Bio- Stem Cells

Stem cells are unspecialised cells, capable of dividing into many different types of cells.

An embryo develops from a fertilised egg. Cells in the early stages of the development of an embryo are called Embryonic stem cells. They are cells that have not yet been specialised and so, are undifferentiated. Some stem cells remain in the bodies of adults as adult stem cells.

When embryonic cells divide, they stop being the same and they stop getting smaller with each division. Instead, they start to differentiate into different types of cells. At this point, stem cells no longer form 2 new stem cells when dividing but instead, one of 2 daughter cells becomes a progeny/tissue cell. These cells continue dividing + differentiating- each time becoming more and more specialised. Some will become nerve cells, others will become blood cells, bone cell, etc etc.

Stem cells found in Bone marrow have been used for many years, to treat diseases that affect blood cells, such as Leukaemia- by a Bone Marrow Transplant. -Bone marrow is harvested from a suitable donor under general anaesthetic. -The patient’s abnormal cells are destroyed by Chemotherapy, and/or Radiotherapy. -The donated bone marrow is injected into the patient -Stem cells in the injected bone marrow circulate in the blood + end up in the patient’s bone marrow, where they start to divide + produce new blood cells.

-They are painless in use -They are Very powerful cs -They can turn into any type of cell -They may be cells left over from IVF, which would’ve otherwise been thrown away -Faster cell division

-They are relatively new in the medical world- untested so less reliable, so may be rejection -Ethical issues, as the embryo cannot agree and -The embryos may be harmed or die -May be cancerous - as they can differentiate into any type and the cell division might become uncontrollable

-Doctors have more experience with these trials -Less likely to become cancerous -Come from volunteers so more ethically acceptable -Patient’s own stem cells could be used to treat their own disease, so no immune rejection. -Reduce the need for Organ transplants- which have long waiting lists

-Limited cell type so can only treat some diseases -Risk of infection as extracted from human -Process is painful