chapter three: Mechanism of Disease and Pathogenic Organisms

What is pathology?

the scientific study of disease 

What is disease?

an abnormality in body function that threatens health

What is etiology?

The cause of disease

What is epidemiology?

The study of disease occurrence, distribution, and transmission in populations

What is a diagnosis?

Identifying a disease based on signs and symptoms

What is a prognosis?

Predicted outcome of a disease

What are the patterns of disease?

Endemic, epidemic, pandemic, sporadic, acute disease, and chronic disease

What is an endemic?

Regularly found in a particular area or a population

What is an epidemic?

Sudden, widespread outbreak in a region

What is a pandemic?

Global outbreak of a disease

What is sporadic?

Occasional cases in isolated areas

What is an acute disease?

rapid and onset, short duration (like the flu)

What is a chronic disease?

long-lasting, may be lifelong (like diabetes)

What are the mechanisms of disease?

genetic mechanisms, pathogenic organisms, tumors and cancers, physical & mechanical agents, malnutrition, autoimmunity, inflammation and degeneration

What is genetic mechanisms?

mutations or inherited traits leading to disorders such as cystic fibrosis and sickle cell anemia

What are pathogenic organisms?

bacteria, viruses, fungi, parasites that invade and damage tissues

What are tumors and cancers?

abnormal cell growth disrupting tissue function

What are physical & chemical agents?

toxins, radiation, extreme heat/cold causing injury

What is malnutrition?

lack of proper nutrients leading to diseases such as scurvy from vitamin C deficiency

What is autoimmunity?

when the immune system attacks the body’s own cells, like lupus and arthritis

What is inflammation?

a protective response that may cause damage if excessive or chronic

What is degeneration?

breakdown of tissues due to aging or wear-and-tear

What are risk factors associated with diseases with examples?

1. Genetic predisposition: inherited risk

2. Age: certain diseases more common in young or elderly.

3. Lifestyle: poor diet, smoking, lack of exercise, stress.

4. Stress: can weaken immune defenses

5. Environmental factors: pollution, toxins, climate.

6. Pre-exisiting conditions: one disease increasing risk for another (e.g., obesity and diabetes).

What are the six categories of pathogenic organisms?

Viruses, bacteria, fungi, protozoa, pathogenic animals (metazoa) and prions

What are viruses?

tiny particles of DNA/RNA inside a protein coat; hijack host cells to reproduce, often destroying them (e.g., flu, HIV, COVID-19).

What is bacteria?

single-celled organisms; some produce toxins or invade tissues (e.g., strep throat, tuberculosis).

What is fungi?

include yeasts and molds; cause infections often on skin or mucous membranes (e.g., ringworm, yeast infections).

What is protoza?

single-celled animal-like organisms; often spread through contaminated water/food (e.g., malaria, giardiasis).

What are pathogenic animals?

larger, multicellular organisms such as worms and insects; can cause disease directly or transmit pathogens (e.g., tapeworms, mosquitoes spreading malaria).

What are prions?

misfolded proteins that cause abnormal folding of normal proteins in the brain; lead to neurodegenerative diseases (e.g., mad cow disease, Creutzfeldt-Jakob disease).