Understanding:
• The capacity of stem cells to divide and differentiate along different pathways is necessary in embryonic
development and also makes stem cells suitable for therapeutic uses
When a cell differentiates and becomes specialised, it loses its capacity to form alternative cell types
Stem cells are unspecialised cells that have two key qualities:
1. Self Renewal – They can continuously divide and replicate
2. Potency – They have the capacity to differentiate into specialised cell types
Types of Stem Cells
There are four main types of stem cells present at various stages of human development:
Totipotent – Can form any cell type, as well as extra-embryonic (placental) tissue (e.g. zygote)
Pluripotent – Can form any cell type (e.g. embryonic stem cells)
Multipotent – Can differentiate into a number of closely related cell types (e.g. haematopoeitic adult stem cells)
Unipotent – Can not differentiate, but are capable of self renewal (e.g. progenitor cells, muscle stem cells)
Uses of Stem Cells
Stem cells are necessary for embryonic development as they are an undifferentiated cell source from which all other cell types may be derived
Cell types that are not capable of self-renewal (e.g. amitotic nerve tissues) are considered to be non-stem cells
As these tissues cannot be regenerated or replaced, stem cells have become a viable therapeutic option when these tissues become damaged