Pathology Terms

Hypertrophy

increased size of cells

Hyperplasia

non-neoplastic increase in the number of cells in an organ or tissue

Atrophy

reduced size of cells or organs

Metaplasia

conversion of one differentiated cell type to another

Dysplasia (cellular response to injury)

disordered growth and maturation of the cellular components of a tissue. May be a precursor to malignant neoplasia.

Neoplasia

autonomous growth of cells that have escaped normal regulation of cell proliferation

Benign neoplasia

autonomous growth of cells that remains localized

Malignant neoplasia

autonomous growth of cells that spreads or is capable of spreading to different sites (metastasis). Also known as cancer.

Apoptosis

cell death caused by activation of internal molecular pathways. Can be physiological or pathological.

Necrosis

cell death caused by pathological lethal injury that often originates outside the cell

Coagulative necrosis

nuclei disappear (karyolysis) and cytoplasm becomes more homogeneous (and often more acidophilic), resulting in residual ghosts of cells with no nuclei

Pyknosis

process occurring in apoptotic cells in which the nucleus becomes smaller and stains deeply basophilic because of chromatin clumping (hyperchromatic)

Karyorrhexis

process occurring in apoptotic cells in which the pyknotic nucleus breaks up into many smaller fragments

Karyolysis

process occurring in apoptotic cells in which the nucleus may be extruded from the cell or have progressive loss of chromatin staining, resulting in the disappearance of the nucleus

Liquifactive necrosis

rapid dissolution of cells that liquefies the necrotic tissue. Usually caused by intense localized infiltration of neutrophils at sites of severe acute inflammation.

Abscess

localized acute inflammation with liquifactive necrosis

Caseous necrosis

caused by tuberculosis with a marginal zone of aggregated macrophages and a central zone of necrosis containing amorphous debris derived from necrotic host cells and necrotic mycobacterial cells

Granulomas

nodular gross lesions

Granulomatous inflammation

dense infiltrates of macrophages

Fat necrosis

specifically affects adipose tissue and most commonly results from pancreatitis or trauma, resulting in the release of lipases that free up fatty acids and bind to calcium, causing saponification

Saponification

the formation of soaps

Inflammation

reaction of tissue to a pathogenic insult. Rubor, tumor, calor, dolor and functio laesa (loss of function). Three features: vasodilation, increased permeability and recruitment of inflammatory cells.

Acute inflammation

densely packed polymorphonuclear neutrophils (PMNs) with multilobed nuclei. Includes vasodilation (redness) and increased permeability (transudation of fluid causing edema). Activation of humoral mediators causes pain, exudation of plasma proteins and transmigration of neutrophils

Chronic inflammation

influx of numerous mononuclear leukocytes (lymphocytes, monocytes, macrophages and plasma cells) and increased extracellular matrix (collagen)

Degranulation

Immediate response of tissue cells to injury (think mast cells)

Granulation tissue

final stage of repair characterized by new capillaries in young fibrous tissue

Early events of injury

injury, then humoral (coagulation) and cellular (platelet, mast cell, neutrophil and endothelial) activation

Monocytes

enter sites of acute inflammation after early events and release factors similar to neutrophils before undergoing apoptosis, transforming into macrophages

Macrophages

phagocytic, secrete cytokines that attract lymphocytes

Growth/proliferation factors

mediate repair and are produced by lymphocytes, macrophages, fibroblasts and endothelial cells

Fibrosis

scarring, can occur if excess collagen remains at sites of repair

Thrombosis

involves activation of circulating platelets and coagulation factors. Occurs when endothelial function is altered, endothelial continuity is lost or blood flow is reduced.

Hemorrhagic diseases

caused by inadequate thrombosis

Ischemic disease

lack of O2 delivery, caused by thrombosis obstructing adequate flow.

Embolization

means carried in the bloodstream and causes thromboembolic disease (ex.: lower extremity deep vein thrombosis a.k.a. DVT)

Clotting

thrombosis in a test tube

Organization

potential outcome of a DVT, turning into solid tissue

Recanalization

possible outcome of a DVT, new blood channels are formed around it

Partial thromboplastin time

PTT, blood test that measures the time it takes for blood to clot

Autosomal dominant polycystic kidney disease (ADPKD)

example of genetic abnormal morphogenesis

Agenesis

complete absence of an organ or component of an organ

Aplasia

persistence of an undeveloped organ anlage (rudimentary mass) without the mature organ

Hypoplasia

reduced size caused by incomplete development

Atresia

incomplete formation of a lumen

Dysplasia (morphogenesis)

abnormal tissue differentiation during development

Ectopia

normally formed organ that is outside its normal anatomic location

Microcephaly

can be induced by maternal Zika virus infection

Teratogen

a factor that causes malformation of an embryo

D-dimers

degraded fibrin

Cystic fibrosis

most common lethal autosomal recessive disorder in caucasians. Results from defect in the cystic fibrosis transmembrane conductance regulator (CFTR) and causes chronic pulmonary disease, deficient exocrine pancreatic function and other complications of mucus in multiple organs

Hydropic degeneration

abnormal swelling from increased water within organelles caused by injury due to a toxin

Desmoplasia

refers to the growth of fibrous or connective tissue following an injury (can be a reaction against invasive cancer)