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Pathology

The causes of disease and the changes in cells, tissues, and organs associated with the development of disease.

Etiology

The origin of a disease, including the underlying causes and modifying factors.

Pathogenesis

Steps in disease development.

Homeostasis

The steady state of internal physical and chemical conditions; indicates that there is NO STRESS.

Adaptation

A new steady state that preserves viability and function, occurring when a cell becomes stressed.

Reversible Injury

Injury where the cell can revert to homeostasis upon removal of stress.

Irreversible Injury

Injury that leads to cell death, unable to be reversed due to severe and progressive stress.

Reactive Oxygen Species (ROS)

Unstable molecules that damage DNA, proteins, and membranes.

Oxidative Stress

Cellular damage caused by the accumulation of reactive oxygen species (ROS).

Unfolded Protein Response (UPR)

A cellular response to misfolded proteins that increases chaperone expression, reduces protein synthesis, and promotes degradation.

Ubiquitin Proteasome System (UPS)

The main system the cell uses to clear misfolded proteins, involving tagging them for degradation.

Mitochondrial Dysfunction

A condition where mitochondria fail to produce adequate ATP, leading to cell injury.

Atrophy

A decrease in cell and organ size due to pathological and physiologic causes.

Hypertrophy

An increase in cell and organ size in response to increased workload.

Hyperplasia

An increase in cell numbers in response to hormones and growth factors.

Metaplasia

A change in one adult cell type to another adult cell type, reprogramming stem cells.

Necrosis

A form of cell death characterized by irreversible damage and disintegration of cellular components.

Apoptosis

A programmed pathway by which cells degrade their own nuclear DNA and proteins, leading to cellular fragmentation.

Ischemia

A condition where blood flow is obstructed, preventing oxygen and nutrients from reaching tissues.

Hypoxia

A condition where oxygen delivery is reduced, but blood flow is maintained.

Dystrophic Calcification

Calcium deposits in dead/damaged tissue.

Metastatic Calcification

Calcium deposits in normal tissues due to systemic hypercalcemia.

p53

A tumor suppressor gene that helps prevent cancer by inducing apoptosis in the case of excessive DNA damage.