quiz #4 - nervous system Flashcards
main function of the nervous system
communication & control
functional unit of the nervous system
neuron
nerve vs tract
nerve: bundle of axons in PNS
tract: bundle of axons in CNS
glial cell responsible for myelination in the CNS
oligodendrocytes
primary function of schwann cells
myelination in the PNS
term used for small gaps between schwann cells in myelinated axons
Nodes of Ranvier
which part of the neuron receives signals from other neurons?
dendrites
which type of neuron carries information from the brain & spinal cord to muscles & glands?
motor neurons
the RMP of a neuron is primarily maintained by…
ion channels
which ion is most involved in generation of an action potential?
Na+
during depolarization of a neuron, which ion moves into the cell?
Na+
period during which a neuron cannot regenerate another action potential
refractory period
action potentials are _____ events
all-or-nothing
process of myelin sheaths speeding up the transmission of electrical signals along axons
saltatory conduction
junction between two neurons or between a neuron & a target cell
synapse
main neurotransmitter involved in the sympathetic nervous system
norepinephrine
what type of neurotransmitter is seratonin?
biogenic amine
what neurotransmitter is primarily inhibitory in the CNS?
GABA, glycine
which type of receptor is activated by Ach in the NMJ?
nicotine receptors
which ion plays a critical role in the release of neurotransmitters from synaptic vesicles?
Ca2+
function of astrocytes
formation of BBB, regulation of neurotransmitter levels, support & nourishment of neurons
part of neuron that conducts impulses away from cell body
axon
where are spinal & cranial nerves found?
PNS
type of neuron that carries impulses toward the CNS
sensory neurons
glial cell responsible for phagocytosis in the CNS
microglia
gray matter of the brain is composed of…
cell bodies of neurons
part of neuron responsible for synthesizing proteins needed for neurotransmitter production
soma (cell body)
in a myelinated axon, the action potential is propagated in a _____ manner, jumping between Nodes of Ranvier
saltatory
function of the sodium-potassium pump
helps maintain RMP by pumping sodium out & potassium in
the all-or-nothing principle means that…
a threshold must be reached for an action potential to occur
primary function of the autonomic nervous system
regulate involuntary functions such as heart rate & digestion
characteristics of an EPSP
depolarizes the postsynaptic membrane
what occurs first in the process of neurotransmission?
action potential reaches axon terminal
function of the BBB
protects brain from bacterial infections
role of neurotransmitters
transmit signals between neurons at synapses
what type of neurons are in the PNS?
sensory & motor
what makes the postsynaptic membrane more negative?
IPSPs (hyperpolarizing)
EPSP (depolarizing)
graded potentials _____ in magnitude with distance from the site of origin
decrease
which ion is responsible for depolarization of the neuron during an action potential?
Na+
what is responsible for reabsorbing neurotransmitters from the synaptic cleft?
presynaptic neuron?
main function of the CNS
integration & processing of sensory input
function of the Node of Ranvier
speed up conduction of electrical impulses via saltatory conduction
which neurotransmitter is associated with the PNS?
acetycholine
glial cells involved in the formation of CSF
ependymal cells
main function of the axon terminal
receive signals from other neurons?
release neurotransmitters in the synapse?*
structure of the neuron responsible for maintaining its metabolic functions
soma (cell body)
ion involved in the repolarization phase of an action potential
K+
what are the components of the trigger zone?
axon Hillock, initial segment
which type of axonal transport is unidirectional?
slow axonal transport
fast = both directions
which type of ion channel responds to action and graded potentials?
voltage gated
what contributes to the resting membrane potential (-70mV)
unequal ion distribution
sodium-potassium pump
anions being stuck in the cell (inability of ions to leave cell)
factors that effect the speed of an action potential
- amount of myelination
- axon diameter
- temperature
continuous conduction takes place along _____ axons
unmyelinated
which type of nerve fibre is the slowest?
C fibers, unmyelinated
A: fastest, myelinated
B: medium, partly myelinated
neurotransmitter removal from the synaptic cleft
Diffusion
Enzymatic Degradation
Uptake by Cells
which type of neurotransmitter receptor uses a separate protein (G protein) for receptor and effector?
metabotropic
ionotropic: part of one protein molecule
neuronal regeneration - 3 things in order to regenerate
- must be in PNS
- intact cell body
- myelinated by functional schwann cell
