Stem Cells-The Miracle Units of Human Body

Human body is the work of wonders. With the routine processes and mechanisms going on in the body, there are also certain backup strategies present that make sure that the body can develop or heal when needed.

One of these various backup plans comprise of naïve precursor living cells that are present throughout the body. These cells are known as stem cells and are capable of dividing multiple times, are unspecialized and have the ability to specialize into various types of body cells. These miracle cells give rise to every cell, tissue, and organ in an embryo. Stem cells, unlike any regular cell, can produce any of the various cells of the human body upon multiplication. These cells also possess the potential to self-renew which is the property of reproducing copies of the self several times.

Definition of a stem cell: A single progenitor cell that can either replicate and self-renew or differentiate into any of the various cell types of the body.

These master cells of the body have repair properties and they can restore tissue physiology by differentiating into other cell types. They also secrete a broad spectrum of biological molecules that help in the restoration of tissue functioning. Stem cells can also differentiate into cell types other than their functional and class domain and this property is known as plasticity. These unique features of the stem cells constitute a repair mechanism by proliferating and replacing other damaged cells thus restoring the tissue physiology. Tissue regeneration mostly involves activation of these pre-existing progenitor cells. These characteristics play important role in the development of the human body and regeneration of injured tissues or organs in the adult body.

Types of Stem Cells

These precursor cells are of several types including;

Embryonic Stem Cells (ESCs) are found in the embryonic body. Subject to when these cells are harvested from the embryos, ESCs can give rise to just about any cell in the human body.

Adult Stem Cells are found in infants, children and adults body. These types of stem cells reside in developed tissues including; heart, liver, bone marrow, brain, and kidney. They usually help in restoring the cell repertoire within their resident tissues or the organs.

Induced Pluripotent Stem Cells (IPSCs) are adult, specialized cells that have been experimentally "reprogrammed" into a stem cell-like state.

The Levels of Potency of Stem Cells

The stem cells possess the property to differentiate into other cell types. This varying potential to generate cells of different types dictates the potency of the stem cells. There are five potency levels for stem cells:

Unipotent are those cells that only produce cells of their own class, but do possess the property of self-renewal required to be branded as a stem cell. These types of cells include muscle stem cells.
Oligopotent are the stem cells that can differentiate into a few types of cells and these include lymphoid or myeloid stem cells.
Multipotent is the ability of the stem cells to specialize into a closely related family of cells. These types of cells include hematopoietic stem cells that produce red and white blood cells or platelets.
Pluripotent is the capacity to differentiate into almost all cell types. Examples of stem cells that possess this level of potency are embryonic stem cells and the cells derived from the three germinal layers.
Totipotent is the ability to generate all possible cell types. The cells which possess this level of potency are the zygote and the first few cells that result from the division of the zygote.

The stem cells make it possible for the body to deal with the basic illnesses and injuries by cell regeneration. These cells compensate for the lost cells during injuries and routine body processes. Therefore, the stem cells act as cell bank for our body and provide repair units at times of need.