General Principles of Pathology: Cell Adaptation

Vocabulary terms and definitions focusing on the different mechanisms of cellular adaptation and growth as described in general pathology.

Cell Adaptation

The natural response of cells towards internal or external environmental stimuli involving cellular changes in metabolism or growth patterns, which can be structural or functional.

Atrophy

The reduction in size of functioning cells due to a decrease in functional demand, trophic stimuli, or nutrients.

Ischaemia

A restriction of blood flow that serves as a cause of cellular atrophy.

Lipofuscin

A yellow-brown intracellular pigment, also known as brown atrophy, composed of indigestible cell components such as mitochondria and endoplasmic reticulum.

Involution

A form of physiological reduction in organ size that involves the apoptosis of cells.

Apoptosis

A mechanism of cell death affecting single cells scattered in a population of healthy cells; it is a normal physiological process for destroying worn-out or abnormal cells.

Hypertrophy

An increase in the size of functioning cells due to an increase in functional demand or workload; it occurs mainly in tissues where no mitotic division can take place.

Pathologic Hypertrophy

Increase in cell size due to abnormal conditions, such as the thickening of the urinary bladder caused by a urinary outflow obstruction.

Compensatory Hypertrophy

A type of hypertrophy where an organ enlarges to cope with an increased workload, such as the remaining kidney enlarging after a nephrectomy.

Hyperplasia

An increase in the number of functional cells occurring in tissues where cells are capable of mitotic division.

Metaplasia

The change from one mature cell type to another mature cell type, usually in response to chronic irritation and inflammation.

Dysplasia

Disordered development or deranged cell growth of specific tissue resulting in cells that vary in size, shape, and appearance; it is strongly implicated as a precursor of cancer.

Pathological Stimuli

Environmental changes that lie outside an acceptable range of normality.

Reversible Change

Cellular changes where the cell can return to normal if the stimulus is removed.

Irreversible Change

Cellular changes that lead to permanent cellular damage or cell death.