1 Introduction to Pathology

• Pathology is the discipline that involves the investigation of the causes of disease and associated changes at the levels of cells, tissues, and organs.
• Classifications of pathology

  • General pathology – broad and complex.
  • Systemic pathology – description of a specific diseases in a targeted organ.
• Branches of pathology

  • Anatomic pathology
  • Clinical pathology
  • Forensic pathology
  • Molecular pathology
• Health refers to the "state in which an individual is living in complete harmony with his environment“
• Disease is the state in which an individual exhibits physiological, anatomical, histological deviation from the normal.
• Etiology is the origin of a disease; why a disease arises.
• Pathogenesis describes how etiologic factors trigger cellular and molecular changes that give rise to a specific functional and structural abnormality; how a disease develops
• Morphologic changes describes structural changes that results from the disease (both macroscopic and microscopic).
• Functional derangement is the consequences of the morphologic change.
• Congenital Defects are abnormalities of structure, function, or body metabolism that are present at birth; abnormalities may lead to mental / physical disabilities or are fatal.
• Inherited/Genetic Disorders

  • it is caused by abnormalities in the genetic makeup at the chromosomal or genetic level; inherited from parents.
  • Developmental diseases develop during embryonic or fetal development.
• Biologic agents are usually classified by the type of offending organism; infections and diseases caused are infectious diseases and can cause cell destruction directly or toxins elaborated by infectious agents.
• Immunologic Dysfunction can be caused by aberrations to the immune system.
• Immunologic dysfunctions

  • Hypersensitivity reaction – exaggerated immune response to an antigen.
  • Immunodeficiency – deficiency of a component of the immune system which leads to increased susceptibility to different diseases.
  • Autoimmunity – abnormal (exaggerated) immune reaction against the self-antigens of the host.
• Metabolic Derangements are disorders that stem from a deficiency in the activity of an enzyme involved in the synthesis or breakdown of intermediates in the metabolism of carbohydrates, fats or proteins.
• Degenerative Changes & Inflammatory Disease are caused by forces or agents that destroy cells, or intercellular substances, deposit abnormal substances in tissues or cells, or cause the body to injure itself by means of the inflammatory process.
• Malignancy is a disease, including but not limited to cancer, in which the progress is extremely rapid and generally threatening or resulting in death within a short time.
• Direct physical injury is called Trauma.
• Nutritional excesses or deficits are any of the nutrient-related diseases and conditions that cause illness in humans.
• Pathogenesis are sequence of events that describes how the cell and tissues respond to stimulus or pathogen.
• Morphology is the structural and associated functional changes in cells, tissues and organs that are characteristic of the disease or condition.
• Signs are objective findings as perceived by an examiner (physician).
• Symptoms are functional manifestations or evidence of a disease process (patients).
• Lesions are visible changes produced by a disease in the tissues or organs; usually local abnormalities which could be benign, cancerous, gross, occult, or primary.
• Exacerbations are a sudden increase in the severity or seriousness of the signs and symptoms during the course of disease.
• Remissions means that severity of disease become less intense at a time.
• Complications are unfavorable conditions that arise during the course of a disease.
• Pneumonia is most common complication in patients that are longer admitted in hospital.
• Sequelae is the remote aftereffects (consequences) produced by a disease.
• Diagnosis is the assimilation of information from patient’s history, physical examination, and laboratory findings to identify the condition causing the disease.
• Prognosis is the prediction of the likely or expected development of a disease, including whether the signs and symptoms will improve or worsen, or remain stable over time