Fundamentals of Pathology: Growth Adaptations, Injury, and Inflammation

Vocabulary-style flashcards based on the introductory chapters of Dr. Husain Sattar's Fundamentals of Pathology, focusing on cell growth, death, injury, and initial inflammation concepts.

Hypertrophy

An increase in the size of cells, involving gene activation, protein synthesis, and production of organelles, resulting in an increase in organ size.

Hyperplasia

An increase in the number of cells from stem cells, which generally occurs together with hypertrophy to increase organ size.

Metaplasia

A change in stress on an organ that leads to a change in cell type, common in surface epithelium to better handle new stress; it occurs via reprogramming of stem cells.

Barrett esophagus

A classic example of metaplasia where the normal nonkeratinizing squamous epithelium of the esophagus changes to nonciliated, mucin-producing columnar cells due to acid reflux.

Keratomalacia

Metaplasia of the thin squamous lining of the conjunctiva into stratified keratinizing squamous epithelium due to Vitamin A deficiency.

Myositis ossificans

A form of mesenchymal metaplasia in which connective tissue within muscle changes to bone during healing after trauma.

Dysplasia

Disordered cellular growth, most often referring to the proliferation of precancerous cells; it is reversible in theory if the inciting stress is removed.

Aplasia

The failure of cell production during embryogenesis, such as unilateral renal agenesis.

Hypoplasia

A decrease in cell production during embryogenesis, resulting in a relatively small organ, such as a streak ovary in Turner syndrome.

Hypoxia

Low oxygen delivery to tissue which impairs oxidative phosphorylation and results in decreased ATP production, leading to cellular injury.

Ischemia

Decreased blood flow through an organ, which can arise from decreased arterial perfusion, decreased venous drainage, or shock.

Hypoxemia

A low partial pressure of oxygen in the blood, defined as $PaO_2 < 60\,mmHg$ and $SaO_2 < 90\%$, arising from causes like high altitude or hypoventilation.

Methemoglobinemia

A condition where iron in heme is oxidized to $Fe^{3+}$, which cannot bind oxygen; it is characterized by cyanosis and chocolate-colored blood.

Pyknosis

The morphologic stage of cell death involving nuclear condensation.

Karyorrhexis

The morphologic stage of cell death involving nuclear fragmentation.

Karyolysis

The morphologic stage of cell death involving nuclear dissolution.

Coagulative necrosis

Necrotic tissue that remains firm; cell shape and organ structure are preserved by coagulation of proteins, but the nucleus disappears. Characteristic of ischemic infarction (except in the brain).

Liquefactive necrosis

Necrotic tissue that becomes liquefied due to enzymatic lysis of cells and protein; characteristic of brain infarction, abscesses, and pancreatitis.

Caseous necrosis

Soft and friable necrotic tissue with a "cottage cheese-like" appearance; a combination of coagulative and liquefactive necrosis characteristic of granulomatous inflammation.

Saponification

A process in fat necrosis where fatty acids released by trauma or lipase join with calcium, resulting in a chalky-white appearance.

Dystrophic calcification

Calcium deposition on dead or necrotic tissues in the setting of normal serum calcium and phosphate levels.

Metastatic calcification

Calcium deposition in normal tissues due to high serum calcium or phosphate levels.

Apoptosis

Energy (ATP)-dependent, genetically programmed cell death involving single cells or small groups characterized by cell shrinkage and eosinophilic cytoplasm.

Caspases

Mediators of apoptosis that activate proteases to break down the cytoskeleton and endonucleases to break down DNA.

Free radicals

Chemical species with an unpaired electron in their outer orbit that cause cellular injury via peroxidation of lipids and oxidation of DNA and proteins.

Amyloid

A misfolded protein that deposits in the extracellular space, damaging tissues; it shares a $\beta$-pleated sheet configuration and apple-green birefringence under polarized light.

Familial Mediterranean fever (FMF)

An autosomal recessive dysfunction of neutrophils presenting with fever and acute serosal inflammation; high levels of SAA during attacks deposit as AA amyloid.

PAMPs

Pathogen-associated molecular patterns shared by microbes that activate Toll-like receptors (TLRs) on cells of the innate immune system.

Chemotaxis

The process by which leukocytes move toward chemical attractants such as bacterial products, $IL-8$, $C5a$, and $LTB_4$.

Anaphylatoxins

Complement fragments $C3a$ and $C5a$ which trigger mast cell degranulation, resulting in histamine-mediated vasodilation and increased vascular permeability.