A STEM CELL IS A CELL THAT HAS THE CAPABILITY TO DEVELOP INTO ANY OF THE DIFFERENT CELL TYPES THAT MAKE UP THE TISSUES AND ORGANS OF THE BODY. STEM CELLS ARE THE ORIGINAL CELLS FROM WHICH AN ENTIRE ORGANISM DEVELOPS. THEY ARE ALSO FOUND IN ADULT ORGANS. EMBRYONIC STEM CELLS (ESC' S) COME FROM A BLASTOCYST (A VERY YOUNG EMBRYO THAT CONTAINS 200 TO 250 CELLS AND IS SHAPED LIKE A HOLLOW SPHERE). STEMS CELLS ARE THE ACTUAL CELLS INSIDE THE BLASTOCYST THAT WOULD DEVELOP INTO A PERSON OR ANIMAL. ADULT STEM CELLS COME FROM THE UMBILICAL CORD AND PLACENTA, OR FROM: BLOOD, BONE MARROW, SKIN, AND OTHER TISSUES.
MEDICAL RESEARCHERS ARE INTERESTED IN USING STEM CELLS TO REPAIR/ REPLACE DAMAGED BODY TISSUES, BECAUSE STEM CELLS ARE LESS LIKELY THAN OTHER FOREIGN CELLS TO BE REJECTED BY THE IMMUNE SYSTEM WHEN THEY ARE IMPLANTED INTO THE BODY. THEY HAVE BEEN USED EXPERIMENTALLY TO FORM THE HEMATOPOIETIC (BLOOD-MAKING) CELLS OF THE BONE MARROW & HEART, BLOOD VESSEL, MUSCLE, AND INSULIN-PRODUCING TISSUE. …
