General Pathology for Animal Health

Comprehensive vocabulary flashcards covering general pathology concepts, cell death, inflammation, repair, hemodynamic disorders, cellular adaptations, and neoplasia based on animal health lecture notes.

Pathology

The study of disease (from Greek pathos = suffering or disease and logos = study), dealing with structural and functional changes in cells, tissues, and organs that underlie disease.

General Pathology

The branch of pathology concerned with the basic reactions of cells and tissues to injurious stimuli.

Systemic Pathology (Special Pathology)

The application of basic pathologic reactions to specific body systems or individual diseases.

Aetiology

The cause of a disease process, categorized into intrinsic (genetic/predisposing) and extrinsic (acquired/environmental) factors.

Pathogenesis

The progressive sequence of events in the response of cells and tissues to a causal agent, from initial stimulus to the ultimate development and conclusion of the disease.

Lesion

Any macroscopic or microscopic structural alteration occurring in a tissue as a result of injury.

Pathognomonic Lesion

A specific alteration that points without doubt to the cause of a particular disease, such as button-shaped ulcers of the large intestine in swine fever.

Clinical Pathology

The branch of pathology involving laboratory examination of blood, urine, faeces, exudates, skin scrapings, and biopsy specimens to aid in diagnosis.

Diagnosis

The art or act of recognizing and identifying a disease state through its clinical signs, symptoms, and laboratory findings.

Prognosis

A forecast about the probable course, duration, and chances of recovery from a disease.

Invalidism

A disease termination outcome where tissue injury is not fatal but cannot be fully repaired, resulting in prolonged ill health.

Necropsy

The postmortem examination of an animal or bird to establish the cause of death.

Autopsy

The postmortem examination of a human body to determine the cause of death.

Biopsy

The examination of tissue removed from a living animal to determine the cause or nature of disease.

Syndrome

A group of symptoms and signs occurring together that characterize a specific disease or abnormality.

Idiosyncrasy

An unusual, unpredictable individual reaction to a substance or drug that may cause severe manifestations of toxicity or death.

Hypoxia

A deficiency of oxygen supply to tissues that impairs aerobic oxidative respiration.

Ischaemia

A local deficiency of blood supply caused by obstructed arterial inflow or hindered venous outflow, depleting tissues of oxygen and metabolic substrates faster than hypoxia alone.

Necrosis

The localized death of cells or tissues within a living organism, resulting from enzymatic degradation and protein denaturation of irreversibly injured cells.

Autolysis

Enzymatic self-digestion of dead cells driven by hydrolytic enzymes derived from their own lysosomes.

Heterolysis

Enzymatic digestion of dead or damaged cells by hydrolytic enzymes derived from the lysosomes of infiltrating leukocytes.

Coagulative Necrosis

A form of necrosis where denaturation of structural and enzymatic proteins predominates, preserving cellular outlines and basic tissue architecture for days.

Liquefactive Necrosis

A form of necrosis characterized by powerful enzymatic digestion that transforms dead tissue into a soft, liquid mass, with total loss of cellular and architectural detail.

Caseous Necrosis

A distinctive form of necrosis seen typically in tuberculosis and caseous lymphadenitis, where dead tissue converts into a soft, friable, cheesy, and granular amorphous mass.

Fat Saponification

The process occurring in fat necrosis where pancreatic lipases hydrolyze triglycerides into fatty acids that combine with calcium, forming grossly visible chalky white deposits.

Apoptosis

A pathway of coordinated, internally programmed cell death designed to eliminate unwanted or damaged cells through gene-regulated mechanisms without inducing inflammation.

Gangrene

The invasion and putrefaction of necrotic tissue by saprophytic bacteria.

Dry Gangrene

A form of gangrene usually occurring in cool extremities with minimal moisture, where coagulative necrosis predominates and the dead tissue becomes dehydrated, shrivelled, and mummified.

Moist Gangrene

A form of gangrene occurring in warm, internal organs with abundant moisture, characterized by rapid bacterial growth, liquefactive putrefaction, gas accumulation, and lack of a sharp demarcation line.

Pseudomelanosis

A postmortem or gangrenous black discoloration of tissue produced when hydrogen sulphide from bacterial decomposition combines with iron from haemoglobin to form black iron sulphide.

Inflammation

The vascular and cellular reaction of living tissues to injury, leading to the accumulation of fluid and leukocytes in extravascular tissue to neutralize harmful agents and promote repair.

Cardinal Signs of Inflammation

The five principal local manifestations of acute inflammation: redness (rubor), swelling (tumor), heat (calor), pain (dolor), and loss of function (functio laesa).

Polymorphonuclear Leukocyte (Neutrophil)

A granulocyte with a multi-lobed nucleus that represents the first line of cellular defence in acute inflammation, arriving first at the site of injury.

Exudate

An inflammatory extravascular fluid with a high protein content (greater than $4\%$), high specific gravity ($1.020$ or higher), and abundant leukocytes and cellular debris.

Transudate

A non-inflammatory extravascular fluid with low protein content (less than $3\%$), low specific gravity ($1.012$ or lower), and few or no cells, produced by altered hydrostatic or osmotic pressures.

Catarrhal (Mucous) Inflammation

A mild form of inflammation restricted to mucous membranes and glandular ducts, characterized by an exudate rich in clear mucin and water.

Serous Inflammation

An acute inflammatory pattern marked by the outpouring of a thin, watery, protein-poor fluid derived from blood serum or mesothelial secretions, commonly presenting as blisters.

Fibrinous Inflammation

Inflammation resulting from severe vascular permeability that allows fibrinogen to escape into tissues and form a prominent fibrin network on surfaces or within organs.

Suppuration

The formation of pus, which requires necrosis of tissue, accumulation of abundant neutrophils, and enzymatic digestion of dead tissue by proteolytic enzymes.

Pus

An alkaline, creamy inflammatory exudate consisting of dead and dying neutrophils, liquefied necrotic parenchymal cells, and tissue fluid.

Cellulitis (Phlegmon)

A diffusely spreading, uncircumscribed suppurative inflammation of connective tissue, typically caused by streptococci and marked by red, raised borders.

Abscess

A localized, circumscribed collection of pus contained within a cavity formed by tissue destruction.

Pyogenic Membrane

The limiting inflammatory zone forming the inner wall of an abscess that continually sheds necrotic material and leukocytes into the purulent cavity.

Sinus

A blind-ending inflammatory tract running from a deep suppurative focus to an epithelial surface to discharge pus.

Fistula

An abnormal, communicating tract connecting two epithelial surfaces (such as skin and a mucous membrane) that discharges purulent exudate.

Furuncle (Boil)

A focal, painful suppurative inflammation of the skin involving a hair follicle or sebaceous gland, caused by Staphylococcus aureus.

Pustule

A small, circumscribed epidermal cavity or elevation filled with pus.

Haemorrhagic Inflammation

A severe form of inflammation characterized by massive vascular damage and an exudate dominated by extravasated erythrocytes.

Chronic Inflammation

Inflammation of prolonged duration (weeks to years) in which active inflammation, tissue destruction, and repair with mononuclear cell infiltration and fibrosis proceed simultaneously.

Granulation Tissue

Vascularized, immature connective tissue containing proliferating fibroblasts, new capillaries (angiogenesis), and loose extracellular matrix that fills tissue gaps during healing.

Healing by First Intention (Primary Union)

The healing of a clean, uninfected, closely approximated surgical wound with minimal tissue loss, where epithelial regeneration predominates over fibrosis.

Healing by Second Intention (Secondary Union)

The repair process in wounds with extensive tissue loss, ulceration, or infection, requiring extensive granulation tissue deposition and wound contraction to close the defect.

Wound Contraction

The inward pull of the edges of a large wound occurring during secondary healing, mediated by myofibroblasts and reducing wound size by up to $90\%$ to $95\%$.

Hyperaemia

An active vascular process resulting in an increased volume of arterial blood flow within an organ or tissue due to arteriolar dilation.

Congestion (Passive Hyperaemia)

A passive hemodynamic condition characterized by an abnormal accumulation of venous blood in an organ or tissue due to impaired venous outflow.

Cyanosis

A bluish-red discoloration of tissues and mucous membranes caused by high concentrations of deoxygenated haemoglobin in the venous blood.

Haemorrhage by Rhexis

Bleeding resulting from a visible mechanical break, laceration, or complete rupture in the continuity of a blood vessel wall.

Haemorrhage by Diapedesis

The passage of red blood cells through an apparently intact, hyperpermeable vascular wall via microscopic intercellular gaps.

Petechiae

Minute, pinpoint-sized, punctate haemorrhages into skin, mucous membranes, or serosal surfaces measuring $1-2\,\text{mm}$ in diameter.

Purpura

Haemorrhages intermediate in size between petechiae and ecchymoses, measuring approximately $3-5\,\text{mm}$ in diameter.

Ecchymoses

Large, blotchy extravasations of blood into tissues measuring approximately $1-2\,\text{cm}$ in diameter.

Haematoma

A localized, three-dimensional accumulation of clotted or extravasated blood enclosed entirely within an organ, tissue, or space.

Epistaxis

Haemorrhage originating from the nasal cavity (bleeding from the nose).

Haemoptysis

The coughing up or spitting of blood derived from the lungs or bronchial tree in sputum.

Haematemesis

The vomiting of blood derived from the stomach or upper digestive tract.

Melena

The passage of black, tarry, altered blood in the faeces resulting from bleeding in the upper gastrointestinal tract.

Thrombosis

The pathological formation of an organized, adherent clotted mass of platelets, fibrin, and blood cells within the cardiovascular system during life.

Embolus

A detached, circulating intravascular mass (solid, liquid, or gaseous) carried by the bloodstream from its site of origin to a distant site, where it may obstruct flow.

Oedema

An excessive accumulation of fluid in the interstitial tissue spaces or body cavities.

Anasarca

Severe, generalized, massive subcutaneous oedema accompanied by diffuse swelling of body tissues.

Infarct

A discrete area of ischaemic necrosis in a tissue or organ caused by occlusion of its arterial blood supply or occasionally its venous drainage.

Shock

A life-threatening systemic hemodynamic collapse characterized by widespread tissue hypoperfusion, cellular hypoxia, and metabolic insufficiency.

Hypovolaemic Shock

Shock resulting from a critical reduction in circulating blood or plasma volume due to massive haemorrhage, dehydration, burns, or severe fluid loss.

Cardiogenic Shock

Shock resulting from intrinsic myocardial pump failure, as seen in extensive myocardial infarction, tamponade, or major outflow obstruction.

Aplasia

The complete failure of an organ or tissue to develop during embryonic or foetal development.

Hypoplasia

The incomplete development or underdevelopment of an organ or tissue, resulting in a reduced number of cells and failure to achieve normal adult size.

Atrophy

A reduction in the size of cells due to loss of cell substance, resulting in a decrease in the volume and mass of a previously fully developed organ or tissue.

Hypertrophy

An increase in the size of individual cells leading to enlargement of an organ, caused by enhanced synthesis of structural proteins and organelles without cell division.

Hyperplasia

An increase in the number of parenchymal cells within an organ or tissue resulting from accelerated mitotic division.

Metaplasia

A reversible phenotypic change in which one fully differentiated adult cell type is replaced by another adult cell type better able to endure local environmental stress.

Dysplasia

Disorderly, non-neoplastic proliferation characterized by cellular pleomorphism, hyperchromatic enlarged nuclei, and disrupted tissue architectural orientation.

Carcinoma in Situ

A preinvasive malignant epithelial alteration where marked dysplastic changes involve the full thickness of the epithelium without breach of the basement membrane.

Neoplasm

An abnormal mass of new tissue that proliferates autonomously without physiologic control, serves no useful function, and exhibits uncoordinated growth.

Benign Neoplasm

A non-invasive, localized tumor that grows slowly, develops a fibrous capsule, does not metastasize, and does not cause death unless mechanically obstructing vital structures.

Malignant Neoplasm (Cancer)

A locally invasive and destructive tumour capable of rapid growth, metastasis to distant anatomical sites, and causing death of the host.

Anaplasia

The lack of structural and functional differentiation of cells, characterized by pleomorphism, nuclear hyperchromatism, and primitive morphology; a hallmark of malignancy.

Metastasis

The dissemination and secondary growth of malignant tumor cells in tissues that are discontinuous from the primary neoplasm, transmitted via vascular or lymphatic channels or surface seeding.

Carcinoma

A malignant neoplasm derived from epithelial cells of ectodermal, mesodermal, or endodermal origin, which predominantly metastasizes via lymphatic pathways.

Sarcoma

A malignant neoplasm derived from mesenchymal or connective tissues (such as bone, cartilage, muscle, or fibrous tissue), which commonly disseminates via haematogenous routes.

Papilloma

A benign epithelial neoplasm forming macroscopic or microscopic finger-like or warty projections on an epithelial surface.

Adenoma

A benign epithelial neoplasm derived from glandular tissue or forming glandular structures.

Leiomyoma

A benign neoplasm arising from smooth muscle cells.

Rhabdomyosarcoma

A malignant neoplasm arising from striated (skeletal) muscle cells.