Dead tissue. Tissue that has lost its blood supply dies and becomes necrotic. Parts of cancers outgrow their blood supply and become necrotic. Radiation can cause a loss of blood supply to a tissue and it will become necrotic. Necrotic tissue is usually infected and has an odor.
Cell death. Loss of cells, tissues, or parts of a structure or organ due to the progressively degrading actions of certain enzymes, such as the degradation of DNA within the nucleus of dying cells. Necrosis may result from a loss of blood supply (ischemia), infection, excessive exposure to ionizing radiation, certain chemicals, or extreme temperatures.
A localised and rapid destruction of a cell or more often a group of cells and a consequent quick death of those which are in contact with or form part of a living tissue; rot and canker are examples of necrotic symptoms. Cell death (used particularly for death of cells in a focal point in a multi-cellular organism) due to anoxia or local toxic or micro-biological action.
(nec roh´ sis) • Tissue damage resulting from cell death. Negative control • The situation in which a regulatory macromolecule (generally a repressor) functions to turn off transcription. In the absence of a regulatory macromolecule, the structural genes are turned on.
death of tissue accompanied by dark brown discoloration, usually occurring in a well-defined part of a plant, such as the portion of a leaf between leaf veins or the xylem or phloem in a stem or tuber.
A form of cell death resulting from anoxia, trauma, or any other form of irreversible damage to the cell; involves the release of toxic cellular material into the intercellular space, poisoning surrounding cells.
Passive or unregulated cell death, in which cells lyse and deposit degradative and antigenic cell constituents into the surrounding tissue. Necrotic cell death, in contrast to apoptosis, often provokes an inflammation reaction.
The word pathologists use when there is death of part or all of a tissue or organ due to an outside factor, such as cutting off the blood supply. If apoptosis is regarded as cellular suicide, then necrosis could be called cellular murder. Important examples include aseptic necrosis of the femoral head and the loss of an ovary from untreated torsion.
liquefaction of a tissue. The necrosis of atheromatous plaque brings about the formation of a cavity. Such a cavity fills up with liquefied tissues and plaque debris. As long as necrosis remains confined to the plaque, there is no risk of neurological incident. When necrosis extends toward the carotid artery lumen, and if the necrosed cavity ruptures into the arterial circulation, plaque debris is carried away in the blood flow toward the cerebral arteries, which can be occluded.
Process of cell death that results from massive disruption of normal cellular homeostasis, that is so disruptive that the cells cannot repair themselves and then die. This is a common form of cell death following injury to tissue.
A common form of cell death caused by external insults to cellular integrity; in some cases, necrosis may spread from cell to cell to damage many neighboring cells. Necrotic cells show early swelling in cytoplasmic organelles and the nucleus, lytic activity in the cytoplasm, and late changes in chromatin, while the cell gradually swells in volume before dying ( Hengartner, 1997). See Apoptosis See Phagocytosis