Cellular Adaptation, Injury, and Genetic Defects

Practice flashcards covering types of cell populations, mechanisms of cellular adaptation, types of cell injury, intracellular accumulations, and genetic/congenital defects.

Labile cells

A continuously renewing cell population.

Stable cells

A potentially expanding cell population.

Permanent cells

A static cell population.

Atrophy

The shrinkage of a cell or organ due to the loss of organelles; a reversible restructuring of activities to facilitate survival under conditions of diminished use.

Physiological atrophy

The normal loss of endocrine stimulation.

Pathological atrophy

Atrophy caused by diminished blood supply, inadequate nutrition, loss of innervation, abnormal loss of endocrine stimulation, or decreased workload.

Hypertrophy

An increase in cell size and functional capacity due to an increase in the production and number of intracellular organelles.

Hyperplasia

An increase in the size of an organ or tissue due to an increase in the number of cells.

Metaplasia

A change in which one terminally differentiated cell type is replaced by another terminally differentiated cell type, often as a response to persistent injury or irritation.

Dysplasia

The disordered growth and maturation of the cellular components of a tissue, characterized by a loss of cell uniformity and architectural orientation.

Steatosis

The accumulation of triglycerides within parenchymal cells, most commonly involving the liver; also known as fatty change.

Hydropic change

The increase in water accumulation within parenchymal cells, most commonly caused by a loss of $ATP$ resulting in the failure of the sodium-potassium $ATPase$ pump.

Hemosiderin

An iron pigment accumulation within parenchymal cells and the interstitium, appearing as golden brown granules derived from hemoglobin/$RBC$ breakdown.

Lipofuscin

Known as the wear and tear pigment, it is an undigestable mixture of lipids and proteins resulting from oxidative stress that increases with age.

Xanthomas

Disorders characterized by the accumulation of cholesterol.

Hypoxia

Cell injury due to ischemia or the decreased $O_2$ carrying capacity of the blood.

Pyknosis

A nuclear change characterized by a nucleus that is small, shrunken, and dark, indicating the cessation of $DNA$ transcription.

Karryorrhexis

A process of necrosis where the nucleus becomes fragmented into several small pieces.

Karyolysis

The complete dissolution of the nucleus during necrosis, leaving the cell as a mass of partly denatured protein.

Fenton Reaction

A reaction where $Fe^{2+}$ catalyzes the formation of free radicals from hydrogen peroxide ($H_2O_2$).

Trisomy $21$ (Down Syndrome)

A chromosomal abnormality characterized by decreased $IQ$, a simian crease, a protruding tongue, epicanthic folds, and Tetrology of Fallot.

Trisomy $18$ (Edwards Syndrome)

A chromosomal abnormality featuring severe cardiac malformations, rocker-bottom feet, clenched hands, and low-set ears, where the majority die within $1\,year$.

Trisomy $13$ (Patau Syndrome)

A condition marked by severe cognitive and growth delay, cleft lip and palate, and nervous system and cardiac malformations.

Cri-du-chat syndrome

A $5p-$ syndrome caused by a deletion on chromosome $5$, characterized by an infant's high-pitched cry, intellectual disability, microcephaly, and hypotonia.

Kleinfelter Syndrome

A condition ($47, XXY$) where males possess more than one $X$ chromosome, leading to hypogonadism, infertility, a tall/thin stature, and gynecomastia.

Turner Syndrome

A condition ($45, X$) in females characterized by primary amenorrhea, sterility, short stature, and a webbed neck.

Lesch–Nyhan syndrome

An $X$-linked deficiency of $HGPRT$ causing uric acid accumulation, poor muscle control, and self-mutilating behaviors like lip and finger biting.

Phenylketonuria (PKU)

An autosomal recessive deficiency of phenylalanine hydroxylase leading to mental deterioration, fair skin/blond hair, and a mousy or musty odor.

Alkaptonuria (Ochronosis)

A defect in the enzyme homogentisate $1,2$-dioxygenase where urine demonstrates oxygenation of homogentisic acid; may lead to degenerative arthropathy.

Dystrophic calcification

The abnormal deposition of calcium salts in dead (necrotic) or non-viable tissue.

Metastatic calcification

The deposition of calcium in normal tissues due to hypercalcemia.