Cell Injury and Cell Death: Part 2

Apoptosis

A pathway of cell death, a regulated suicide program involving the activation of intrinsic enzymes that degrade the cells’ own nuclear DNA, and nuclear and cytoplasmic proteins.

Apoptotic bodies

Fragments of an apoptotic cell which contain portions of the cytoplasm and nucleus.

Chromatin condensation

The most characteristic morphological feature of apoptosis.

Caspases

Enzymes activated during apoptosis that cleave proteins after aspartic residues.

Intrinsic (mitochondrial) pathway

The major mechanism of apoptosis in all mammalian cells, resulting from increased permeability of the mitochondrial outer membrane.

Extrinsic (death-receptor initiated) pathway

A pathway of apoptosis initiated by the engagement of plasma membrane death receptors (members of the TNF receptor family like TNFR1 and Fas/CD95).

Necroptosis

A hybrid form of cell death that shares aspects of both necrosis and apoptosis; also known as programmed necrosis and caspase-independent programmed cell death.

Pyroptosis

A form of programmed cell death accompanied by the release of fever-inducing cytokine IL-1 and bearing some biochemical similarities with apoptosis.

Autophagy

A process in which a cell eats its own contents, delivering cytoplasmic materials to the lysosome for degradation.

Intracellular Accumulations

One of the manifestations of metabolic derangements in cells, where substances accumulate within the cytoplasm, organelles, or nucleus.

Steatosis (fatty change)

Abnormal accumulations of triglycerides within parenchymal cells.

Hyaline change

An alteration within cells or in the extracellular space that gives a homogenous, glassy, pink appearance.

Lipofuscin

An insoluble endogenous pigment, also known as lipochrome or "wear-and-tear" pigment.

Melanin

The only endogenous brown-black pigment.

Hemosiderin

A hemoglobin-derived, golden yellow-to-brown endogenous pigment.

Dystrophic calcification

Abnormal tissue deposition of calcium salts that occurs locally in dying tissues despite normal serum calcium levels.

Metastatic calcification

Abnormal tissue deposition of calcium salts that may occur in normal tissues whenever there is hypercalcemia.

Cellular aging

The result of a progressive decline in cellular function and viability, caused by genetic abnormalities and the accumulation of cellular and molecular damage.

BCL2 proteins

Proteins that control the release of mitochondrial pro-apoptotic proteins in the intrinsic (mitochondrial) pathway of apoptosis.

TNFR1 (Type 1 TNF receptor)

A well-known plasma membrane death receptor involved in the extrinsic (death-receptor initiated) pathway of apoptosis.

Fas (CD95)

A death receptor related to TNFR1, involved in the extrinsic (death-receptor initiated) pathway of apoptosis.

FLIP protein

A protein that inhibits the extrinsic (death-receptor initiated) pathway of apoptosis.

Phosphatidylserine

An "eat me" signal exposed on the surface of apoptotic cells to promote phagocytosis.

Necrosome

A key complex formed during the induction of necroptosis, involving RIP1 and RIP3.

Chaperone-mediated autophagy

One of the three types of autophagy, where specific proteins are directly translocated into lysosomes for degradation via chaperones.

Macroautophagy

A type of autophagy involving the formation of an autophagosome that engulfs cytoplasmic material and fuses with a lysosome for degradation.

Anthracosis

Blackening of the tissues, typically of the lungs, due to the accumulation of carbon (coal dust).

Alpha-1 antitrypsin deficiency

A genetic liver disorder where mutant alpha-1 antitrypsin protein accumulates inside the endoplasmic reticulum as hyaline globules due to defective transport.

Russell bodies

Round cherry-red inclusions seen in plasma cells, representing intracellular accumulations of proteins.

Mallory hyaline

Intracellular accumulations consisting of keratin intermediate filaments.

Hypercalcemia

Abnormally high serum calcium levels, a primary cause of metastatic calcification.