1. Human Anatomy/Physiology
Chapter 4 – Mechanisms of Disease

2. Disease Terminology Health disease Pathology Pathogenesis
Physical, mental, and social well-being—not merely the absence of disease
disease
An abnormality in body function that threatens health
Pathology
Study of disease
Pathogenesis
The pattern of a disease’s development

3. Disease Terminology Etiology Idiopathic Symptoms Syndrome
the study of the factors that cause a disease
Idiopathic
Refers to a disease with an unknown cause
Symptoms
The objective and subjective abnormalities associated with a disease
Syndrome
Collection of different signs and symptoms, usually with a common cause, that presents a clear picture of a pathological condition.

4. Disease Terminology Acute Chronic Incubation Convalescence Remission
Signs and symptoms appear suddenly, persist for a short time, then disappear
Chronic
Diseases that develop slowly and last for a long time (perhaps for life)
Incubation
Latent (hidden) stage of a disease
Convalescence
recovery
Remission
Reversal of a chronic disease

5. Patterns of Disease Epidemiology Endemic diseases Epidemic Pandemic
Study of occurrence, distribution, and transmission of diseases in human populations
Endemic diseases
Native to a local population
Epidemic
Occurs when a disease affects many people at the same time
Pandemic
Widespread, perhaps global, epidemic

6. Patterns of Disease
Discovering the cause of a disease is difficult because many factors affect disease transmission
Disease can be fought through prevention and therapy (treatment)

7. Mechanisms of Disease Pathophysiology Genetic Mechanisms
Study of underlying physiological aspects of disease
Genetic Mechanisms
Pathogenic organisms
Tumors and cancer
Physical and chemical agents
malnutrition
Autoimmunity
Inflammation
degeneration

8. Risk Factors (predisposing conditions)
Genetic factors
Age
Lifestyle
Stress
Environmental factors
Preexisting conditions

9. Pathogenic Organisms Bacteria
Tiny cells without a nucleus (prokaryotic)
Secretes poisons (toxins) that damage normal cells and tissues
Form colonies in the body that disrupt normal body functions

10. Pathogenic Organisms Classifying Bacteria Oxygen requirements
Aerobic (needs oxygen)
Anaerobic (doesn’t need oxygen)
Staining (how cell wall accepts staining)
Gram positive (accepts stain)
Gram negative (does not accept stain
Certain antibiotics work for certain cell walls

11. Pathogenic Organisms Classifying bacteria (continued) Shape
Rod-shaped (bacilli/bacillus)
Round-shaped (cocci/coccus)
Spiral shaped (spirillum/spirilla)

12. Pathogenic Organisms
Some bacteria produce spores (endospores) that are resistant to chemicals, heat, and dry conditions

13. Pathogenic Organisms
Some bacteria have an ability to change genetically and make themselves resistant to certain antibiotics.
This can make treatment difficult.
MRSA (methicillin resistant Staphylococcus aureus)

14. Pathogenic Organisms Fungi
Simple organisms similar to plants but without chlorophyll
Parasitize tissue on or near skin or mucus membranes
Can be single-celled (yeasts) or multicelled (molds)

15. Pathogenic Organisms Examples of fungal infections:
Yeast cells infect membranes all over the body
Athlete’s foot
ringworm

16. Pathogenic Organisms Protozoa One-celled organisms that have a nucleus
Cause disease by being parasites
Major groups:
Amoebas
Flagellates
Ciliates
Sporozoa

17. Pathogenic Organisms Pathogenic Animals Called Metazoa
Cause disease by acting like a parasite
An organism that spreads disease to other organisms is called a vector

18. Pathogenic Organisms Major groups of pathogenic animals
Nematodes (roundworms)
Transmit disease through foods or biting insects
Platyhelminths (flatwroms)
Tapeworm
Arthropods
Ticks, mites, lice, fleas, stinging bees, wasps, spiders

19. Pathogenic Organisms Virus
Intracellular parasites made of genetic material (DNA or RNA)
Living or nonliving?
Invade cells and inject genetic material
Some symptoms show up immediately and some don’t for many years

20. Pathogenic Organisms Virus (continued) Very small
200 can fit on a period on a typed page
Examples of viral diseases
Polio
AIDS
Cold
Flu
Herpes
rabies