• Pathology- the study of disease.
• Diseases are usually diagnosed by signs and
• Signs/Symptoms- objective abnormalities that
can be seen or measured by someone other
than the patient.
• Syndrome- a collection of different signs and
symptoms that occur together.
• Acute- signs and symptoms appear suddenly,
persist for a short time and then disappear.
• Chronic- signs and symptoms develop slowly
and last for a long time.
• Subacute- diseases with characteristics
somewhere between acute and chronic.
• Etiology- the study of all factors involved in
causing a disease.
• Idiopathic- diseases with undetermined causes.
• Communicable- diseases that can be transmitted
from one person to another.
• Pathogenesis- a diseases acutal pathern of
• Incubation- “latent” stage or period where no
signs or symptoms of disease are apparent.
• Parasite- an organism that lives in or on another
organism to obtain nutrients.
• Epidemiology- the study of the occurrence,
distribution, and transmission of diseases in
• Endemic- a disease that is native to a local
• Epidemic- a disease that spreads to many
individuals at the same time.
• Pandemics- are epidemics that affect large
• Other than direct causes or disease mechanisms, certain
predisposing conditions may exist that make development of
disease more likely to occur.
1. Genetic Factors- there are several types of genetic factors.
Inherited factors can sometimes put one at a greater risk than
normal for developing disease.
- Example: fair skinned people and melanomas, sickle cell
anemia in African decents.
2. Age- biological and behavioral variations during different life phases
have greater risks for disease.
- Example: middle ear infections in infants.
3. Lifestyle- the way we live and work can put us at risk for some
-Example: People who work outside are more likely to get skin
4. Stress- physical, psychological, and emotional stress can put one at risk for
-Example: high blood pressure, ulcers
5. Environmental factors- factors such as climate and pollution can actually
cause injury or disease. Also some environmental situations simply put us
at risk for getting certain diseases.
-Example: parasites in tropical climates
6. Microorganisms- different types of pathological organisms (viruses and
bacteria) are now suspected of being “infectious cofactors” in the
development of certain diseases.
-Example: link between hepatitis B and liver cancer.
7. Preexisting conditions- a preexisting condition can adversly affect our
capacity to defend ourselves against an entirely different condition or
-Example: people with AIDS have a suppressed immune system.
Mechanisms for Disease
• Pathophysiology- the organized study of underlying physiological
processes associated with disease.
• Basic mechanisms of disease- disturbances to homeostasis and the
1. Genetic Mechanisms- altered or mutated genes can cause
abnormal proteins to be made. These abnormal proteins do not
perform their intended function resulting in a lack of essential
2. Pathogenic organisms- many important disorders are caused by
pathogenic organisms or particles that damage the body in some
- Viruses -Protozoa
-Bacteria -Pathogenic animals
Mechanisms of Disease
3. Tumors and Cancer- abnormal tissue growth
can cause various pathological disturbances.
4. Physical and Chemical Agents
5. Malnurition- insufficient and imbalanced
intake of nutrients causes various disease.
6. Autoimmunity- some diseases result from the
immune system attacking one’s own body
Mechanisms of Disease
7. Inflammation- the body often responds to
disturbances with the inflammatory response. This is a
normal mechanism that usually speeds recovery from
an infection or injury. When the response occurs in an
inappropriate time or for a prolonged amount of time
then tissue damage can occur.
8. Degeneration- by means of many still unknown
processes, tissues sometimes break apart or
• Communication, Control and Integration
– Nervous: Brain, Spinal Cord, Nerves, Sensory
– Endocrine: Pituitary gland, adrenals, pancreas,
thyroid, other glands
• Support and Movement
– Integumentary: Skin
– Skeletal: Bones, Ligaments
– Muscular: Skeletal muscles, tendons