One: the cytoplasm is large, the chromatin is concentrated and the staining is aggravated. One: the water content of somatic cells decreases, the volume decreases and the metabolic rate slows down. Another one: melanin in somatic cells slowly accumulates and increases. Two lows: partial enzymatic reactions are reduced, and the material transport function of the membrane is reduced.

Cell senescence refers to the process in which the proliferation and differentiation ability and physiological function of cells gradually decline with the passage of time in the process of life activities. The life course of cells goes through several stages: undifferentiation, differentiation, growth, maturity, aging and death. Aging dead cells are destroyed by the body's immune system, and corresponding tissues and organs constantly produce new cells to make up for aging dead cells. The dynamic balance between cell aging and death and new cell growth is the basis of maintaining normal life activities of the body.

Features:

1. The nucleus and nuclear membrane are depressed, which eventually leads to the disintegration of nuclear membrane, the change of chromatin structure and the increase of the number of hyperdiploid and abnormal polyploid cells.

2. The brittleness of cell membrane increases, the selective permeability decreases, and the types and quantity of membrane receptors and the sensitivity to ligands change. Lipfuscin accumulates in cells, and many organelles and intracellular structures degenerate.

3. The cell cycle is stagnant, the cell replication ability is lost, the responsiveness to mitogenic stimulation is weakened, and the responsiveness to pro-apoptotic factors is changed.

4. The intracellular enzyme activity center is oxidized, the enzyme activity is reduced, and protein synthesis is reduced.