Stem Cells, Cell Proliferation, & Differentiation Flashcards
where is the nuclei apparent in adipocytes?
pushed off to the side
define morula
solid ball of cells formed as zygote undergoes cleavage on Day 4
define early blastocyst
hollow balls of cells with a fluid-filled cavity on Day 6
define late blastocyst
pre-embryo with embryonic disk, 2 layers of cells that become the embryo proper on Day 10
define gastrula
embryo with 3 primary germ layers (ectoderm, mesoderm, and endoderm) on Day 16
when does cell movement begin?
during formation of gastrula and primitive streak
describe process of cell differentiation leading to the generation of specialized cell types from stem cells
stem cell –> external signals (growth factors) –> signal transduction (pathways activation) –> transcription factor (activation) –> epigenetic modifications (dna methylation, histone modification) –> gene expression changes –> differentiated cell
True of False: stem cells exist in the embryo and in the adult
True
During embryogenesis, most cells commit to a specific ________ to generate the cell types of the body.
lineage
adult stem cells can be reprogrammed by introducing extra copies of genes that control pluripotency via what medical technology?
Induced pluripotent stem cells (iPS cells)
Changes in gene expression lead to _________ of cells to a specific lineage
commitment
____________________ generates progenitor cells of a particular tissue. These cells are available to repopulate the specific cells of that tissue.
Lineage commitment
what kind of relationship does commitment and proliferative potential have?
an inverse relationship
describe totipotent cells
self-renewing, proliferative, uncommitted
describe pluripotent & multipotent cells
self-renewing, proliferative, minimally committed
describe progenitor cells
self-renewing, proliferative, lineage committed
describe organs
minimally or non-proliferative, differentiated
What are the 2 classes of differentiated cells?
resting/quiescent cells & postmitotic cells
resting/quiescent cells
in G0, mitotically inactive but can resume proliferation.
postmitotic cells
have left the cell cycle and are incapable of cell division
- neurons
- cardiac muscle cells
- mature white blood cells
describe mesenchymal cells
multipotent, non-marrow tissues
bone marrow, testis, intestine, & skin are examples of
minimally committed adult stem cells constitutive
cell division for renewal.
hepatocytes & the hematopoietic system are examples of
renewing cells (hematopoietic)
resting but inducible cells (hepatocytes)
brain and skeletal muscle are examples of
post-mitotic; terminally differentiated cells that do not divide after differentiation
State the Three possible outcomes of stem cell division
1) 2 new stem cells (symmetric)
2) 2 committed cells (symmetric)
3) 1 stem cell + 1 committed cell (asymmetric)
- the differentiated, committed cell is lineage restricting and cannot pass on numb
how are symmetric stem cells divided?
between anterior and posterior (vertical line)
how are asymmetric cells divided?
between basal and apical (horizontal line)
when do extrinsic and intrinsic factors that lead to cell differentiation and specialization appear?
early embryogenesis and persist through life
how many human blood cells are lost every day and are continuously produced from stem cells in the bone marrow?
100-200 billion
where are Hematopoietic (blood-forming) stem cells produced?
in bone marrow
As the intestinal epithelial stem cells constantly renew, how often to we see a turnover of intestinal cells?
every 5-7 days
what are the layers of the epidermis from the bottom up
basement membrane
basal
spinous
granular
cornified
True or False: Different neuronal cell types in each layer come from the same neuroprogenitor population.
True
Mature hepatocytes are fully
differentiated and are in the _______
resting / G0 phase of the cell
cycle.
True or False: If the liver becomes injured & loses cells, hepatocytes can resume the cell cycle and replenish their numbers
True
True or False: Skeletal muscle normally has little cell turnover but can regenerate rapidly in response to injury or exercise.
True
True or False: Satellite cells (stem cells of adult muscle) are normally arrested in G0, but proliferate
in response to injury.
True
Skeletal and cardiac muscle can only be replenished by
satellite cells
define labile
prone to change
- can be used to describe renewing cells
