PATHOLOGY

Detailed explanation-1: -Answer. Stem cells are the cells that have an ability to become various types of cells. They are present both during embryonic development (embryonic stem cells) and in the adult body (adult stem cells).

Detailed explanation-2: -Totipotent cells can form all the cell types in a body, plus the extraembryonic, or placental, cells. Embryonic cells within the first couple of cell divisions after fertilization are the only cells that are totipotent.

Detailed explanation-3: -A one-cell embryo (zygote) is “totipotent” in both senses; yet, some authors characterize tumors [1, 2] and stem cells [3, 4] as “totipotent, ‘’ based only on the second definition (ie, the ability of these cells to produce a wide range of cell types).

Detailed explanation-4: -Totipotent stem cells. The known and well characterized totipotent stem cells are found only in early embryonic tissues and derive usually from the first few cell divisions after fertilization.

Detailed explanation-5: -Totipotent stem cells are cells that have the capacity to self-renew by dividing and to develop into the three primary germ cell layers of the early embryo and into extra-embryonic tissues such as the placenta.