Pathology BIOMED EXAM 1

Pathology

Scientific study of disease

Disease

Abnormal condition disrupting normal structure/function

Disease sequence

Etiology → Pathogenesis → Lesions → Clinical outcome

Etiology

Cause/origin of disease

Pathogenesis

Mechanism/sequence by which disease develops

Lesion

Structural/morphologic change

Clinical outcome

Clinical manifestations of disease

Genetic etiology

Inherited or acquired mutations

Environmental etiology

Hypoxia, smoking, trauma, radiation, toxins, nutritional imbalance

Infectious etiology

Viruses, bacteria, fungi, parasites

Iatrogenic etiology

Unintentionally caused by medical treatment/intervention, including ADRs

Pathology vs. pharmacology

Pathology explains the disease; pharmacology explains how drugs modify it

Sign

Objective, observable/measurable finding (BP 160/100, measured fever)

Symptom

Subjective, patient-reported (headache, nausea, fatigue)

Syndrome

Recognizable group of signs and symptoms occurring together

Why are signs/symptoms useful?

Help diagnose disease, select/monitor treatment, and detect ADRs

Cellular adaptation

Altered form/function that allows a cell to survive continued stress

Atrophy

↓ cell size (e.g., disuse, aging)

Hypertrophy

↑ cell size (e.g., increased workload); occurs when cells have limited ability to divide

Hyperplasia

↑ cell number (e.g., hormonal stimulation); occurs in cells capable of replication

Metaplasia

Change in mature cell type (e.g., chronic irritation); generally reversible but can reduce function and progress toward dysplasia

Cell injury

Occurs when stress exceeds the cell's adaptive ability

Important targets of cell injury

Membranes (barrier/transport loss), mitochondria (↓ ATP), DNA (altered genetic info), proteins (structure/enzymes/receptors), cytoskeleton (structure/movement)

Factors determining severity of injury

Type, dose, and duration of insult; cell type, health, and adaptability

Reversible injury

Stress removed → cell may recover; cellular swelling and fatty changes may occur

Irreversible injury

Severe membrane/mitochondrial damage, loss of cellular contents, ↓ ATP; ultimately cell death

Reactive oxygen species (ROS)

Highly reactive molecules/free radicals; normally controlled by antioxidants

Oxidative stress

ROS production exceeds antioxidant defenses; damages membrane lipids, proteins, and DNA

Necrosis

Always pathologic; irreversible external injury; membrane loses integrity; contents leak; causes inflammation

Apoptosis

Programmed cell death (physiologic or pathologic); membrane stays intact; contents contained/removed; no significant inflammation

Progression of cell stress to death

Normal cell → Stress → Adaptation → Reversible injury → Irreversible injury → Cell death

Cellular changes vs. clinical signs

Cellular changes can occur before signs and symptoms become clinically apparent