Pathophysiology: Chapter 2 Altered Cellular and Tissue Biology

Objectives - correct answer Describe the following cellular adaptations: atrophy, hypertrophy, hyperplasia, dysplasia (atypical hyperplasia), and metaplasia. Identify and describe the mechanisms of cellular injury for the following causes: hypoxia, chemicals, free radicals, infectious agents, asphyxial injuries, immunologic and inflammatory responses, genetic factors, nutritional imbalances, and physical trauma. Compare and contrast cellular necrosis with apoptosis. Cellular Adaptation - correct answer Is the cell's response to escape and protect itself from injury. Cells have 2 options: Adaptation Death Atrophy - correct answer decrease in cell size Physiologic: Occurs with early development, similar to the thymus Pathologic: Results from decreases in workload, use, pressure, blood supply, nutrition, hormonal stimulation, and nervous stimulation Cerebral atrophy, muscle atrophy/bedrest Disuse Decreased protein synthesis, increased protein catabolism, or both Hypertrophy - correct answer Increase in cell size Caused by increased work demand or hormones -Trigger signals: Mechanical and trophic Physiologic -Skeletal muscle and exercis Pathologic Cardiac hypertrophy Amounts of protein in the plasma membrane, endoplasmic reticulum, microfilaments, and mitochondria are increased. Hyperplasia - correct answer Increase in cell number -Caused by increased rate of cellular division Physiologic Compensatory: Allows organs to regenerate (e.g. liver regeneration) Hormonal: Replaces lost tissue or supports new growth (e.g. endometrium is estrogen-responsive) Pathologic: abnormal proliferation of normal cells in response to excessive hormonal stimulation or growth factors on target cells e.g. pathologic hyperplasia of the endometrium, acromegaly Metaplasia - correct answer Reversible replacement of one mature cell type by another less mature cell type Change of cell type Is the reversible replacement of one mature cell by another less mature cell type. Is a reprogramming of stem cells. Dysplasia - correct answer Abnormal cellular growth; is not a true cellular adaptation but rather an atypical hyperplasia (more likely to become cancerous) Refers to abnormal changes in the size, shape, and organization of mature cells. Can be called atypical hyperplasia. Does not indicate cancer. Ischemia can lead to : - correct answer atrophy of cells Thymus - - correct answer decrease in hormone leads to atrophy of the thymus gland with age Spinal muscular atrophy Body building - - correct answer increase muscle cell SIZE Which information is correct regarding pathologic hyperplasia? Pathologic hyperplasia: a. Produces an abnormal proliferation of abnormal cells. b. Is an adaptive mechanism that enables organ regeneration. c. Increases cell size. d. May occur in response to growth factors. - correct answer d Metaplasia examples - correct answer Examples: Replacement of normal bronchial columnar ciliated epithelial cells by stratified squamous epithelial cells with airway irritation Cervical metaplasia with recurrent HPV infections Intestinal metaplasia and reflux disease Smoking Breast tissue across the lifespan - correct answer Breast tissue undergoes adaptation to trophic (hormonal) signals Puberty - correct answer breast tissue hyperplasia Pregnancy - correct answer breat tissue hypertrophy Breastfeeding - correct answer mammary hyperplasia Menopause - correct answer breast tissue atrophy - homeostasis - correct answer Cells maintain a steady state Cell stress leads to adaptation - - correct answer new homeostatic state with preservation of function Stress beyond capability of adaptation leads - correct answer to cell injury Cell injury is - correct answer reversible within certain limits then become irreversible leading to cell death 2 types of cell death: - correct answer necrosis and apoptosis Causes of cell injury and death - correct answer Toxins: chemical, pathogenic Infections Physical Injury: mechanical, chemical, thermal Serum deficit injury: nutrition, hydration, oxygenation Four biochemical themes - correct answer Adenosine triphosphate (ATP) depletion Oxygen and oxygen-derived free radicals Intracellular calcium and loss of calcium steady state Defects in membrane permeability Cellular injury can lead to cell death by: - correct answer 1. Decreased ATP production 2. Failure of active transport mechanisms (sodium-potassium [Na+/K+] pump) 3. Cellular swelling 4. Detachment of ribosomes from endoplasmic reticulum 5. Cessation of protein synthesis 6. Mitochondrial swelling from calcium accumulation 7. Vacuolation 8. Leakage of digestive enzymes from lysosomes; autodigestion of intracellular structures 9. Lysis of the plasma membrane 10.Death Ischemia - correct answer The initial insult in hypoxic injury is usually ischemia Ischemia= the cessation of blood flow into vessels that supply the cell with oxygen and nutrients This is usually rapidly followed by anoxia Anoxia - correct answer lack of oxygen in the tissues Consequences of anoxia: - correct answer Cellular responses -Decrease in ATP, causing failure of the Na+/K+ pump and sodium-calcium exchange -Eventual cellular swelling Risk of reperfusion injury also possible -Injury from the high levels of free radicals generated by the injured tissue Oxidative Stress - - correct answer reactive oxygen species (ROS) Toxic oxygen molecules or radicals that are formed by the reaction between oxygen (O2) and water (H2O) during mitochondrial respiration ROS species include - correct answer superoxide, hydrogen peroxide, hydroxyl radical, and peroxynitrite Call damage can result from too many - correct answer ROS or not enough available enzymes, including catalase to convert these radicals to less harmful substances Cellular damage resulting from ROS is called - correct answer free radical injury ROS implicated in many disease processes - correct answer Heart disease, diabetes, cancers Mechanisms for inactivation of free radicals - correct answer Antioxidants Enzymes Mitochondrial oxidative stress - correct answer Mitochondria are source of ROS Mitochondria are target of ROS Homeostasis is important Toxic molecules or radicals that are formed from the reaction between oxygen and water during mitochondrial respiration are called: a. Superoxide dismutase b. Peroxidase c. Reactive oxygen species (ROS) d. Antioxidants - correct answer c Cellular accumulations (infiltrations) - correct answer Harm cells by "crowding" organelles and by causing excessive (and sometimes harmful) metabolites Lipids and carbohydrates - correct answer Usually affects the liver (e.g., fatty liver)