Developmental Biology Exam 2

Relatively undifferentiated cell that when it divides produces:

1. self-renewal

2. A daughter cell that can undergo further differentiation. Thus, a stem cell has the potential to renew itself at each division (so that there is always a supply of stem cells) while also producing a daughter cell capable of responding to its environment by differentiating in a particular manner.

At least one of two daughter cells that retains its undifferentiated character

2 types of cells (the remaining stem cell and the developmentally committed cell) are produced at each division

An alternative (but not mutually exclusive) mode of retaining cell homeostasis

whose progeny include another multipotent stem cell as well as a stem cell that is committed to a particular cell lineage

committed stem cells produce other committed stem cells as well as progenitor cells that are committed to a particular cell fate and that divide to produce many such cells.

are not stem cells, as they can only undergo a few rounds of cell division. In some organs, such as the gut, epidermis, and bone marrow, stem cells regularly divide to replace worn-out cells and repair damaged tissues. In others, such as the prostate and heart, stem cells divide only under special physiological conditions, usually in response to stress or the need to repair the organ

derived from the inner cell mass of mammalian blastocysts or from fetal gamete progenitor cells (germ cells). These cells are capable of producing all the cells of the embryo (i.e., a complete organism).

found in the tissues of organs after the organ has matured. These stem cells, which are usually involved in replacing and repairing tissues of that particular organ, can form only a subset of cell types.

The ability of a particular stem cell to generate numerous different types of differentiated cells

are capable of forming every cell in the embryo and, in addition, the trophoblast cells of the placenta. The only totipotent cells are the zygote and (probably) the first 4–8 blastomeres that form prior to compaction.

have the ability to become all the cell types of the embryo body but CANNOT generate the trophoblast. Usually pluripotent stem cells are derived from the inner cell mass of the mammalian blastocyst. However, undifferentiated germ cells (and germ cell tumors such as teratocarcinomas) can also form pluripotent stem cells.

is a multipotent cell that can form the white blood cell, lymphocyte, and red blood cell lineages.

are found in particular tissues and are involved in regenerating a particular type of cell.

can produce cells of all 3 germ layers (as well as the germ cells)

multipotent and unipotent stem cells are often grouped together as they have the potential to become only a few cell types.

“transit amplifying cells”

are usually more differentiated than stem cells, having become committed to become a particular type of cell.

Both unipotent stem cells and progenitor cells

extension and folding o the neural plate

bending of the neural plate

convergence of the neural folds

closure of the neural tube