Complete Health Care Guide

Stem cells, a special type of undifferentiated cells that have the ability to divide indefinitely without losing their properties and may produce specialized cells.

Most cells of an adult (we are referring to man and higher mammals) are often multiplied, except for keeping some tissues such as blood and skin. Muscle cells and fat not normally divide. If you get fat, no more cells is that we actually have the same amount of cells, but these have increased in size.

If a lizard loses its tail, it grows back. In mammals do not. If an individual loses a limb, not redeveloped. Regeneration capacity is limited to healing. However, in virtually all tissues there are cells which, although usually not divided, in particular conditions that can proliferate and regenerate tissue. Artificially has been that these cells have the capacity to reproduce and generate various other tissues, and are called stem cells.

Let us now see the development of an embryo to better understand what are the stem cells.

Embryonic development

The zygote formed after fertilization of an egg by a sperm cell is able to generate a new complete individual. It is, therefore, a totipotent cell, capable of producing a complete specimen with all its tissues.

Among the first to fourth days of embryonic development, the original cell is divided into several more cells. Each of these cells, if separated from the rest, is able to produce a complete individual. They are also totipotent.

From the fourth day of human embryonic development the blastocyst is formed. The blastocyst is composed of two cell types and a large inner cavity:

- Outside layer forms the placenta and embryonic envelopes. Is the trophoblast.
- Cell mass, form all tissues of the human body. Embryoblast called.
- The cells of a blastocyst and are totipotent, since one of these cells is no longer able to generate a complete individual. – The cells of the inner cell mass of pluripotent cells blastocistoson.

These cells inside the blastocistoson pluripotent embryonic stem cells and capable of causing any type of tissue.

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