Ch. 5 pt 1

Question 1

Stem cells are undifferentiated pluripotent/totipotent cells housed in particular “_______” within a body that are able to _______ indefinitely and give rise to more specialized cells

Answer 1

niches
divide

Question 2

Asymmetrical divisions of stem cells produces what 2 cells?

Answer 2

1) another stem cell
2) a more specialized cell

Question 3

_______: can form all cells of the adult and trophoblast cells

Answer 3

totipotent

Question 4

What is an example of a totipotent stem cell?

Answer 4

zygote (zygote through 4-8 cell stage)

Question 5

_______: can form all cells of the adult

Answer 5

pluripotent

Question 6

What is an example of a pluripotent stem cell?

Answer 6

inner cell mass of blastocyst

Question 7

_______: usually adult stem cells with fates restricted to a subset of cells (a COMMITTED cell type)

Answer 7

multipotent

Question 8

What are the 2 examples of multipotent stem cells?

Answer 8

1) hematopoietic stem cells
2) mammary stem cells

Question 9

_______ cells cannot divide indefinitely, limited reproduction before final differentiation

Answer 9

progenitor cells
- sometimes referred to as transit-amplifying cells

Question 10

Where are embryonic stem cells located?

Answer 10

inner cell mass of mammalian embryos

Question 11

Where are adult stem cells found?

Answer 11

stem cell niches

Question 12

_______ stem cells: function to generate only ONE cell type in the organism

Answer 12

unipotent

Question 13

What is an example of a unipotent stem cell?

Answer 13

spermatatonia

Question 14

What are the external regulators of stem cells?

Answer 14

1) physical contact
2) chemical regulation

Question 15

What are the 2 physical contacts for stem cell regulation externally?

Answer 15

1) cell to cell contacts
2) ECM contacts

Question 16

What are the 3 chemical process that externally regulate stem cells?

Answer 16

1) paracrine
2) juxtacrine
3) endocrine

Question 17

What are the 3 internal regulators for stem cells?

Answer 17

1) cytoplasmic determinants
2) transcriptional regulation (TF networks)
3) epigenetic regulation (chromatin state)

Question 18

Inner cell mass cells adhere to the side of the _______ and is capable for forming all cells of the embryo and associated membranes

Answer 18

trophectoderm

Question 19

_______ along with the trophectoderm will generate extraembryonic membranes

Answer 19

primitive endoderm
- forms placenta, chorion, yolk sac

Question 20

_______ forms all the cell types of the embryo proper and finally adult mammal

Answer 20

epiblast
- pluripotent

Question 21

Cultured ICM or epiblast cells are called _______. These retain their potency and can generate all cell types of the body. Divide indefinitely in culture.

Answer 21

embryonic stem cells (ESCs)

Question 22

_____ transcription factors maintain the pluripotency and uncommitted state of the ICM

Answer 22

3
- oct 4, Nanog, Sox2

Question 23

Symmetric division of trophectoderm cells leads to _______, while asymmetric divisions lead to _______

Answer 23

trophectoderm expansion
2 layer (ICM cell created)

Question 24

During asymmetrical division, there is _______ partitioning of cytoplasmic determinants, and _______ localize between ICM and trophectodermal cells

Answer 24

uneven
E-cadherins
- causes differential gene expression

Question 25

_______ are compartments where continually proliferating stem cells are housed

Answer 25

stem cell niches - once they leave, they begin differentiation

Question 26

Stem cell niches provide physical structures, mechanical, hormonal, and chemical signals that regulate stem cell differentiation and proliferation. These niches are also known as _______

Answer 26

micro-regulatory environments - maintenance of these niches is important to health and appearance

Question 27

In drosophila ovarian niche, Germinal stem cells (GSC) divide into what 2 cells?

Answer 27

1) germinal stem cell 2) cystoblast

Question 28

Germinal stem cells maintain contact to Cap cells via _______

Answer 28

E-cadherins

Question 29

Germinal stem cells are maintained by _______ signals that activate _______ signal cascade inside GSC and prevent differentiation

Answer 29

TGF-β BMP

Question 30

_______ prevents diffusion of TGF-β ligands very far, which allows transcription of _______

Answer 30

ECM BAM (bag of marbles)

Question 31

Neural stem cells (NSC's) retain much of the molecular and physical characteristics of their embryonic progenitor cell the _______

Answer 31

radial glial cell - polarized epithelial cells

Question 32

NSC's have only been identified in TWO regions in the adult mammalian brain:

Answer 32

1) subgranular zone (hippocampus) 2) ventricular-subventricular zone (V-SVZ)(lateral ventricles)

Question 33

What is the order of cells for the neural stem cell niche of the V-SVZ?

Answer 33

B1--> B2--> B3 --> C--> A - 3 cell divisions of C before A

Question 34

Fundamental cellular constituents: - Layer of ependymal cells _______ along the ventricular wall - Neural stem cell called the _______ - progenitor (tansit-amplifying) _______ - migrating neuroblast _______

Answer 34

E cells B cells (1,2,3) C cells A cells

Question 35

distinctive _______ structure are retained throughout mammalian life, although the number of pinwheels and neural cells contain decreases with age

Answer 35

Rosette

Question 36

_______: cell surface adhesion molecule that helps maintain architecture and differential state of Rosette

Answer 36

VCAM1

Question 37

The more closely associated B cells are with ependymal cells the more quiescent they are (_______) the more this association loosens, the more active in proliferation they are (_______)

Answer 37

B1 cells (outside) B2 and B3 cells (middle)

Question 38

_______ family transmembrane receptors are cleaved through cell-to-cell interactions

Answer 38

Notch

Question 39

The _______ is cleaved off and functions as part of a transcription factor complex repressing **proneural gene expression**

Answer 39

Notch intracellular domain (NICD) - decreasing levels allows proliferation and maturation

Question 40

_______ signals promotes neurogenesis by upregulating _______ which in turn inhibits Notch signals

Answer 40

EGFR NUMB

Question 41

___1___ generally promotes gliogenesis. In the V-SVZ, the ___1___ inhibitor ___2___ keeps ___1___ levels low.

Answer 41

1) BMP 2) Noggin

Question 42

As developing B cells move away from ependymal cells, they experience increasing levels of _______, which promotes **neurogenesis** with a preference for glial cells

Answer 42

BMP - (less Noggin)

Question 43

_______ is in contact with the niche and can influence NSC behavior through paracrine factors. This allows response to injury, physiologic state, exercise, and circadian rhythms

Answer 43

Cerebral spinal fluid

Question 44

The neurotransmitter _______ secreted by nearby neuronal precursors negatively feeds back on proliferation

Answer 44

GABA

Question 45

Explain the sonic hedgehog gradient in V-SVZ niche

Answer 45

low (basal, endothelial) --> high (apical, ependymal)