Mechanisms of Cell Injury and Aging

Vocabulary flashcards covering cellular adaptations, mechanisms of cellular injury, intracellular accumulations, modes of cell death (necrosis vs. apoptosis), and cellular aging based on lecture notes.

Cellular Adaptation

The process by which cells adapt to changes in their internal environment by altering their size, number, or cell type, either singly or in combination.

Atrophy

A decrease in cell size caused by decreased work demands or an adverse environment, leading to a lower level of function that reduces oxygen and nutrient needs.

Hypertrophy

An increase in cell size and functional mass resulting from an increased workload, occurring via normal physiological or abnormal pathological mechanisms.

Hyperplasia

An increase in the total number of cells in tissues capable of mitosis, occurring as a controlled process in response to physiological or non-physiological stimuli.

Metaplasia

The replacement of one mature, differentiated cell type by another mature, differentiated cell type that does not typically occur in that tissue, usually induced by chronic irritation and inflammation.

Dysplasia

Deranged or disorderly cell growth characterized by abnormal variations in cell shape, size, and arrangement, which is implicated as a precursor to cancer.

Cellular Injury

A condition that occurs when a cell is unable to maintain homeostasis, which may be reversible (allowing cell recovery) or irreversible (resulting in cell death).

Hypoxia

A lack of oxygen within cells that prevents ATP production, commonly caused by ischemia, respiratory disease, anemia, or reduced oxygen availability.

Ischemia

The interruption or suppression of blood flow to an area, serving as the most common cause of hypoxia.

Hydropic Swelling

An acute, reversible cell swelling (also termed oncosis) caused by intracellular water accumulation due to ATP failure and malfunction of the $\text{Na}^+/\text{K}^+$ pump.

Reperfusion Injury

Cell injury that occurs when blood supply is restored to ischemic tissue, driven by intracellular calcium overload, reactive oxygen species formation, and inflammation.

Reactive Oxygen Species (ROS)

Molecules with unpaired electrons that form or break chemical bonds, causing cellular membrane damage through lipid peroxidation, protein breakdown and misfolding, and DNA damage.

Intracellular Accumulations

The accumulation of normal cellular substances or abnormal endogenous/exogenous materials that cells cannot immediately use or eliminate.

Tay-Sachs Disease

A lysosomal storage disease caused by Hexosaminidase A deficiency, leading to the accumulation of gangliosides in brain nerve cells.

Gaucher's Disease

A lysosomal storage disease caused by lysosomal glucocerebrosidase deficiency, leading to glucocerebroside accumulation in white blood cells, macrophages, oligodendrocytes, and Schwann cells.

Lipofuscin

An endogenous pigment consisting of indigestible residues produced during the normal turnover of cellular structures.

Necrosis

An always pathological form of cell death resulting from severe cell injury, characterized by increased cell volume, plasma membrane breakdown, content leakage, and local tissue inflammation.

Apoptosis

Programmed cell death regulated by intracellular signaling cascades, characterized by cell shrinkage, chromatin condensation, DNA fragmentation, and formation of membrane-bound apoptotic bodies without cellular rupture or inflammation.

Gangrene

A considerable mass of necrotic tissue, categorized into dry, moist/wet, and gas gangrene.

Cellular Aging

The cumulative result of a progressive decline in the proliferative and reparative capacity of cells combined with accumulated molecular and DNA damage from environmental exposures.

Somatic Death

Death of the entire organism, non-definitively characterized by the absence of respiration and heartbeat.