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Stem cells differ from other kinds of cells in the body. All stem cells-regardless of their source-have three general properties: they are capable of dividing and renewing themselves for long periods; they are unspecialized; and they can give rise to specialized cell types.

Stem cells are capable of dividing and renewing themselves for long periods. Unlike muscle cells, blood cells, or nerve cells-which do not normally replicate themselves-stem cells may replicate many times, or proliferate. 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.

Scientists are trying to understand two fundamental properties of stem cells that relate to their long-term self-renewal:

  1. why can embryonic stem cells proliferate for a year or more in the laboratory without differentiating, but most non-embryonic stem cells cannot; and
  2. what are the factors in living organisms that normally regulate stem cell proliferation and self-renewal?

Discovering the answers to these questions may make it possible to understand how cell proliferation is regulated during normal embryonic development or during the abnormal cell divisionthat leads to cancer. Such information would also enable scientists to grow embryonic and non-embryonic stem cells more efficiently in the laboratory.

The specific factors and conditions that allow stem cells to remain unspecialized are of great interest to scientists. It has taken scientists many years of trial and error to learn to derive and maintain stem cells in the laboratory without them spontaneously differentiating into specific cell types. For example, it took two decades to learn how to grow human embryonic stem cells in the laboratory following the development of conditions for growing mouse stem cells. Therefore, understanding the signals in a mature organism that cause a stem cell population to proliferate and remain unspecialized until the cells are needed. Such information is critical for scientists to be able to grow large numbers of unspecialized stem cells in the laboratory for further experimentation.

Stem cells are unspecialized. One of the fundamental properties of a stem cell is that it does 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, including heart muscle cells, blood cells, or nerve cells.

Stem cells can give rise to specialized cells. When unspecialized stem cells give rise to specialized cells, the process is called differentiation. While differentiating, the cell usually goes through several stages, becoming more specialized at each step. Scientists are just beginning to understand the signals inside and outside cells that trigger each stem of the differentiation process. The internal signalsare controlled by a cell's genes, which are 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, and certain molecules in the microenvironment. The interaction of signals during differentiation causes the cell's DNA to acquire epigeneticmarks that restrict DNA expression in the cell and can be passed on through cell division.

Many questions about stem cell differentiation remain. For example, are the internal and external signals for cell differentiation similar for all kinds of stem cells? Can specific sets of signals be identified that promote differentiation into specific cell types? Addressing these questions may lead scientists to find new ways to control stem cell differentiation in the laboratory, thereby growing cells or tissues that can be used for specific purposes such as cell-based therapies or drug screening.

Adult stem cells typically generate the cell types of the tissue in which they reside. For example, a blood-forming adult stem cell in the bone marrow normally gives rise to the many types of blood cells. It is generally accepted that a blood-forming cell in the bone marrow-which is called a hematopoietic stem cell-cannot give rise to the cells of a very different tissue, such as nerve cells in the brain. Experiments over the last several years have purported to show that stem cells from one tissue may give rise to cell types of a completely different tissue. This remains an area of great debate within the research community. This controversy demonstrates the challenges of studying adult stem cells and suggests that additional research using adult stem cells is necessary to understand their full potential as future therapies.

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Related Questions

What property is unique to stem cells?

They can develop into every type of cell.


What are cell called before they specialize?

Before cells specialize, they are called stem cells. Stem cells have the unique ability to develop into different types of cells within the body.


What are the steam cells?

Stem cells are undifferentiated cells capable of developing into various cell types in the body. They have the unique ability to self-renew and can divide to produce more stem cells or differentiate into specialized cells, such as muscle, nerve, or blood cells. Stem cells are classified into two main types: embryonic stem cells, which can give rise to any cell type, and adult (or somatic) stem cells, which are more limited in their differentiation potential. Their unique properties make stem cells a key focus in regenerative medicine and research.


How do stem cells differ from other cells?

Stem cells are unique because they have the ability to develop into different types of cells in the body, while other cells have specific functions and cannot change into different cell types.


How do stem cells differ from regular cells?

Stem cells are unique because they have the ability to develop into different types of cells in the body, while regular cells have specific functions and cannot change into other cell types.


Does a stem cell have a function?

stem cells can turn into any cell of the body and preform their function.


What are the types of stem cells?

There are five basic stem cells classifications there is embryonic stem cells, fetal stem cells. There are the Umbilical cord stem cells, placenta stem cells, and lastly there are adult stem cells.


Are Adult stem cells as useful as Embrionic stem cells?

Yes and No. The only big difference is the procedures used in harvesting adult stem cells is considered legal and safe. There's no need to kill a human embryo. Adult stem cells can be harvested from cord blood or human bone marrow. But embryonic stem cells are able to make more kinds of cells than adult stem cells.


How are stem cells unique?

Stem cells are cells that have not yet specialized to become specific parts of the body, like a blood cell, skin cell of a fingertip, or a retina cell in the back of the eye. The cells in animals at some point in time originated from stem cells, beginning with a single cell (the zygote in animals that reproduce sexually).


How are stem cells different from other cells?

Stem cells are capable of self-renewal and assymetrical division to give rise to progenitor cells. Progenitor cells are cells that can further differentiate into other cells though it has lost the stem cell's ability to self-renew. When a stem cell divides, the same stem cell and a progenitor cell is produced. The production of the same stem cell is evidence of self-renewal and the production of a cell different from the parent cell is evidence of assymetrical division (regular mitosis gives rise to two identical daughter cells).


How many different types of tissue stem cells are there?

There are three different types of tissue stem cells in the body. They include the tissue stem cells also known as adult stem cells, embryonic stem cells, and induced pluripotent stem cells.


What kind of stem cells can only develope into cells that are closely related to the original stem cells?

Multipotent stem cells