2. Cell necrosis is another form of programmed cell death, which has important physiological functions, including triggering inflammatory reaction. When apoptosis cannot occur normally and cells must die, necrosis is adopted as the "alternative" way of apoptosis. For a long time, cell necrosis has been regarded as passive death caused by pathology, such as physical or chemical injury factors, hypoxia and malnutrition. The membrane permeability of necrotic cells increases, which leads to cell swelling, organelle deformation or swelling, and there is no obvious morphological change in the early nucleus, and finally the cells rupture. Cell lysis releases inclusions, which often causes inflammatory reactions; In the process of healing, it is often accompanied by fibrosis of tissues and organs, forming scars.
3. Cell senescence refers to the process in which cells' proliferation and differentiation ability and physiological function gradually decline with the passage of time in the process of life activities. Cell senescence refers to the process in which cells' proliferation and differentiation ability and physiological function gradually decline with the passage of time in the process of life activities.
4.
Because of carcinogens, cells can't divide normally, but become malignant proliferating cells that are not controlled by organic substances and continue to divide.
Basic features: 1. Cell division and differentiation are out of control and have the ability of infinite proliferation. The main reasons are: loss of contact inhibits growth; At the same time, it can secrete growth factors that stimulate its own proliferation and promote its own division; Lost the programmed descent mechanism; The gap junction is lost, which leads to the loss of communication between cells in metabolism and division and differentiation.