04 - Cell Injury and Repair/Cellular Death Flashcards
Describe and discuss the general causes of cellular injury. (Mnemonic)
Adaptation to stress is not sufficient.
“Please Give Our Cells No Irreversible Injury”
Physical: Electricity, radiation, barotrauma, mechanical stress, burns, excessive cold.
Genetic: DNA alteration that is either inherited or acquired.
Oxygenation: Hypoxia, anoxia (depletion of O2), too much O2.
Chemical: Drugs and toxins can disrupt biochemical cell function or physical cell structure.
Nutritional: Deficiency or excess in vitamins, minerals, or proteins.
Infectious: By an organism, molecular components of an organism (toxins), immune response of organism.
Immunologic: Deficient or exuberant immune response. Inability to distinguish self from non-self (autoimmune).
Distinguish between reversible cell injury and irreversible cell injury.
Reversible: Leading to some level of remaining function.
Irreversible: Resulting in cell death.
Give examples of cellular injury related to free radicals.
Free radicals are unstable, reactive oxygen species that have single unpaired electrons in the outer orbit. Free radicals can react with lipids (in the plasma membrane and other organelle membranes), modify proteins (reacting with amino acid side chains, promote protein-protein cross linkages, cause oxidation of protein backbones, damage active sites, disrupt conformation or structural proteins, enhance proteasomal degradation), and cause lesions in DNA (single and double strand breaks, DNA cross linking, formation of adducts, can cause cell aging and malignant transformation).
Define hypoxia
Less than normal amount of oxygen reaching cells.
Define hypoxemia
Less than normal amount of oxygen in blood.
Define ischemia
Diminished blood supply to cell or tissue.
Define anoxia
Complete deprivation of oxygen due to no blood supply to tissue; leads to infarct.
Define induction (of cell injury)
Plasma membrane loses permeability. Sodium and water come into cell, potassium out of cell. Cell swells and calcium enters cell.
Define induction (of cell death)
Influx of calcium causes membrane disruption leading to hydrolyzing of proteins and DNA cleavage. Feedback mechanism leads to death.
Define effector
Molecules which selectively bind to cells in process of apoptosis to induce degradation by phagocytosis from macrophages.
Define degradation
The breakdown of unnecessary or dysfunctional cellular components by lysozymes. In cell death it is an adaptive response to stress which promotes survival of surrounding cells.
Define phagocytic
Cells that take particles and substances into self for destruction (eg macrophage, neutrophils).
Define degeneration
Mild or reversible structural changes of a cell. Breakdown that leaves some loss of function.
Define regeneration
Replacement of lost cells and tissue whose function is so similar to original lost cells that replacements are considered identical. Reproduction of same tissue that was lost.
- Describe the morphologic pattern of single cell necrosis/apoptosis
Nuclear chromatic changes are pyknotic (dark and condensed), the cell shrinks and organelles become compact, cell membrane remains intact for a longer duration (than necrosis) with cell fragmentation. Because preprogrammed, quickly removed by phagocytes/macrophages.
Describe the morphological patterns of coagulative necrosis and relate the to common pathogenic mechanisms
Architecture of cell maintained with formation of gelatinous substance in dead tissue (eg infarct, ischemia).
Describe the morphological patterns of liquefactive necrosis and relate the to common pathogenic mechanisms
Cell transformed into thick liquid without defined shape (eg bacterial/fungal infections, brain hypoxia).
Describe the morphological patterns of caseous necrosis and relate the to common pathogenic mechanisms
Cell becomes amorphous and loses outline. Surrounded by granulomatous inflammatory border (eg tuberculosis, fungal infections).
Describe the morphological patterns of fat necrosis and relate the to common pathogenic mechanisms
Necrosis of fat tissue where cell maintains its outline. Surrounded by white, chalky area (eg pancreas and other fatty tissue – breast, abdomen, subcutaneous tissue).
Describe the morphological patterns of fibrinoid necrosis and relate the to common pathogenic mechanisms
Cell loses outline and becomes homogenous and pink; resembling fibrin (eg blood vessels of autoimmune pts).
Describe the morphological patterns of gummatous necrosis and relate the to common pathogenic mechanisms
Form of granuloma (eg spirochete infections).
Describe the morphological patterns of hemorrhagic necrosis and relate the to common pathogenic mechanisms
Caused by blockage of venous drainage of organ or tissue.
Describe the signs and symptoms of dry gangrene
Tissue appears black, dry, shriveled with sharp demarcation from viable tissue.
Describe the signs and symptoms of wet gangrene
Tissue appears swollen, dark red, liquefied, foul odor present and obscured border from viable tissue.
Describe the signs and symptoms of fat saponification
White, chalky areas seen within fat indicating fat necrosis.
Describe the signs and symptoms of loss of function (regarding cell death)
Cell death affecting tissue function.
Define atrophy in regards to cellular adaptation to injury in tissues
Decrease in size or number of cells.
Define hypertrophy in regards to cellular adaptation to injury in tissues
Enlargement due to an increase in the size of cells.
Define hyperplasia in regards to cellular adaptation to injury in tissues
Enlargement due to an increased number of cells.
Define metaplasia in regards to cellular adaptation to injury in tissues
Reversible change from one type of fully mature cell to a different type of mature cell not usually found in tissue involved.
Define dysplasia in regards to cellular adaptation to injury in tissues
Partially reversible change from a mature cell to a cell with abnormalities in both differentiation and maturation.
Define anaplasia in regards to cellular adaptation to injury in tissues
Structural differentiation loss within cell or group of cells.
