DHY 207 Basic Pathology

DHY 207

Basic Pathology

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Concepts of the Pathologic Process

  • Pathology- study of disease or abnormal conditions resulting from disease, trauma, defects, genetic abnormalities, etc.
  • Etiology- Cause, can be single entity or event or multiple causes
  • Susceptibility- Conditions within or around the organism or host do not inhibit the action of pathogenic agents but instead leave the host more likely to be affected
  • Resistance- Natural ability of an organism to remain unaffected by pathogenic or toxic agents
  • Pathogenesis- How the disease/condition develops, the sequence of events through the progression of the disease or condition
  • Manifestations- Visible and invisible observations that the disease or condition is present. This begins on a cellular level

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Etiology

  • Extrinsic
  • Intrinsic
  • Psychogenic
  • Idiopathic
  • Multifactorial

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Etiology: Extrinsic

  • Microorganisms

  • Bacteria

  • Fungi

  • Viruses

  • Physical agents

  • Temperature

  • Electricity

  • Ionizing radiation

  • UV radiation

  • Ultrasound

  • Microwaves

  • Lasers

  • Chemical agents

  • Poison

  • Acid

  • Venom

  • Drugs

  • Lead

  • Mercury

  • Mechanical agents

  • Knives

  • Guns

  • Motor vehicle accidents

  • Bad luck

  • Nutritional deficiencies

  • Scurvy

  • Rickets

  • Excess obesity

  • Iatrogenic

  • Infective endocarditis

  • Hospital infections

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Etiology: Intrinsic

  • Genetic

  • Sickle cell disease

  • Cystic fibrosis

  • Some breast cancers

  • Immunologic

  • Autoimmune

  • Lupus

  • Rheumatoid arthritis

  • Hypersensitivity

  • Allergies

  • Degenerative

  • Osteoporosis

  • Osteoarthritis

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Etiology: Psychogenic

  • Conscious or subconscious reactions or attitudes
  • Posttraumatic stress disorder

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Etiology: Idiopathic

  • Unknown
  • Fibromyalgia

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Etiology: Multifactorial

  •  More than one causative factor
  • Primary hypertension
  • Most cancers

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Risk Factors

  • Genetic

  • Immune system dysfunction

  • Compromised first-line defenses

  • Skin, exocrine

  • Age

  • Lifestyle

  • Stress

  • short/long term

  • Environment

  • Pre-existing conditions

  • Multiple risk factors

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Pathogenesis

  • The sequence of events during which cells or tissues respond to a specific etiologic agent

  • Terminology

  • Incubation period, latent period

  • Sign, symptom, manifestation, complication

  • Exacerbation, resolution, sequela, relapse

  • Morbidity, mortality

  • Prognosis

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Disease Manifestations

  • Begin on a cellular level
  • Cellular adaptation
  • Cellular injury
  • Cellular death

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Cellular Adaptations

  • Adaptive cellular changes occur often and for both normal and abnormal or pathologic reasons

  • Resolution or return to normal

  • Continued injury

  • Cell death

  • Atrophy: Abnormal decrease in the number of cells in an organ or tissue

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  • Hypertrophy: An enlargement of a tissue or organ resulting from an increase in the size of its individual cells but not in the number of cells

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  • Hyperplasia: An enlargement of a tissue or organ resulting from an increase in the number of cells; the result of increased cell division

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  • Metaplasia: The transformation of one differentiated cell type to another differentiated cell type. The change from one type of cell to another may be part of a normal maturation process, or caused by some sort of abnormal stimulus

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  • Dysplasia: Disorder growth; alteration in size, shape, and organization of adult cells. A premalignant condition of the oral cavity

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Reversible Cellular Injury

  • Free radical injury
  • Hypoxic cell injury
  • Intracellular imbalance of calcium

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Irreversible Injury

  • Apoptosis: The programmed cell death as part of an organism’s growth or development.  The cell follows a set of instructions that tell them how to die. These instructions allow the cell to die without causing inflammation or damaging any of the healthy cells around it. Apopsis is a process that allows the body to remove old and damaged cells. It is very common in developing embryos

  • Necrosis: The pathologic death of one or more cells, or part of tissue, or an organ that results from irreversible damage to cells. It is a uncontrolled type of cell death that happens before the end of the natural lifespan of the cell

  • Caseous necrosis: Unique form of cell death in which the tissue maintains a cheese-like appearance

  • Coagulative necrosis: Type of necrosis caused by ischemia (sudden cessation of blood flow) or infarction (obstruction of blood supply to an organ or region of tissue causing local death of the tissue

  • Liquefactive necrosis: Type of necrosis which results in a transformation of

the tissue into a liquid viscous mass

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