What are senescent cells 30 and what are senescent cells

A process of change in which cell proliferative capacity and physiological functions gradually decline over time. Senescent cells are senescent cells that undergo significant changes in morphology, cell shrinkage, increased plasma membrane permeability and fragility, decreased number of mitochondria, and chromatin consolidation and breakage.

It is a cell that dies normally, not a cell that dies due to cancer, viral erosion or genetic mutation.

It cannot be self-replicated and updated.

Cellular senescence is the proliferation of cells over time in the process of performing vital activities.

Changes with a gradual decline in differentiation ability and physiological function. The life course of a cell goes through several stages: undifferentiated, differentiated, growing, maturing, aging, and dying. Aging and dying cells are taken by the body's immune system.

At the same time, new cells are constantly being generated from the corresponding tissues and organs to compensate for the aging and death of cells.

Apoptosis. Different from cell necrosis, apoptosis is not a passive process, but an active process, which involves the activation, expression and regulation of a series of genes.

Significance of senescence and apoptosis of cells

Apoptosis and cell proliferation are both basic phenomena of life and basic measures to maintain the dynamic balance of cell number in the body. In the embryonic development stage, the redundant and mission-completed cells are removed through apoptosis, which ensures the normal development of the embryo; In adulthood, senescent and diseased cells are removed through apoptosis, ensuring the health of the body.

The basis of body aging is the aging of the cells that make up the body at the level of the whole, system or organ, but it does not mean that all the cells that make up the body have undergone aging. Cell senescence and death and the growth and replacement of new cells in normal life activities are the inevitable laws of metabolism, and they also avoid tissue structure.

Degeneration and the accumulation of senescent cells allow the body to delay overall aging.

The above content refers to Encyclopedia - Cellular Senescence.

The above content refers to Encyclopedia - Apoptosis.

Many people don't want to age, because as they get older, many diseases will occur, the body's metabolism will slow down, the organs will age, and the appearance will become old and ugly, the hair will turn gray, and age spots will appear. People will age because the cells in the human body will also age, so what are the characteristics of senescent cells? The first is that the moisture in the thin bag becomes less, which is reflected in the dryness.

There is also a decrease in the active enzymes of the sachets, which leads to graying of the hair. There is also the precipitation of melanin in the cells, which leads to the appearance of age spots.

1.One of the characteristics of senescent cells is that there is less water inside the cells.

When there is less water in the cell, the cell shrinks and the cell becomes smaller, which slows down the cell's metabolism. The slowdown of the body's metabolism will lead to the drying of the person, which will lead to the aging of other organs of the body, and the whole person will look old.

2.The second characteristic of senescent cells is the reduced activity of intracellular enzymes.

The aging of a healthy cell means that the activity of some biological enzymes in the cell will also decrease, which is embodied in the graying of human hair, and the aging of melanocytes in the hair is due to the decrease in the activity of tyrosinase in the cell, which will lead to a decrease in the synthesis of melanin in the human body, which will lead to a decrease in the synthesis of black hair, which fully reveals why the elderly have gray hair.

3.The third characteristic of senescent cells is the accumulation of pigment in cells.

If the cell senescent and the volume becomes smaller, then the pigment in the cell will also accumulate, so the concentration of such a cell will be greater, which will hinder the exchange of substances in the cell, thus affecting the normal physiological function of the cell. This is fully reflected in why the elderly have age spots. Age spots are due to the pigment in the cells, which accumulate gradually due to cellular aging.

In short, cellular senescence is a physiological process that occurs within cells, and senescent cells undergo significant changes in morphology, structure, and function. We should pay attention to health preservation, pay attention to healthy diet, drink more water to promote metabolism, exercise appropriately, increase cell activity, and slow down the occurrence of aging.

Do you know the various characteristics of cellular senescence?

The amount of water in the cells decreases, as a result the cells shrink, become smaller in size, the rate of cell metabolism slows down, and the activity of many enzymes in the cells decreases.

Pigment in cells accumulates as cells age.

The respiration rate of cells slows down, the volume of the nucleus increases, the nuclear membrane folds inward, the chromatin shrinks, and the permeability of the cell membrane is deepened by staining, which reduces the material transport function.

1. Excessive macromolecular cross-linking is a major factor of aging, such as DNA cross-linking and collagen glue can damage their function and cause aging.

2. After the accumulation of cell metabolites to a certain amount, it will harm the cells and lead to the aging of the cells.

3. Free radicals contain unpaired electrons, which are highly reactive, which can trigger chain radical reactions, cause denaturation and cross-linking of DNA, proteins and lipids, especially macromolecular substances such as polyunsaturated fatty acids, and damage DNA, biological membranes and important structural and functional proteins, thereby causing the occurrence of various phenomena of aging.

4. The mitochondria that exist in the cells to provide energy are prone to mutations, and the accumulation of mutations is likely to be one of the reasons for the aging of the human body.

Studies have shown that the nucleus, cytoplasm and membrane of senescent cells have obvious changes

Intracellular water decreases, the volume becomes smaller, and the rate of metabolism slows down;

decreased activity of intracellular enzymes;

Pigments accumulate within the cells;

Intracellular respiration slows down, the nucleus increases in size, the nuclear membrane folds inward, chromatin shrinks, and the color darkens. The number of mitochondria decreases and the volume increases;

The permeability function of the cell membrane is changed, which reduces the function of material transport.

Morphological changes. In general, the various structures of aging cells are degenerating. The morphological changes of senescent cells are manifested in:

1. Nucleus: enlarged, deeply stained, and there are inclusions in the nucleus.

2. Chromatin: condensation, condensation, fragmentation, dissolution.

3. Plasma membrane: viscosity increases and fluidity decreases.

4. Cytoplasm: pigment accumulation, vacuole formation.

5. Mitochondria: decrease in number and increase in volume.

6. Golgi apparatus: fragmentation.

7. Nissl body: disappears.

8. Inclusions: glycogen reduction, fat accumulation.

9. Nuclear membrane: invagination.

Changes at the molecular level.

1. DNA: In general, DNA replication and transcription are inhibited during cell senescence, but there are also individual genes that will be abnormally activated, telomeric DNA is lost, mitochondrial DNA is specifically missing, DNA oxidation, breakage, deletion and cross-linking, and the degree of methylation is reduced.

2. RNA: mRNA and tRNA content decreased.

3. Protein: The content decreases, and the intracellular protein undergoes glycosylation, carbamylation, deamination and other modification reactions, resulting in the decrease of protein stability, antigenicity, and digestibility, and free radicals break protein peptides, cross-link and denature. Amino acids change from left-handed to right-handed.

4. Enzyme molecules: the active center is oxidized, the metal ions Ca2+, Zn2+, Mg2+, Fe2+, etc. are lost, the secondary structure, solubility, and isoelectric point of the enzyme molecule are changed, and the total effect is enzyme inactivation.

5. Lipids: unsaturated fatty acids are oxidized, causing cross-linking between membrane lipids or lipoproteins, and reducing the fluidity of the membrane.