A stem cell is a cell that can change into another type of cell. Stem cells are responsible for the formation and development of living organisms. They also ensure that certain cells in our body with short life spans can be renewed.
A stem cell is a cell that can change (differentiate) into another type of cell. We distinguish between four types of stem cell. The potential to mature into various types of cell varies with the type of stem cell. The best-known stem cell is the multipotent stem cell.
When a sperm cell fuses with an egg cell, a zygote is formed. A zygote is an example of a totipotent stem cell. A totipotent stem cell can grow into a complete organism (in the right environment). Initially, an embryo consists only of totipotent stem cells. Later, these cells specialize and form cells that each have their own function. These specialized cells can then perform no other functions and can never revert to being stem cells.
Pluripotent stem cells can differentiate into cells from all three of the embryo's germ layers. These stem cells can be obtained from various sources: embryos, fetuses, therapeutic cloning, or by reprogramming differentiated cells into induced Pluripotent stem cells (iPSCs).
Multipotent stem cells are cells that can differentiate into a limited number of cell types. Most multipotent stem cells are adult stem cells (AS). Adult stem cells are undifferentiated or non-specialized cells that can be found in specialized tissue in an organism after birth. They are needed in the body to renew certain cells that have a short life span. An example is hematopoietic stem cells which create red blood cells, white blood cells, and platelets. Hematopoietic stem cells are found in the bone marrow, blood, and umbilical cord blood.
Unipotent stem cells are able to make one particular type of differentiated cell.