Introduction to Pathology and Cell Injury

Flashcards covering the history of pathology, cell theory, mechanisms of cell injury, diseases of protein misfolding, cellular adaptations, and postmortem changes.

Edwin Smith Papyrus

The eldest known paper describing pathological changes, dating back to the $17^{th}$ century BC.

Hippocrates

An ancient figure who applied the Humoral Theory to explain the origins of diseases.

Rudolf Virchow

Known as the Father of Modern Pathology; he used the microscope in tissue analysis and proposed the third tenet of Cell Theory.

James Baccus (1994)

Developer of Whole Slide Imaging (WSI) technology, contributing to the field of Digital Pathology.

Pathology

The study ($logos$) of disease ($pathos$, suffering), involving the investigation of causes and associated changes in cells, tissues, and organs.

Etiology

The origin of a disease, including its underlying causes and modifying factors.

Pathogenesis

The steps in the development of a disease, describing how etiologic factors trigger cellular and molecular changes leading to functional and structural abnormalities.

Zacharias Janssen

Inventor of the first compound microscope in 1590.

Robert Hooke

Used a light microscope in 1665 to look at plant tissue (cork) and coined the term cell.

Anton van Leeuwenhoek

The first to see living organisms under a microscope in 1673, which he termed animalcules.

Matthias Schleiden and Theodore Schwann

Proposed the first two tenets of Cell Theory: that all living plants (Schleiden, 1838) and animals (Schwann, 1839) are made of cells.

Homeostasis

A steady state in which the intracellular milieu is kept within a fairly narrow range of physiologic parameters.

Hypoxia

A lack of $O_2$ availability in tissues.

Hypoxemia

A relative deficiency of $O_2$ in the blood, specifically an arterial PO_2 < 80\,mmHg.

Dysoxia

A lack of $O_2$ utilization by tissues.

Ischemia

Diminished blood flow to a tissue, which compromises the delivery of substrates for glycolysis and is a common cause of acute cell injury.

Ischemia-Reperfusion Injury

Paradoxical cell death caused by restoring blood flow to ischemic but viable tissues, primarily due to dysfunctional ion transport and membrane damage.

Mercuric Chloride Poisoning

A direct mechanism of toxic injury where mercury binds to sulfhydryl groups of cell membrane proteins, inhibiting ATP-dependent transport.

Cytochrome P-450

Enzymes in the smooth ER of the liver that convert non-intrinsically active chemicals into reactive toxic metabolites (indirect mechanism).

Free Radicals

Extremely unstable chemical species with a single unpaired electron in an outer orbital that attack nucleic acids, proteins, and lipids.

Cystic Fibrosis

A disease where misfolding of the CFTR protein leads to defects in $Cl^-$ transport.

Tay-Sachs Disease

A condition where a lack of the lysosomal enzyme Hexosaminidase B subunit leads to the storage of GM2 gangliosides in neurons.

Creutzfeld-Jacob Disease

A disease characterized by the abnormal folding of Prions (PrP), causing neuronal cell death.

Anthracosis

The blackening of draining lymph nodes and pulmonary parenchyma due to the accumulation of inhaled carbon (coal dust).

Lipofuscin

An insoluble brownish-yellow granular intercellular material known as the wear-and-tear pigment; a marker of past free radical injury.

Hemosiderin

A hemoglobin-derived golden yellow to brown granular pigment representing large aggregates of ferritin micelles, occurring during iron excess.

Atrophy

A decrease in the number and size of cells.

Hypertrophy

An increase in the size of cells.

Hyperplasia

An increase in the number of cells.

Metaplasia

The reversible transformation of one mature cell type into another (epithelial or mesenchymal) due to external stimuli.

Dysplasia

Abnormal, disordered cellular development occurring in epithelial cells due to the alteration of genetic material.

Situs Inversus

A rare genetic condition in which the organs in the chest and abdomen are reversed.

Liquefaction Necrosis

A type of necrosis where dead cells liquefy due to the action of specific cellular enzymes.

Caseous Necrosis

A form of coagulation necrosis resulting in dense, yellowish, cheesy matter.

Algor mortis

The first demonstrable secondary change of somatic death, characterized by the cooling of the body.

Rigor mortis

The rigidity or stiffening of the muscles following somatic death.

Livor mortis

The purplish discoloration or lividity of the skin after death.

Calor, Rubor, and Tumor

Cardinal signs of inflammation referring to heat, redness (both caused by vasodilation), and swelling (caused by increased vascular permeability).

Dolor and Functio laesa

Cardinal signs of inflammation referring to pain (stimulation of nociceptors) and loss of function.

Neutrophils

The major cell type involved in the immediate onset of acute inflammation.