What are stem cells? Explain their role in the field of medicine.

Explanation

(i) Stem cells are unifferentiated cells found in most of the mutli cellular animals. Stem cells are capable of self renewal and exhibit .cellular potency..
(ii) In mammals there are two main types of stem cells - embroyonic stem cells ( ES cells) and adult stem cells. They are isolated from cell mass of a blastocyst.
(iii) ES cells are pluripotent and can produce the three primary germ layers ectoderm, mesoderm and endoderm. Embryonic stem cells are multipotent stem cells that can differentiate into a number of types of cells.
(iv) An adult stem cells or somatic stem cell can divide and create another cell similar to it. They are multipotent and can act as a repair system of the body, replenishing adult tissues. The red bone marrow is a rich source of adult stem cells.
Applications :
(i) The most important and potential application of human stem cells is the generation of cells and tissues that could be used for cell based therapies.
(ii) Human stem cells could be used to test new drugs.
(iii) Stem cell banking : (a) Extraction , processing and storage of stem cells, so that they many be used for treatment infuture. Amniotic cell bank is a facility that stores stem cells derived from amniotic fluid for future use (b) Cord Blood banking is extraction of stem cells from umbilical cord during child birth. placenta, amniotic sac are also rich sources of stem cells.