Histopathologic and Cytologic Techniques – Vocabulary (Key Concepts)

Vocabulary flashcards covering major pathology concepts from the notes.

Pathology

The study of disease — its causes, mechanisms, and effects, including cellular, tissue, and organ changes that produce signs and symptoms.

Etiology

Origin of a disease; the underlying causes and modifying factors (genetic or acquired).

Pathogenesis

The sequence of events and mechanisms by which a disease develops and progresses.

Signs

Objective evidence of disease that can be measured or observed by others (e.g., fever, rash).

Symptoms

Subjective evidence of disease reported by the patient (e.g., pain, fatigue).

General Pathology

Study of cellular and tissue alterations caused by pathologic stimuli across tissues.

Systemic Pathology

Examination of reactions and abnormalities in different specialized organs.

Clinical Pathology

Laboratory branch dealing with chemical and cellular analysis of blood and body fluids and identification of microbes and parasites.

Anatomic Pathology

Processing and examination of surgical specimens for physical appearance and microscopic structure; includes cytopathology, IHC, autopsy, and forensic pathology.

Molecular Pathology

Analysis of genes, proteins, and other molecules to diagnose disease and guide prevention and treatment.

Cellular Adaptation

reversible changes by which cells respond to stress to maintain homeostasis.

Retrogressive Changes

Developmental or degenerative changes describing underdevelopment or loss of tissue size.

Aplasia

Incomplete or defective development of a tissue/organ; may resemble fatty or fibrous tissue.

Agenesis

Complete non-appearance of an organ.

Hypoplasia

Failure of an organ to reach its adult size due to incomplete development.

Atresia

Failure of an organ to form an opening.

Atrophy

Acquired decrease in size of a tissue/organ; can be physiologic or pathologic.

Physiologic Atrophy

Normal atrophy due to aging or adaptive processes.

Pathologic Atrophy

Atrophy due to disease or abnormal conditions.

Hypertrophy

Increase in size of tissues/organs due to enlargement of individual cells; includes true, false, and compensatory types.

True Hypertrophy

Increase in cell size from workload or endocrine stimulation.

False Hypertrophy

Increase in tissue size due to edema and connective tissue proliferation rather than cell enlargement.

Compensatory Hypertrophy

Hypertrophy that occurs after removal or dysfunction of a paired organ, promoting growth of the remaining tissue.

Hyperplasia

Increase in tissue size due to a higher number of cells; can be physiologic or pathologic.

Physiologic Hyperplasia

Normal tissue growth in response to hormonal or compensatory signals.

Pathologic Hyperplasia

Hyperplasia due to disease or abnormal stimulation.

Metaplasia

Replacement of one differentiated cell type by another; an adaptive, often reversible change.”

Dysplasia

Disordered growth with variation in size, shape, and orientation of cells, often linked to chronic inflammation and irritation.

Anaplasia

Loss of differentiation with a shift toward primitive/embryonic cell features; a hallmark of malignancy.

Neoplasia

Uncontrolled, abnormal proliferation of cells forming a neoplasm.

Necrosis

Pathologic cell death due to severe injury, with membrane damage and enzymatic digestion of the cell.

Apoptosis

Programmed, controlled cell death; often physiologic or regulated in response to damage; typically without inflammation.

Coagulative Necrosis

Necrosis with firm, coagulated tissue; cells preserve outline but lack nuclei; “tombstone” appearance microscopically.

Liquefactive Necrosis

Rapid enzymatic digestion of cells leading to tissue destruction; common in infections.

Gangrenous Necrosis

Extensive necrosis due to ischemia, often with superimposed infection; can be wet or dry.

Caseous Necrosis

Cheese-like, friable tissue typical of tuberculosis.

Fat Necrosis

Destruction of adipose tissue due to lipase; fat saponification with calcium deposition.

Fibrinoid Necrosis

Immunologically mediated necrosis with antigen-antibody complexes and fibrin in vessel walls.

Inflammation

Protective response to infection or injury bringing leukocytes and proteins to the site to remove microbes and dead tissue; with cardinal signs.

Cardinal Signs of Inflammation

Calor (heat), Rubor (redness), Tumor (swelling), Dolor (pain), Functio Laesa (loss of function).

Acute Inflammation

Rapid onset with neutrophil-predominant infiltrate; usually self-limited.

Chronic Inflammation

Long-standing inflammation with monocytes/macrophages and lymphocytes; can be progressive.

Exudates

Protein-rich fluid or cells that escape into tissue due to increased vascular permeability; includes serous, fibrinous, hemorrhagic, purulent, and catarrhal variants.

Granulomatous Inflammation

Chronic inflammation characterized by activated macrophages forming granulomas to contain difficult-to-eradicate agents.

Tissue Repair

restoration of tissue architecture and function after injury via regeneration and/or scar formation.

Regeneration

Proliferation of residual/uninjured cells to restore tissue; depends on growth factors and intact extracellular matrix.

Scar Formation

Deposition of connective tissue when regeneration is insufficient; fibrosis increases.

Fibrosis

Extensive deposition of collagen due to chronic inflammation, contributing to scar tissue.

Healing by First Intention

Repair of minimal tissue disruption; regeneration predominates; small scar; wound edges closed by sutures.

Healing by Second Intention

Repair of extensive tissue loss; regeneration plus scar formation; more inflammation and larger scar.

Factors Influencing Tissue Repair

Infection, nutrition, glucocorticoids, mechanical factors, perfusion, foreign bodies, injury location, and aberrations of cell growth.

Growth Factors

Proteins that stimulate survival and proliferation of specific cells; promote cell cycle progression and inhibit apoptosis.

Epidermal Growth Factor (EGF)

Growth factor that stimulates keratinocyte and fibroblast proliferation and wound healing.

Transforming Growth Factor-α (TGF-α)

Growth factor that promotes proliferation of hepatocytes and other epithelial cells.

Hepatocyte Growth Factor (HGF)

Growth factor that promotes proliferation and motility of epithelial cells; also called scatter factor.

Vascular Endothelial Growth Factor (VEGF)

Growth factor that stimulates endothelial cell proliferation and angiogenesis; increases vascular permeability.

Platelet-Derived Growth Factor (PDGF)

Growth factor with chemotactic/mitogenic effects on fibroblasts and endothelial cells; promotes ECM synthesis and angiogenesis.

Fibroblast Growth Factors (FGFs)

Family of growth factors promoting fibroblast and endothelial cell proliferation and angiogenesis.

Transforming Growth Factor-β (TGF-β)

Growth factor that modulates ECM production and inflammation; often anti-inflammatory.

Keratinocyte Growth Factor (KGF/FGF-7)

Growth factor that stimulates keratinocyte migration, proliferation, and differentiation.

Cell Cycle Phases

G0: quiescent; G1: pre-synthetic; S: DNA synthesis; G2: pre-mitotic; M: mitotic; with interphase between cycles.

Extracellular Matrix (ECM)

Complex network of proteins surrounding cells; provides support, binds water/minerals, and stores growth factors.

ECM Components

Collagen and elastin; proteoglycans and hyaluronan; adhesive glycoproteins.

Role of ECM in Repair

Mechanical support, regulation of cell proliferation, scaffold for renewal, and microenvironment formation.

Labile Tissues

Tissues with continuous turnover that regenerate readily (e.g., bone marrow, skin, mucosa).

Stable Tissues

Inert cells with low baseline activity but capable of proliferation after injury (e.g., liver, kidney).

Permanent Tissues

Terminally differentiated cells that do not proliferate (e.g., neurons, cardiac muscle).

Stem Cells

Cells with the capacity for self-renewal and differentiation into specialized cells.

Self-renewal

Ability of stem cells to divide and produce more stem cells.

Asymmetric Replication

Division yielding one identical daughter cell and one progenitor cell, enabling maintenance and differentiation.

Embryonic Stem Cells

Pluripotent stem cells from early embryos; can give rise to all cell types.

Adult Stem Cells

Stem cells found in tissues with limited self-renewal and lineage potential restricted to the tissue.