Specialisation
In multicellular organisms cells become specialised to carry out different functions. This allows the organisms to function more efficiently.
Stem cells in animals
All of the specialised cells in an animal develop from A cell found in foetuses, embryos and some adult tissues that can give rise to a wide range of other cells..
An early animal An organism in the early stages of development. contains stem cells that have the potential to divide and develop into any type of specialised body cell.
As the embryo grows and develops, its stem cells divide to produce cells that develop into the different types of specialised cell it will need to make functioning tissues and organs.
Some locations in the adult body, such as the lower layers of the skin and small intestine, still contain populations of stem cells. These cells can divide to produce a limited range of specialised cell types to replace cells that have been damaged.
Most specialised cells lose the ability to divide, so if they die and there are no stem cells present to produce cells to replace them, then part of a tissue or an organ may be permanently lost.
Stem cells produced in cell culture have the potential to be used to replace specialised cells in a person affected by disease or injury.