| Abstract: |
Stern cell can be defined as cells capable of unlimited self-renewal, -.ll:iJineage differentiation, and in vivo functional reconstitution of a ’pal tissue with flexibility in the timing ofthis differentiation.Stem cells classified into two main types:-embryonic stem cells are found in embryos at a very early stage of development. They have the ability to differentiate into any of the over two hundred types of cells that make up the human body. Adult stem cells have the ability to differentiate into varieties of a particular type of cell, determined by the type of tissue in which they are found. For example, blood stem cells found in the bone marrow give rise to red blood cells, white blood cells, and platelets. Adult stem cells are found in tissues at all but the very earliest stage of human development in fetal tissues, in children, and in adults. Scientists have thus far been able to isolate adult stem cells from tissue in the eye, skeletal muscle, liver, skin, fat, dental pulp, pancreas umbilical cord, and the lining of the gastrointestinal tract.Stem cell plasticity refers to the ability of adult stem cells to acquire DJialure phenotypes that are different from their tissue of origin. Adult IIoDe marrow cells (BMCs) include two populations of bone marrow stem cell (BMCs): hematopoietic stem cells (HSCs), which give rise to all mature lineages of blood, and mesenchymal stem cells (MSCs), which can differentiate into bone, cartilage, and fat.The most widely studied example of adult stem cells is ••• ’upoietic stem cells (HSCs), which sustain formation of the blood une systems throughout life.
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