Review Notes in Histopathologic and Cytologic Techniques

Comprehensive vocabulary flashcards covering histotechniques, general pathology, inflammation, cellular adaptations, somatic death, and fixative chemistry from Hero's Part 1 WINNER Notes.

Histology

The microscopic study of the tissues of the body.

Epithelial Tissue

Lining, covering, and glandular tissue of the body derived from the ectoderm, mesoderm, and endoderm that functions in protection, absorption, and secretion.

Connective Tissue

Tissue derived from embryonic mesoderm (mesenchyme) that underlies or supports the other three basic tissues structurally and functionally, acts as an exchange medium, and stores fat.

Muscular Tissue

Tissue of mesodermal origin composed of contractile cells responsible for movement.

Nervous Tissue

Tissue originating from the ectoderm that receives, transmits, and integrates information to control body activities, with irritability and conductivity as its primary functions.

Pseudostratified Epithelium

A special type of simple epithelium consisting of a single layer of cells where some are tall and reach the free surface while others do not, giving a false appearance of multiple layers.

Transitional Epithelium (Urothelium)

A specialized stratified epithelium capable of considerable stretching, found lining the urinary bladder, ureter, and urethra.

Endocrine Glands

Ductless glands whose secretory products diffuse directly into the blood vessels that weave through them (e.g., pituitary, thyroid, adrenal, and pancreas).

Exocrine Glands

Glands that retain their ducts and empty secretions directly to the epithelial surface (e.g., sweat, sebaceous, salivary glands, and pancreas).

Holocrine Secretion

A mode of exocrine secretion that involves the shedding and destruction of entire cells, which become part of the secretory product.

Merocrine Secretion

A mode of exocrine secretion that involves the release of secretory products across the cell membrane by exocytosis without loss of cell substance.

Apocrine Secretion

A mode of exocrine secretion that involves the release of secretory products within pinched-off fragments of the gland cells.

Fibroblasts

The most common cells found in connective tissue, responsible for tissue repair and wound healing.

Areolar Tissue

The most widely distributed loose connective tissue proper that functions as a universal 'glue' to pack and hold internal organs in their proper positions.

Hyaline Cartilage

The most common supporting cartilage tissue, found in the nasal septum, larynx, tracheal rings, ribs, and developing skeleton.

Fibrocartilage

Supporting connective tissue found in intervertebral discs, joint capsules, ligaments, and tendons.

Elastic Cartilage

Flexible cartilage found in the external ear, external auditory canal, epiglottis, and walls of the Eustachian tubes.

Skeletal Muscle

Voluntary muscle tissue attached to the skeleton, characterized by long, cylindrical, multinucleated cells with striations.

Cardiac Muscle

Involuntary muscle tissue of the heart consisting of short, uninucleated, striated, and branching cells connected by intercalated discs.

Smooth Muscle

Involuntary, non-striated visceral muscle tissue composed of uninucleated, spindle-shaped cells located in hollow organs such as the gastrointestinal tract, ureter, urinary bladder, and uterus.

Pathology

The study of suffering (Greek pathos = suffering; logos = study), dealing with structural, biochemical, and functional changes in cells, tissues, and organs.

Rudolf Ludwig Carl Virchow

The historical figure recognized as the Father of Modern Pathology.

Etiology

The origin or causative agent of a disease.

Pathogenesis

The sequence of events that follow the exposure of cells or tissues to an injurious agent.

Morphologic Changes

Structural alterations in cells or tissues that are characteristic of a disease or diagnostic of an etiologic process.

Signs

Objective evidence of disease determined by physical observations or measurable parameters (e.g., fever, rashes, high blood pressure, and abnormal lab results).

Symptoms

Subjective evidence of disease experienced and reported directly by the patient (e.g., headache, pain, fatigue, and chest pain).

Rubor

Redness; the first cardinal sign of inflammation caused by arteriolar and capillary dilatation with an increased rate of blood flow toward the site of injury.

Tumor (Inflammatory Sign)

Swelling; cardinal sign of inflammation due to increased capillary permeability that allows the extravasation of blood fluid associated with increased hydrostatic pressure.

Calor

Heat; cardinal sign of inflammation caused by the transfer of internal heat to the site or surface of injury.

Dolor

Pain; cardinal sign of inflammation caused by pressure upon sensory nerves exerted by exudates or swelling.

Functio Laesa

Loss of function; the last cardinal sign of inflammation resulting from pain interference with nerve supply and destruction of functioning tissue units.

Acute Inflammation

Inflammation of sudden onset persisting for days (usually $< 7\,\text{days}$) in which neutrophils represent the predominant cell type.

Chronic Inflammation

Inflammation involving the persistence of an injurious agent for weeks or years, characterized by proliferation and mononuclear cells (plasma cells, lymphocytes, macrophages).

Catarrhal Inflammation

Inflammation characterized by the hypersecretion of mucosa accompanied by degenerative changes in the epithelium, such as in the common cold.

Aplasia

Incomplete or defective development of a tissue or organ.

Agenesia

Complete non-appearance of an organ.

Atresia

Failure of an organ or hollow structure to form an opening.

Atrophy

Acquired decrease in size of a previously normally developed or mature tissue or organ.

Hypoplasia

Failure of an organ to reach or achieve its full mature or adult size due to incomplete development.

Hypertrophy

An increase in the size of tissues or organs caused by an increase in the size of individual cells.

Hyperplasia

An increase in the size of an organ or tissue caused by an increase in the total number of cells.

Dysplasia

A regressive alteration in adult cells manifested by variation in size, shape, and orientation, typically associated with chronic inflammation and protracted irritation.

Anaplasia

Marked regressive change in adult cells toward more primitive or embryonic cell types, used as a key criterion for malignancy.

Metaplasia

A reversible change involving the transformation of one adult cell type into another adult cell type.

Neoplasia

A pathologic overgrowth of tissue characterized by continuous, autonomous, and uncontrolled abnormal proliferation of cells.

Parenchyma (Tumor)

The active proliferating cellular elements of a tumor.

Stroma (Tumor)

The supporting connective tissue framework of a tumor, encompassing its lymphatic and vascular channels.

Carcinoma

A malignant tumor arising from epithelial tissue origin.

Sarcoma

A malignant tumor arising from connective tissue origin.

Medullary Tumors

Neoplasms containing more parenchymal cells than connective tissue, characterized as soft and highly malignant.

Scirrhous Tumors

Neoplasms containing more connective tissue stroma than cells, characterized histologically as stony, hard, and showing cells trapped in fibrous tissue.

Broder's Grade I

A histologic tumor grade defined by $75\text{--}100\%$ differentiated cells and $0\text{--}25\%$ undifferentiated cells.

Broder's Grade IV

A histologic tumor grade defined by $0\text{--}25\%$ differentiated cells and $75\text{--}100\%$ undifferentiated cells.

Impairments (WHO)

Any loss or abnormality of psychological, physiological, or anatomical structure or function.

Disabilities (WHO)

Any restriction or lack of ability to perform an activity in the manner or within the range considered normal for a human being.

Handicap (WHO)

A disadvantage for a given individual resulting from an impairment or disability that limits or prevents the fulfillment of a normal role.

Apoptosis

Programmed, often physiologic cell death utilized to eliminate unwanted cells, morphologically characterized by nuclear condensation.

Necrobiosis

Physiologic death of cells occurring throughout the normal life cycle.

Necrosis

Pathologic death of cells or tissues within a living organism resulting from irreversible injury.

Pyknosis

A nuclear hallmark of necrosis characterized by a reduction in nuclear size and condensation of chromatin.

Karyorrhexis

A nuclear hallmark of necrosis characterized by segmentation and fragmentation of the nucleus.

Karyolysis

A nuclear hallmark of necrosis characterized by dissolution and fading of the nucleus.

Coagulative Necrosis

The most common form of necrosis, characterized by tombstone formation and preservation of basic tissue outline, usually caused by cut-off arterial blood supply.

Liquefactive Necrosis

Necrosis marked by rapid total enzymatic dissolution of tissue into pus, commonly seen in bacterial infections and hypoxic death of central nervous system brain tissue.

Caseous Necrosis

A distinct form of necrosis with a soft, friable, cheese-like gross appearance, characteristically associated with tuberculosis.

Algor Mortis

The first demonstrable secondary change of somatic death, characterized by cooling of the body at a rate of approximately $7^\circ\text{E}$ per hour.

Rigor Mortis

Muscular rigidity and stiffening appearing $6\text{ to }12\,\text{hours}$ after death and persisting for $3\text{ to }4\,\text{days}$, initiating in the head and neck before progressing downward.

Livor Mortis

Purplish post-mortem discoloration of dependent parts of the body caused by vascular stasis and settling of blood, which temporarily clears under localized pressure.

Putrefaction

The post-mortem decomposition of tissue characterized by the release of foul-smelling gases caused by multiplying saprophytic bacteria.

Autolysis

Self-digestion and breakdown of cells caused by their own intracellular catalytic enzymes.

Biopsy

The surgical removal of a tissue sample from a living organism for microscopic examination to establish a medical diagnosis.

Fine Needle Aspiration (FNA)

The simplest and least invasive biopsy technique, utilizing a fine needle ($22\,\text{g}$, $10\,\text{cc}$) to aspirate cells from a suspicious mass.

Punch Biopsy

The primary technique for obtaining diagnostic full-thickness skin specimens using a circular blade rotated through the skin to obtain a $3\text{ to }4\,\text{mm}$ cylindrical tissue core.

Frozen Section

A rapid microtomy technique in which fresh unfixed tissue is quick-frozen at $-20^\circ\text{C}$ and cut to provide an intra-operative diagnosis within approximately $15\,\text{minutes}$.

Cryostat

An insulated refrigerated chamber housing a rotary microtome operated at an optimum working temperature of $-18\text{ to }-20^\circ\text{C}$ for frozen section preparation.

Fixation

The first and most critical foundation step in routine tissue processing, which arrests cellular activity and stabilizes structural proteins to preserve tissue integrity.

10% Neutral Buffered Formalin (NBF)

The best general-purpose tissue immersion fixative, formulated with phosphate salts at pH $7.0$, prepared by diluting stock formaldehyde ($37\text{--}40\%$) tenfold ($1:10$).

Additive Fixation

A mechanism of fixation wherein the chemical constituents of the fixative become chemically bound and incorporated directly into the tissue components (e.g., formaldehyde, osmium tetroxide, mercuric chloride).

Non-Additive Fixation

A mechanism of fixation in which the fixing agent alters tissue hydration or composition without becoming chemically bound inside the tissue (e.g., alcohol fixatives).

Cross-Linking Fixatives

Fixatives such as aldehydes that act by forming covalent chemical cross-links between tissue proteins, anchoring them to the cytoskeleton.

Precipitating (Denaturing) Fixatives

Fixatives such as alcohols and acetone that reduce protein solubility and disrupt tertiary hydrophobic interactions, precipitating cellular proteins.

Paraformaldehyde

A white macroscopic crystalline polymer precipitate formed in concentrated formaldehyde during prolonged cold storage, removable by filtration or addition of $10\%$ methanol.

Acid Formaldehyde Hematin

A dark brown to black amorphous microcrystalline pigment formed when unbuffered, acidic formalin reacts with blood hemoglobin.

Dezenkerization

The procedure of removing black mercurial chloride deposits from tissue sections by immersion in alcoholic iodine followed by sodium thiosulfate.

Lead Citrate

A heavy metal stain recognized as the best and most widely used contrast stain for electron microscopy (EM) to demonstrate all cellular structures.