11 JUNE 2019 Flashcards
what are two important things astrocytes release?
CA2+ and glutamate
when astrocytes release CA why is that important?
CA helps remodel the cell
when astrocytes release glutamate why is that important?
for action potentials
LTD stands for
long term depression
what does LTD
turns DOWN the signal (like down regulating)
how does LTD happen
we take membrane receptors out of the membrane - inhibit a signal and make it harder to make an AP because neurotrans can’t bind to anything
def of LTP short:
silent synapses to active synapses
def of LTD short:
active synapses to silent synapses
what happens when a cell dies?
glutamate is released (leaks out of cell - squished cell) and flows to other cells, but too much can make it toxic and kill other cells (like a poison released from first dead cell)
how does glutamate kill a cell though?
glutamate open NMDA channels which releases to much CA - instead of promoting LTP too much CA comes in and kills the cells
there are four types of excitotoxicity what are they? aka what four ways can CA KILL a cell?
- glycolysis
- protease
- protein enzymes
- solute
why is glycolysis bad
glycolysis can lead to a lactic acid which lowers pH which then kills cell
glycolysis > lactic acid > low pH
how can protease be bad for a cell?
protease is an enzyme that eats other proteins, eats away its own cell membrane
protease > degrades cell proteins
how can protein enzymes be bad for a cell?
protein enzymes will turn on inappropriately, create oxygen free radicals which are always poison
protein enzymes > oxygen free radicals
how is solute bad for the cell?
CA bring in water with it, causing the cell to swell up and then pop
solute > swell up
what 3 things happen when a axon gets injured:
- distal end will degenerate
- myelin shealth will degenerate
- muscle will atrophy
wallerian degeneration def:
the distal degeneration of axon and myelin distal to the point of injury
is all lost for the proximal axon when it gets injured?
NO proximal end has potential to REGROW
what is collateral sprouting:
when an axon dies a second axon sprouts (grow another trunk) to supply thatinnervation
what is regenerative sprouting:
an axon can simply regenerate/regrow itself all the way back out
what is the rate of neuron regrowth
an inch a month
what is the first response after injury?
the recovery of synaptic effectiveness
how does recovery of synaptic effectiveness start:
it relieves pressure from swelling - reduces swelling off of axon
what is the second modaluation after an axon injury:
denervation hypersensitivity:
what are the steps of denervation hypersensitivity:
- a neuron dies cutting off connection to 2nd neuron
- 2nd neuron externalizes soo many extra receptors trying to pick up input from missing cell
- that makes it SUPER sensitive since external environmental stimulus can over load it now
what are the three mechanisms after axon injury:
- recovery of synaptic effectiveness
- denervation hypersensitivity
- synaptic hypereffectiveness
- unmasking of silent synapses
what does 4. unmasking of silent synapses do?
uses LTP to wake up silent synapses so that more APs can be made
real quick what are the steps of LTP
increase glutamate to increase CA to bring AMPA receptors to the membrane AMPA takes in more neurotransmitters = more APs
what does the precentral gyrus do?
voluntary motor control
what is the take home message of the monkey experiment?
PRACTICE
PRACTICE
PRACTICE
what are two interventions that can be supported from monkey experiment?
body weight support treadmill training
CIMT
what are four things to know about reorganization of the cerebral cortex:
- practice practice practice
- activities should be fx
- fx activities should start early
- but not too early
when is the pre-embryonic stage?
conception to 2 weeks
when is the fetal stage:
after 8 weeks till the rest of the time
what plate is dorsal?
the association plate
what does the association plate hold?
cells of the sensory systems but NOT the peripheral sensory system
where is the peripheral sensory system held?
the dorsal root ganglion
what is the ventral plate?
the motor plate
what does the motor plate hold?
the peripheral motor systems / cells
what are the three layers in a somite?
sclerotome
myotome
dermatome
what do sclerotomes hold?
bone hardening stuff
what do myotomes hold?
cells of the muscle system
what do dermatomes hold?
cells for the skin
columns are
white matter
horns are
grey matter
what is the grey inner layer called?
the mantle layer
what does the mantles layer hold?
cell bodies of neurons :grey motor : multipolor neurons
what is the outer whiter layer called?
marginal layer
what doe the marginal layer hold?
cells of the myelin shealth so poligodendrites/ schwann cels
what is the marginal layers job?
to protect cells because it holds myelin shealth
what are the top and bottom closed holes of the neural tube called ?
the superior and inferior neuropores
what do the neuropores do?
they close up the neural tube at the top and bottom of the spinal cord
what happens to the head in the fetal stage?
it SWELLS - also has it cells migrate down to form the spinal cord and swells outward but the head get BIG
what is a good anology of the developing spinal cord of the fetus aka BABY :
A CANNOLI SILLY!!
what are the three layers of the neural tube?
- ectoderm
- mesoderm
- endoderm
what does the mesoderm become?
the mesoderms swells up into 31 pairs of balloons and holds the somite with its three layers
what does the ectoderm hold?
sensory organ info, sensory receptors of cells of nervous systems
what is the purples part of the neural tube diagram?
the nervous system
what days does the neural tube form?
18-26
what does the mesoderm hold?
dermis, muscles, skeleton circulatory system
what does the endoderm hold?
gut, liver, pancreas, respiratory systems
what do the light purple cells turn into?
since they migrate to the back
they turn into motor cells
which are multi polar
what do the dark purple cells turn into?
somatosenosry cells = sensory
= pseudounipolar
what part of the diagram is the neural crest:
the dark purple
what is dark purple part?
the neural crest = which turns into two clusters
what is the light purple part?
the nervous system
