Cell specialisation - stem cells Flashcards
What is a stem cell?
A stem cell is a cell that can divide (by mitosis) an unlimited number of times.
What happens when a stem cell divides?
Each new cell has the potential to remain a stem cell or to develop into a specialised cell through differentiation.
What is a stem cell niche?
A stem cell niche is a specific location in the human body where some stem cells remain after differentiation.
What is the significance of the presence of stem cells in niches?
Their presence gives the capacity for these tissues to regenerate and repair.
What role does bone marrow play in stem cell niches?
Bone marrow provides a niche for stem cells used to replace red blood cells, white blood cells, and platelets.
What is the function of stem cells in hair follicles?
Stem cells in hair follicles promote continual hair growth.
What are the two abilities that the environment of a stem cell niche must have?
- The ability to maintain an inactive state of the stem cells
- The ability to stimulate stem cell proliferation and differentiation.
What is meant by stem cell potency?
Potency is the ability of stem cells to differentiate into more specialised cell types.
What is totipotency?
Totipotent stem cells can differentiate into any cell type found in an embryo, as well as extra-embryonic cells.
Which cells are considered totipotent?
- The zygote formed after fertilisation
- Embryonic cells up to the 16-cell stage of human embryo development.
What is pluripotency?
Pluripotent stem cells can differentiate into any cell type found in an embryo but cannot differentiate into extra-embryonic cells.
What is multipotency?
Multipotent stem cells can differentiate into closely related cell types.
Give an example of multipotent stem cells.
Bone marrow stem cells differentiate into different blood cells.
What is unipotency?
Unipotent stem cells are adult cells that can only differentiate into their own lineage.
Provide an example of unipotent stem cells.
Heart muscle cells (cardiomyocytes) can generate new cardiomyocytes.
True or False: Most cells in animal bodies are unipotent.
True.
