Stem Cells, Cell Proliferation, & Differentiation

Question 1

where is the nuclei apparent in adipocytes?

Answer 1

pushed off to the side

Question 2

define morula

Answer 2

solid ball of cells formed as zygote undergoes cleavage on Day 4

Question 3

define early blastocyst

Answer 3

hollow balls of cells with a fluid-filled cavity on Day 6

Question 4

define late blastocyst

Answer 4

pre-embryo with embryonic disk, 2 layers of cells that become the embryo proper on Day 10

Question 5

define gastrula

Answer 5

embryo with 3 primary germ layers (ectoderm, mesoderm, and endoderm) on Day 16

Question 6

when does cell movement begin?

Answer 6

during formation of gastrula and primitive streak

Question 7

describe process of cell differentiation leading to the generation of specialized cell types from stem cells

Answer 7

stem cell –> external signals (growth factors) –> signal transduction (pathways activation) –> transcription factor (activation) –> epigenetic modifications (dna methylation, histone modification) –> gene expression changes –> differentiated cell

Question 8

True of False: stem cells exist in the embryo and in the adult

Answer 8

True

Question 9

During embryogenesis, most cells commit to a specific ________ to generate the cell types of the body.

Answer 9

lineage

Question 10

adult stem cells can be reprogrammed by introducing extra copies of genes that control pluripotency via what medical technology?

Answer 10

Induced pluripotent stem cells (iPS cells)

Question 11

Changes in gene expression lead to _________ of cells to a specific lineage

Answer 11

commitment

Question 12

____________________ generates progenitor cells of a particular tissue. These cells are available to repopulate the specific cells of that tissue.

Answer 12

Lineage commitment

Question 13

what kind of relationship does commitment and proliferative potential have?

Answer 13

an inverse relationship

Question 14

describe totipotent cells

Answer 14

self-renewing, proliferative, uncommitted

Question 15

describe pluripotent & multipotent cells

Answer 15

self-renewing, proliferative, minimally committed

Question 16

describe progenitor cells

Answer 16

self-renewing, proliferative, lineage committed

Question 17

describe organs

Answer 17

minimally or non-proliferative, differentiated

Question 18

What are the 2 classes of differentiated cells?

Answer 18

resting/quiescent cells & postmitotic cells

Question 19

resting/quiescent cells

Answer 19

in G0, mitotically inactive but can resume proliferation.

Question 20

postmitotic cells

Answer 20

have left the cell cycle and are incapable of cell division
- neurons
- cardiac muscle cells
- mature white blood cells

Question 21

describe mesenchymal cells

Answer 21

multipotent, non-marrow tissues

Question 22

bone marrow, testis, intestine, & skin are examples of

Answer 22

minimally committed adult stem cells constitutive
cell division for renewal.

Question 23

hepatocytes & the hematopoietic system are examples of

Answer 23

renewing cells (hematopoietic)
resting but inducible cells (hepatocytes)

Question 24

brain and skeletal muscle are examples of

Answer 24

post-mitotic; terminally differentiated cells that do not divide after differentiation

Question 25

State the Three possible outcomes of stem cell division

Answer 25

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

Question 26

how are symmetric stem cells divided?

Answer 26

between anterior and posterior (vertical line)

Question 27

how are asymmetric cells divided?

Answer 27

between basal and apical (horizontal line)

Question 28

when do extrinsic and intrinsic factors that lead to cell differentiation and specialization appear?

Answer 28

early embryogenesis and persist through life

Question 29

how many human blood cells are lost every day and are continuously produced from stem cells in the bone marrow?

Answer 29

100-200 billion

Question 30

where are Hematopoietic (blood-forming) stem cells produced?

Answer 30

in bone marrow

Question 31

As the intestinal epithelial stem cells constantly renew, how often to we see a turnover of intestinal cells?

Answer 31

every 5-7 days

Question 32

what are the layers of the epidermis from the bottom up

Answer 32

basement membrane
basal
spinous
granular
cornified

Question 33

True or False: Different neuronal cell types in each layer come from the same neuroprogenitor population.

Answer 33

True

Question 34

Mature hepatocytes are fully
differentiated and are in the _______

Answer 34

resting / G0 phase of the cell
cycle.

Question 35

True or False: If the liver becomes injured & loses cells, hepatocytes can resume the cell cycle and replenish their numbers

Answer 35

True

Question 36

True or False: Skeletal muscle normally has little cell turnover but can regenerate rapidly in response to injury or exercise.

Answer 36

True

Question 37

True or False: Satellite cells (stem cells of adult muscle) are normally arrested in G0, but proliferate
in response to injury.

Answer 37

True

Question 38

Skeletal and cardiac muscle can only be replenished by

Answer 38

satellite cells

Question 39

define labile

Answer 39

prone to change

• can be used to describe renewing cells