pt. 3 & Chapter 10 Flashcards
what is the hierarchy of stem cells? (6)
totipotent
pluripotent = 3 germ layers
multipotent
limited differentiation potential
limited division potential
functional non-mitotic neuron
what are the three ways stem cells can proliferate? (don’t describe them, only list)
- single-cell asymmetry
- population asymmetry
- adult stem cell lineage
describe single-cell asymmetry
one of the two daughter cells is less potent than itself (ex: pluripotent) and the other is as potent as itself (ex: totipotent)
describe population asymmetry
- one daughter cell makes all its progeny as potent as itself
- other daughter cell makes all its progeny less potent than itself
describe adult stem cell lineage
- multipotent (form many types)
- committed (1-2 types)
- progenitor (transit amplification)
- differentiated (specific)
what is a progenitor cell?
makes the specific differentiated cell
- constantly being made
how are the differentiated cell types determined when looked at bone marrow stem cells? (list the three main categories)
based on the surface tension (elasticity)
- low = neural
- medium = muscle
- high = bone
elasticity of the cells serves as a marker for cell type
describe collecting stem scells from a morula
hard to do unless grown in vitro
- best for stem cells
- TOTIPOTENT
describe collecting pluripotent cells from a blastocyst
from ICM
- more restricted for cell type it can become
describe collecting pluripotent cells from a fetus
from primordial germ mass
- very restricted
describe collecting pluripotent cells from an adult
not as pluripotent, but can still be induced in culture
how are stem cells induced in culture?
somatic cell nuclear transfer
- take out nucleus & put into enucleated egg, grow in culture
what are the three stem cell signals researchers look for when determining potency?
Oct4, Sox2, Nanog
- Oct4 binds to Sox2, this activates Nanog to turn on embryonic stem cell genes
what did Yamanaka do?
added Oct4 to adult cells to see if they could dedifferentiate
- was able to do it through using different combinations of stem cell signals (all included Oct4, Sox2)
what is a neuroblast?
precursor cell for neural cells
what do the cells become if they have high BMP levels?
skin
what do the cells become if they have medium amounts of BMP?
neural crest cells
- para NS
- symp NS
- glial cells
what do cells become if they have low BMP levels?
neural tube
- brain
- spinal cord
- motor neurons
what direction does the neural tube form during nerulation?
anterior to posterior
what are the four steps of primary neurulation? describe them
ANTERIOR, BRAIN
1. shaping & folding = thickening of layers
2. elevation = edges raise
3. convergence = edges are pushed together
4. closure = neural plate sides fuse, crest cells migrate away
what are the four steps of secondary neurulation? describe them
POSTERIOR, spinal cord
1. condensation = mesodermal cells pack together
2. transition = mesodermal cells change to ectodermal
3. cavitation = cells stick on two sides, creates hollow center
4. coalesce = formation of neural tube (ectodermal cells)
describe the difference between an early gastrula and late gastrula
early = mountain range, hollow valley
late = cells have fused on the sides, hollow hole
describe the cell layers of neural cells
pseudostratified (not separate layers)
describe how researchers know where the cells are in the cell cycle based on location to the lumen
S phase = cells at top (outer) of neural tube
M phase = cells at bottom (lumen) of neural tube
what are the three layers the neural cells divide into (don’t describe them, just list them)
ventricular zone (ependyma)
intermediate zone (gray matter, mantle layer)
marginal zone (white matter)
now describe each of the three layers the neural cells divide into
ependyma = cells near lumen (center), does the most proliferation
mantle layer = contains cell bodies
white matter = axons, makes tracts that go throughout the body
describe the difference between the dorsal and ventral horns
dorsal = signals come in
ventral = signals go out
what is the thing that separates the dorsal and ventral horns?
sulcus limitans
what are purkinje neurons?
secrete Shh
- connect to several cells
- moves body in coordinated way, balance
what are bergamann glial cells?
synaptic plasticity
- build new neuron projections
what does the granular layer do?
secrete BMPs
describe the function of the following….
dendrites
soma
axon hillock
axon terminal (growth cone, microspikes)
dendrites = receive signal
soma = houses DNA
axon hillock = summate signals, decide on AP
axon terminal = where AP is sent to
- growth cone = moves to sense environment to grow
- microspikes = on the growth cone, part that senses
what are the three primary vesicles of the neural tube?
forebrain, midbrain, hindbrain
what are the five secondary vesicles of the neural tube? what primary vesicle do they come from?
telencephalon (forebrain)
diencephalon (forebrain)
mesencephalon (midbrain)
metencephalon (hindbrain)
myencephalon (hindbrain)
describe the gene expression in the neural tube (two competing signals)
BMPs = roof plate
Shh = floor plate, comes from notocord
- form a gradient and work against eachother
