Friday, June 19, 2009

Stem Cells - Part 1 => Emerging as a Miracle to Mankind !!!

What are Stem Cells:-

Stem Cells have the remarkable potential to develop into many different cell types in the body during early life and growth. In addition, in many tissues they serve as a sort of internal repair system, dividing essentially without limit to replenish other cells as long as the person or animal is still alive. When a stem cell divides, each new cell has the potential either to remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell.

Specific Characteristics of Stem Cells:-

1. They are capable of renewing themselves through cell division, sometimes after long periods of inactivity.

Ø Unlike muscle cells, blood cells, or nerve cells—which do not normally replicate themselves—stem cells may replicate many times. A starting population of stem cells that proliferates for many months in the laboratory can yield millions of cells. If the resulting cells continue to be unspecialized, like the parent stem cells, the cells are said to be capable of long-term self-renewal.

2. They are unspecialized cells.

Ø They do not have any tissue-specific structures that allow it to perform specialized functions. For example, a stem cell cannot work with its neighbors to pump blood through the body (like a heart muscle cell), and it cannot carry oxygen molecules through the bloodstream (like a red blood cell). However, unspecialized stem cells can give rise to specialized cells.

3. They can be induced to become tissue- or organ-specific cells with special functions, under certain physiologic or experimental conditions, known as differentiation.

Ø Here, the cell usually goes through several stages triggered by the external and internal signals from the cells, becoming more specialized at each step. The internal signals are controlled by a cell's genres, interspersed across long strands of DNA, and carry coded instructions for all cellular structures and functions. The external signals for cell differentiation include chemicals secreted by other cells, physical contact with neighboring cells, etc.

to be continued.. friends!

No comments: