Introduction To Pathology And Cellular Injury PDF

Introduction To Pathology And Cellular injury By: Dr. Zheen Othman Lecturer of pathology M.B.Ch.B, FKBMS (Pathology) Hawler Medical University College of Medicine Objectives: Definition of pathology  Cores of pathology Causes of cell injury PATHOLOGY Pathos (suffering) Logos (st...

Introduction To Pathology And Cellular injury By: Dr. Zheen Othman Lecturer of pathology M.B.Ch.B, FKBMS (Pathology) Hawler Medical University College of Medicine Objectives: Definition of pathology  Cores of pathology Causes of cell injury PATHOLOGY Pathos (suffering) Logos (study) PATHOLOGY Is the scientific study of disease or is the study of structural (morphological) and functional(physiological) abnormalities that are expressed as diseases of organ and system PATHOLOGY GENERAL SYSTEMIC General Pathology It explores and explains the development of basic pathologic mechanisms:  Cell injury.  Inflammation, repair and healing.  Haemodynamic (circulatory) disorders.  Neoplasia.  Immunopathology  Genetic disorders  Infection Systemic Pathology The pathologic mechanisms discussed in the General Pathology are related to various organ systems:  Cardiovascular System (CVS)  Respiratory System  Alimentary System (GIT)  Hepatobiliary System and Pancreas  Urinary System  Male & Female Genital Tract Systems  Central nervous system (CNS)  Musculoskeletal system  Dermatopathology (SKIN) Cores of pathology 1-Etiology 2-Pathogenesis (sequence of events at the organ, cellular, ultrastructural, and molecular levels, from initial stimulus to the ultimate expression of the disease.) 3-Morphologic changes (Macro- & microscopical changes) 4-Signs & symptoms ( Functional changes)  Cellular Responses To Stress And Noxious Stimuli Normal cell is in a steady state “homeostasis” Cells constantly adjust structure and function to accommodate changing demands and extracellular stress. But within a relatively narrow range of physiologic parameters. Change in homeostasis due to prolonged stimuli injury Functional definition of disease Abnormal homeostasis Causes of Cell Injury Oxygen Deprivation Physical Agents Chemical Agents and Drugs Infectious Agents Immunologic Reactions Genetic Derangements Nutritional Imbalances O2 insufficiency (↓PO2) which impairs aerobic respiration & the ability to produce ATP. This is a common cause of cell death.  a. Hypoxia- lack of O2 results in decreased aerobic respiration  b. Ischemia- lack of O2 & metabolic substrates A.Hypoxia Lack of O2 results in decreased aerobic respiration (Too little available oxygen in the blood ) as in: Reduced blood flow (ischemia) Inadequate oxygenation of the blood due to cardiorespiratory failure, as in pneumonia, heart failure.  Reduction in the oxygen-carrying capacity of the blood, as in blood loss anemia or carbon monoxide (CO) poisoning. B.Ischemia: Ischemia ("ischemic hypoxia“ ) Loss of arterial blood flow. ↓ O2 & nutrition to tissues Local causes ▫ Occlusion of the arteries that bring in fresh blood ▫ Occlusion of the veins which allow blood to leave, so that fresh blood can flow in Systemic causes ▫ Failure of the heart to pump enough blood Physical Agents Mechanical trauma Extremes of temperature (burns, deep cold) Radiation Electric shock  Chemical Agents and Drugs Drugs & hypertonic concentration of salt (deranging electrolyte homeostasis) Poisons ( arsenic, cyanide, or mercuric salts) Insecticides and Herbicides Air pollutant (carbon monoxide) Occupational hazard (asbestos) Alcohol and Narcotic drugs Infectious Agents Parasites Fungi Bacteria Rickettsiae Viruses Immunologic Reactions Hypersensetivity Anaphylactic reaction to foreign protein or drug Reactions to endogenous self- antigens –autoimmune diseases Nutritional Imbalances Protein-calorie deficiencies Vitamin deficiencies Anorexia nervosa Excesses of lipids (Obesity, Atherosclerosis) Metabolic diseases (Diabetes) Genetics Derangements Congenital malformation (Down’s syndrome) Decreased life of red blood cell (Thalassemia, Sickle cell anaemia)) Inborn errors of metabolism Aging Cellular senescence leads to alterations in replicative and repair abilities of individual cells and tissues. Resulting in a diminished ability to respond to damage and, eventually, the death of cells and of the organism. Summery Pathology is study of diseases by scientific methods. Cores of pathology are etiology, pathogenesis, morphologic changes & clinical features. Causes of cell injury are genetic & acquired causes. Reference Robbin’s basic pathology, 9th edition,2010 Thank You