Stem Cells Flashcards
Cells are considered embryonic stem cells up to the development of the ______
Morula
Morula define:
cluster with no central cavity
Blastula:
- Blastocoel:
Blastula: comes from further division of the morula and the formation of the central cavity. There are now two types of cells
- Blastocoel: the central cavity formed in the blastula
What are the two cell types of the blastula?
Trophoblast cells: form outer layer (can become only placenta cells)
Inner cell mass cells: embryonic stem cells of the blastula (can become any embryonic cell)
TOTIPOTENT:
PLURIPOTENT:
MULTIPOTENT:
UNIPOTENT:
TOTIPOTENT: Can become any cell of the embryonic body or placenta
PLURIPOTENT: can become any cell in the embryonic body
MULTIPOTENT: Can become several closely related cell types
UNIPOTENT: Can only become a single cell type
give an example TOTIPOTENT: PLURIPOTENT: MULTIPOTENT: UNIPOTENT:
TOTIPOTENT: Early or late morula cells
PLURIPOTENT: Inner cell mass cells
MULTIPOTENT: hemopoietic (blood forming) stem cells
UNIPOTENT: muscle stem cells, myoblasts and epidermal stem cells, germline stem cells
Can inner cell mass cells be grown in culture? What are the implications? What potency do these cells have?
Yes
They can be differentiated into any specialized cell type.
They are pluripotent
The inner cell mass given time becomes
inner cell mass + time = embryonic disk
Name the three distinct tissue layers that the embryonic disk differentiates into.
Ectoderm
Mesoderm
Endoderm
Early human embryos resemble other vertebrate animals early embryos this provides evidence for?
The evolutionary relatedness of vertebrates to each other.
Adult stem cells:
Are undifferentiated stem cells, which reside in various tissues and continue to divide at a slow rate for the whole lifetime of the animal.
Self-renewal (of adult stem cells):
Refers to the fact that adult stem cells must maintain their population size and not all differentiate. The rate of self renewal is about 50%
Somatic stem cells are
Adult stem cells
What is the only source of pluripotent adult stem cells?
The umbilical cord
The majority of adult stem cells display what types of potency?
Multipotent ex Mesenchymal stem cells adipose-derived stem cells endothelial stem cells
Bone marrow tramsplants were pioneered by
E donnell Thomas
Stem cell niche:
the microenvironment in which the stem cell lives.
The niche interacts with the stem cell to determine it’s developmental fate
- by preventing or stimulating differentiation and mitosis (each independently)
Specialization of a cell involves what?
Switching off unneeded genes, and turning on needed genes. Therefor making sure the cell in only utilizing energy and space on what it needs for its function.
CHARACTERISTICS of Adult Stem Cells
1.) Exhibit self-renewal by mitotic cell division.
2.) Reside in various tissues alongside differentiated cells.
3.) Continue to divide indefinitely at relatively slow rates.
4.) Rare - only about 1% of bone marrow cells are stem cells.
5.) Plain-looking (nondescript appearance) – difficult to identify.
6.) Retain various levels of potency (developmental potential).
7.) Maintain the normal turnover of cells within tissues.
8.) Act as a repair system – replace damaged cells.
9.) Following tissue damage, the niche signals to adult stem cells to
divide and repair the tissue.
Human tissues that contain adult stem cells:
SKIN HAIR FOLLICLES INTESTINAL EPITHELIUM HEART BRAIN BONE MARROW SKELETAL MUSCLE
Satellite cells are?
The true adult skeletal muscle stem cells
Stem cells of the hair follicle
Reside in the bulge region (midway into root) Migrate down towards the matrix and up towards the sebaceous gland and the epidermis.