5-18)

1. Signs—redness, heat, swelling, and pain2. 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)

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INFLAMMATIONINFLAMMATION

B. Inflammatory diseases1. 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

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CREDITSCREDITS

All photos and references are taken from:

Thibodeau, Gary, & Patton, Kevin. (2005). The Human body in health & disease. Mosby.

ISBN: 0-323-03161-7

All photos and references are taken from:

Thibodeau, Gary, & Patton, Kevin. (2005). The Human body in health & disease. Mosby.

ISBN: 0-323-03161-7