STEM CELLS
Properties:
1) Unspecialised (no tissue-specific structures)
2) Capable of dividing and renewing themselves for long periods by mitosis (proliferation)
3) Can differentiate into specialised cells (triggered by both internal and external signals)
● Large nuclear to cytoplasmic ratio
● Able to replenish their own population and generate cells that travel down various
differentiation/developmental pathways
Stem cell potency
● Range of cell types a stem cell can give rise to
● Determined by number of possible developmental pathways through process of
specialisation/differentiation (differential potential of stem cell)
Totipotent Pluripotent Multipotent
Descend from totipotent stem cells Descend from pluripotent stem
cells
Able to give rise to all cell types that Able to give rise to cell types that Able to differentiate into a limited
make up an organism develop from the three germ layers number of cell types
● Any cell type in adult body (endoderm, mesoderm, ectoderm)
● Any cell of extra-embryonic ● Unable to become
membranes (e.g. placenta) differentiated cells that form
extra-embryonic
membranes (e.g. placenta)
Fertilised egg (zygote); first few cells Inner cell mass of blastocyst Adult stem cells (e.g.
produced when zygote divides (embryonic stem cells); fetal tissue hematopoietic/blood stem cells)
rapidly by mitosis to form a morula destined to be part of gonads
Increasing levels of commitment/differentiation/specialisation
Unipotent
Able to differentiate along only one cell lineage (adult stem cells; self-renewal of tissue)
Committed stem cells
● Multipotent and unipotent stem cells
● More limited pathway of development compared to pluripotent cells and are destined to
produce a specific group of cells
● Can give rise to more specifically committed stem cells or generate progenitor/precursor
cells
Copyright © 2019 tonyndr
Properties:
1) Unspecialised (no tissue-specific structures)
2) Capable of dividing and renewing themselves for long periods by mitosis (proliferation)
3) Can differentiate into specialised cells (triggered by both internal and external signals)
● Large nuclear to cytoplasmic ratio
● Able to replenish their own population and generate cells that travel down various
differentiation/developmental pathways
Stem cell potency
● Range of cell types a stem cell can give rise to
● Determined by number of possible developmental pathways through process of
specialisation/differentiation (differential potential of stem cell)
Totipotent Pluripotent Multipotent
Descend from totipotent stem cells Descend from pluripotent stem
cells
Able to give rise to all cell types that Able to give rise to cell types that Able to differentiate into a limited
make up an organism develop from the three germ layers number of cell types
● Any cell type in adult body (endoderm, mesoderm, ectoderm)
● Any cell of extra-embryonic ● Unable to become
membranes (e.g. placenta) differentiated cells that form
extra-embryonic
membranes (e.g. placenta)
Fertilised egg (zygote); first few cells Inner cell mass of blastocyst Adult stem cells (e.g.
produced when zygote divides (embryonic stem cells); fetal tissue hematopoietic/blood stem cells)
rapidly by mitosis to form a morula destined to be part of gonads
Increasing levels of commitment/differentiation/specialisation
Unipotent
Able to differentiate along only one cell lineage (adult stem cells; self-renewal of tissue)
Committed stem cells
● Multipotent and unipotent stem cells
● More limited pathway of development compared to pluripotent cells and are destined to
produce a specific group of cells
● Can give rise to more specifically committed stem cells or generate progenitor/precursor
cells
Copyright © 2019 tonyndr
