Ch 13 Lec 2 - Nervous System Flashcards
these are like astrocytes but smaller
oligodendrocytes
oligodendrocytes form blank in the central nervous system
myelin
smallest and least common neuroglial cell
microglia
microglia are derived from blank cells
myeloid
microglia are the blank cells of the nervous system
white blood
main function of microglia
phagocytosis
columnar/cuboidal and have microvilli on luminal surface are are a neuroglial
ependymal
ependymal cells are joined by blank junctions
gap
main function of ependymal cells is to help produce blank
cerebrospinal fluid
associated with soma and assist with exchange of nutrients and is a neuroglial cell
satellite
satellite cells blank neuron from extraneous stimuli
Isolates
neuroglial cells that produce myelin in the peripheral nervous system
schwann cells
schwann cells encloses blank of longer peripheral nerves
axons
main function of schwann cells is to blank large PNS axons
myelinate
blank axons appear gray and many axons associate with a single schwann cell
unmyelinated
unmyelinated cells are found in the blank and are not blank cells
CNS, glial
axons that appear white
myelinated
in the central nervous system, blank myelinate part of several axons
oligodendrocytes
in the PNS, blank cells myelinated part of one axon
schwann
plasma membrane of schwann cell wrapped around axon
myelin
part of schwann cell that contains cytoplasm
neurilemma
gaps in myelin sheath
nodes of ranvier
myelination process starts when you are blank and then stop around age blank
young, 3
myelin functions to blank axons and increase blank
isolate, rate of action potential
the peripheral nervous system can blank a fraction of the axons
regenerate
the regeneration of Schwann cells in PNS
Wallerian process
if the injury separates axon from cell body, the blank portion of the axon will blank along with with myelin sheath
distal, deteriorate
during the regeneration of nerve fibers, blank clean up, some blank cells remain, and a thin blank membrane and later of blank tissue around schwann cells
macrophages, schwann, basement, connective
new axon grows blank to blank millimeters per day when regenerating nerve fibers
3-4
repair in central nervous system is more blank
limited
oligodendrocytes do not blank and repair the central nervous sytem
proliferate
blank produce scar tissue and chemicals blocking regrowth in central nervous system
astrocytes
ability to respond to stimuli
irritability
ability to transmit an impulse
excitability
an electrical impulse changing the permeability of a membrane
action potential
action potential moving down an axon
nerve impulse
impulse travels faster when the axon is blank and has a blank diamater
myelinated, larger
this functions as a control/transmission point and a site of communication
synapse
synapse is a site communication between any two cells with a blank
gap
two types of synapses
electrical, chemical
example of electrical synapse
intercalated discs of cardiac muscle
example of a chemical synapse
neuro-muscular junction
in chemical synapses, blank house neurotransmitters
synaptic vesicle
chemical synapses only exist in the blank
presynaptic cell
chemical synapses release neurotransmitters into the blank
synaptic cleft
receptors on blank membranes register the neurotransmitter in chemical synapses
post-synaptic
chemical synapses proliferates the blank from one cell to the next
action potential
in step 1 at a chemical synapse the action potential reaches the blank of the presynaptic neuron
synaptic knob
receive impulses from afferent fibers and the impulses are carried away on efferent fibers in these
neuronal pools
blank fibers can branch many times before entering a pool
afferent
one neuron to another in series in this pool
serial processing
pool when impulse leaves a pool, it may spread into several output fibers and allows impulse to be amplified
divergence
neuronal pool where a single nerve in pool may receive impulses from 2 or more incoming fibers
convergence
if an impulse leads to the same nerve, they are said to blank
converge
convergence allows summation of impulses from blank
different sources
processing information from several neurons at once
parallel processing
positive feedback continues activity of circuit in this pool
reverberation
one neuron may receive either blank and blank stimuli from multiple neurons
excitatory, inhibitory
the net effect of all input to a cell is called the blank
net charge
if the charge is positive enough to a nerve then it will result in a blank
active potential
the point where an action potential can be produced is known as blank
threshold
inhibitory stimuli bring signals blank threshold
away from
excitatory stimuli bring signals blank threshold
to
in step 2 at a chemical synapse the blank is release
neurotransmitter
in step 3 at a chemical synapse the blank binds to receptors and blanks the postsynaptic membrane
ach, depolarizes
in step 4 at a chemical synapse blank is removed by blank
ach, ache
