The Idea of Stem Cells

This is a diagram of Pluripotent Stem Cells. 

   Cells develop into many different cell types in our bodies during early life and growth. When a stem cell divides, each new cell has the capability to either remain a stem cell or become another type of cell with a more important function; such as a muscle cell, a red blood cell, or a brain cell. There are two important characteristics that stem cells are distinguished from other cells. The first characteristic is that  they are unspecialized cells that are capable of renewing themselves through cell division, sometimes after long periods of inactivity. Another characteristic is that under certain experimental conditions, the cells can become tissue or organ-specific cells with special functions. Stem cells regularly divide to repair and replace worn out or damaged tissues, in some organs such as the gut and bone marrow. Stem cells only divide under special conditions, in organs such as the pancreas and the heart.


  Scientists have worked with two kinds of stem cells from animals and humans which are embryonic stem cells and non-embryonic somatic stem cells. Scientists discovered ways to derive embryonic stem cells from early mouse embryos in 1981. Then in in 1998,  a method to derive stem cells from human embryos and grew the cells in the laboratory was developed. These cells are called human embryonic stem cells. The embryos used in these studies were created for reproductive purposes through procedures called invitro fertilization. Stem cells are important to living organisms for a lot of reasons. The inner cells give rise to the entire body of the organism in a blastocyst embryo which is a 3- to 5-day-old embryo. It includes many specialized cell types and organs such as the heart, lung, skin, sperm, eggs, and many other tissues. Some tissues that are in adults such as bone marrow and muscle generate replacements for cells that are lost through injury, diseases, and normal wear and tear. Stem Cells offer new ways for treating diseases like heart and diabetes. Scientists use stem cells in labs to test new drugs and to find the reasons that causes birth effects. 


The research about stem cells continue to advance about how an organism develops from a single cell and how healthy cells replace damaged cells in adult organisms. All stem cells have three properties which are how they are unspecialized, capable of renewing and dividing themselves for a long period of time, and how they can give a rise to specialized cell types. Information is difficult for scientists to be able to grow a large number of unspecialized stem cells in the lab for further experimenting. One of the main properties of a stem cell is that it does not have any tissue-specific structures that allow it to perform specialized functions. Stem cells can't carry oxygen molecules through the bloodstream. But, when stem cells give a rise to specialized cells, this process is called differentiation. The cell usually goes through several stages, while differentiating. There are many questions about the process of stem cell differentiation that still remains. 


I understand about the capabilities and the unique features about stem cells. It's interesting about how stem cells develop into many different cell types in our bodies.