Stems cells: cells that are capable of either differentiating into specialised cells or producing more stem cells.

Embryonic stem cells:

They are found in blastocysts (very early stage embryos). They can differentiate into all possible types of specialised cell (pluripotent).

Adult stem cells:

They are found in the developing foetus and onwards. They can only differentiate into certain types of specialised cell (multipotent). They are found specifically in:

• Surface of the eye

• Brain

• Skin

• Breasts

• Testicles

• Gut/intestines

• Muscles

• Bone marrow