Cell Injury (MPTH211) PDF

College of Medicine Code: MPTH211 Level 3 Cell injury-1 Dr. Sara Elshiekh Assistant professor of Pathology AL- RAYAN COLLEGES Attendance  Objectives: learning outcomes (LOCs) ; At the end of this sessio...

College of Medicine Code: MPTH211 Level 3 Cell injury-1 Dr. Sara Elshiekh Assistant professor of Pathology AL- RAYAN COLLEGES Attendance  Objectives: learning outcomes (LOCs) ; At the end of this session, the students will be able to: o Understanding the general principles, terminology and basic concepts of pathology. o Identify the, mechanisms & types of cell injury o Enumerate the causes of cell injury o Describe the morphological changes of cell injury References: ROBBINS ESSENTIAL PATHOLOGY https://drive.google.com/file/d/1kXeLoPylqPedakrjS6bKH0FH53rbKswb/view?usp=sharing What is pathology? Definition: Pathology is defined as a branch of medical science that studies the nature, causes, effects, and consequences of disease. Aspects of pathology: Etiology or cause Pathogenesis Morphologic Changes Clinical Manifestations Prognosis Fate Complications  Etiology or cause of disease: 1-Predisposing factors; e.g., cold weather, low socioeconomic status, malnutrition, extremes of age. 2-Determining factors; e.g., infectious agents. Infections: e.g., bacterial, viral, parasitic, fungal Aspects of Physical: Excess heat or cold, irradiation etc.… pathology Chemical: e.g., concentrated acids and alkalis, toxins, drugs Genetics: Some disease are caused by certain chromosomal abnormalities Immune mediated: e.g hypersensitivity reactions and autoimmune diseases Pathogenesis: it means mechanism of disease development & progression, i.e the chain of events leading to that disease. Morphologic Changes (morphology); includes: A- Gross picture: naked eye appearance = macroscopic picture B- Microscopic picture: histopathology Morphologic Changes Gross picture/ macroscopic picture Microscopic picture  Clinical Manifestations: (signs & symptoms) 1.SIGN: A medical sign is an indication of some medical fact or characteristic that detected by a physician during a physical examination 2.SYMPTOM: the subjective experiences, such as fatigue, reported by patients. Complications: unfavorable consequences of a disease. E.g. liver cirrhosis can be complicated by liver cell failure. Prognosis: Prediction of the probable outcome of a disease. Fate: The end result of the disease either by cure or by death of the patient, disease progression, or regression or occurrence of complications.  Cell Injury If the cells exposed to stress, they undergo certain changes called cell injury. The affected cells may recover from the injury (reversible) or may die (irreversible). Causes of Cell Injury Genetic. Physical. Chemical. Biological. Hypoxia Nutritional. Immunological. Mechanisms of Cell Injury Mitochondrial damage: ATP depletion → failure of energy dependent cellular functions Influx of calcium: activation of enzymes that damage cellular components Accumulation of reactive oxygen species: modification of cellular proteins, lipids, nucleic acids Increased permeability of cellular membranes: May affect : -Plasma membrane Lysosomal membranes- - Mitochondrial membranes Accumulation of damaged DNA: Triggers apoptosis Reversible Cell Injury Patterns of Reversible Cell Injury 1-Cellular swelling (hydropic degeneration). 2-Fatty change Cellular swelling This pattern of nonlethal injury is sometimes called hydropic change or vacuolar degeneration. Mechanism: Cellular swelling is the result of failure of energy-dependent ion pumps in the plasma membrane, leading to an inability to maintain ionic and fluid homeostasis. Microscopic examination may reveal small, clear vacuoles within the cytoplasm Cellular swelling small, clear vacuoles within the cytoplasm Microscopic small, clear vacuoles within Hydropic change- kidney  Fatty change Occurs in hypoxic injury and in various forms of toxic or metabolic injury and is manifested by the appearance of small or large lipid vacuoles in the cytoplasm (steatosis). It is principally encountered in cells participating in fat metabolism (e.g., hepatocytes). Grossly :The liver is enlarged and yellow. The cut surface is pale yellow and greasy The liver is enlarged and yellow appearance of small or large lipid vacuoles in the cytoplasm of The cut surface is pale yellow and greasy hepatocytes (steatosis).  Irreversible cell injury Mechanism:- Starts as reversible cell injury more severe damage…….death Cell death due to: 1. membrane rupture. 2. Autolysis by lysosomal enzymes. A, Normal kidney tubules with viable epithelial cells. B, Early (reversible) ischemic injury showing increased eosinophilia of cytoplasm, and swelling of occasional cells. C, Necrotic (irreversible) injury of epithelial cells, with loss of nuclei and fragmentation of cells and leakage of contents.  Outcome of Cell Injury Injury Normal Reversible Diseased cell cell Irreversible Adaptive Adaptive Death cell Session Evaluation