1) Cells injury and adaptation.ppt

 ‫معلومات‬ ‫عامة عن‬ ‫صورة غالف‬ ‫المقرر‬ ‫المرجع‬ ‫الرئيسي‬ ‫‪: Introduction to‬اســم المقـــرر‬ ‫‪pathology‬‬ ‫‪: BMD15‬رمـــز المقـــرر‬ ‫اسـم الكليـــة‪ :‬الطب و...

 ‫معلومات‬ ‫عامة عن‬ ‫صورة غالف‬ ‫المقرر‬ ‫المرجع‬ ‫الرئيسي‬ ‫‪: Introduction to‬اســم المقـــرر‬ ‫‪pathology‬‬ ‫‪: BMD15‬رمـــز المقـــرر‬ ‫اسـم الكليـــة‪ :‬الطب والعلوم الصحية‬ ‫اسـم القســم‪ :‬العلوم الطبية االساسية‬ ‫اسـم البرنامج‪ :‬الطب والجراحة‬ ‫اســم المـدرس‪:‬د‪.‬مجاهد يحيى نصار‬ ‫‪:‬إيميل المدرس‬ ‫‪[email protected]‬‬ Content Of Lecture 1  Learning Objectives  Upon completing this chapter students should be able to know and understand:  1. Pathology definition.  2. Causes of cell injury.  3- Cellular Response(types) to Injury.  4. Mechanisms of cell injury.  5. Morphology of cell injury  6. Types and morphology of necrosis.  7-Cellular adaptation (atrophy, hypertrophy , hyperplasia and metaplasia).  8- Intracellular and extracellular accumulations:  Fatty change ( steatosis) , Pigments, Calcification and Proteins (amyloidosis).  Pathology is the study of disease.  Patho means disease  Diseases ;defined as an abnormal variation in structure or function of any part of the body.  Pathology of a disease studied under four subdivisions :  1. Etiology  2. Pathogenesis  3. Morphologic changes  4- Functional changes and clinical symptoms and signs.  1. Etiology  means the cause of the disease.  2. Pathogenesis  means the mechanism through which the cause operates to produce the pathological and clinical manifestations.  3. Morphologic changes  It means the structural changes in cells or tissues that occur following the pathogenetic mechanisms.  These changes may be:  a- Gross changes ;changes in the organ that can be seen with the naked eye.  b- Microscopic changes ;changes only be seen under the microscope.   4- Functional changes and clinical symptoms and signs.   In summary, pathology studies:-  Etiology →  Pathogenesis →  Morphologic changes →  Clinical features & Prognosis of all diseases.  1- Hypoxia. 2- Chemical agents. 3- Infectious agents 4- Immunological agents. 5-Genetic defects. 6- Nutritional imbalance 7- Physical agents  1- Hypoxia. Oxygen deficiency is a common cause of cell injury and death. Hypoxia may be due to: a-Inadequate oxygenation of the blood e.g. pneumonia. b-Reduction in oxygen carrying capacity of the blood e.g. anemia. N.B. Ischemia? 2- Chemical agents : Actually any chemical substance can cause cell injury such as glucose or salt , if sufficiently concentrated can cause damage of the osmotic environment and so lead to cell injury and death. - Poisons cause severe damage of the cells by altering membrane permeability, osmotic homeostasis or the integrity of the enzymes. - Even therapeutic drugs can cause cell or tissue injury in a susceptible patient.  3-Infectious agents:  Bacteria ,  viruses,  fungi and  parasites.  4- Immunological agents:  Although the immune system defends the body against foreign materials, the immune reaction can result in cell or tissue injury e.g. a-Allergy to drugs or foreign materials. b-Autoimmune disease(reaction of the immune system against self antigen).  5- Genetic defects:  May result in pathological changes( cell injury)e.g.  a-Congenital malformation associated with Down syndrome.  b-Single amino acid substitution in sickle cell anemia.  6- Nutritional imbalance:  a-Nutritional deficiency remain the major cause of cell injury e.g. protein-calorie insufficiency.  b-Excess of nutrition are also important cause of morbidity and mortality e.g.  Obesity increase risk for type II diabetes mellitus.  Diet rich in animal fat is a risk for atherosclerosis.  7- Physical agents:  Trauma,  temperature,  radiation,  electric shock  Adaptation  Reversible injury.  Irreversible injury. 1-Type , duration and severity of the injury e.g. mild duration of ischemia lead to reversible injury while long duration lead to irreversible injury. 2- Type , status , adaptability and the genetic makeup of the injured cell e.g. skeletal muscle can accommodate complete ischemia for 2-3 hours without irreversible injury, whereas cardiac muscles dies after 20 to 30.minutes  1- ATP depletion.  2- Oxygen deprivation or oxygen free radicals.  3-Loss of calcium homeostasis.  4- Defects in plasma membrane.  5-Mitochondrial damage  It is a reversible changes in the size, number, phenotype, metabolic activity, or functions of cells in response to changes in their environment.  It is a state that lies between normal(unstressed) and th injured(overstressed) cells.  Definition:  Decrease of the size of an organ or tissue due to decrease in the size and /or number of its cells.  Types:  I-Physiological atrophy:  For example: Thymus gland atrophy after puberty.  II. Pathological atrophy:  II. Pathological atrophy:  1-Generalized ;  a-Starvation atrophy  b-Cachexia: terminal stages of malignancy.  2-Localized atrophy;  a-Disuse atrophy: e.g. atrophy of the muscles of casted limb.  b-Neuropathic atrophy affecting paralyzed muscles.  c-Hormonal atrophy e.g. atrophy of the breast after surgical removal of the ovaries.  Definition:  Increase of the size of an organ or tissue due to increase in the size of its cells.  Pure hypertrophy occur in muscles. In other tissues hypertrophy is associated with hyperplasia.  Types:  I-Physiological Hypertrophy:  For example: Muscles of athletes.  II. Pathological Hypertrophy:  This affecting muscles that coat hollow organs due to increased intra-luminal pressure e.g. left ventricular hypertrophy due to aortic stenosis.  Definition:  Increase of the size of an organ or tissue due to increase in the number of its cells.  Types:  I-Physiological Hyperplasia:  1-Hormonal hyperplasia of the mammary gland at puberty, pregnancy and lactation.  2-Compensatory hyperplasia; when one of the a paired organ is surgically removed e.g. kidney, the other one become enlarged due to compensatory hyperplasia.It is usually associated with hypertrophy.  II. Pathological Hyperplasia:  Hormonal hyperplasia as in ovarian dysfunction that lead to excessive eostrogen secretion and lead to mammary and endometrial hyperplasia.  Hyperplasia  Neoplasia 1-Excited by a stimulus 1-May or not excited by 2-Stop on removal of a a stimulus. stimulus. 2- unlimited continuous 3-May have a useful proliferation. function. 3- Has no useful 4-cells of normal function. morphology. Cells may be abnormal. Definition: It is the transformation of one mature tissue into another mature tissue of the same category. It is usually accompanied by some degree of hyperplasia. It is essentially an adaptive process commonly excited by prolonged irritation.  Types: I-Epithelial metaplasia: The commonest form is the squamous metaplasia e.g. transformation of columnar or transitional epithelium into stratified squamous epithelium. It is precancerous. For example:  1-Squamous metaplasia of urinary bladder mucosa in case of bilharziasis.  2- Squamous metaplasia of bronchial mucosa in case of smoker. II. Connective tissue metaplasia  Definition: Epithelia dysplasia means disordered cell proliferation characterized by abnormal cell arrangement and appearance involving part of the epithelial thickness. It is excited by chronic irritation.  Fate: 1-Regression. 2-Progression into Carcinoma insito or carcinoma.  Definition: It is disordered cell proliferation characterized by abnormal cell arrangement and appearance involving the entire thickness of the epithelial thickness. It is a preinvasive precancerous lesion.  Fate: 1-Regression. 2-Most cases progress to invasive carcinoma.