Basics of Cellular Communication Flashcards
what is the functional unit of the nervous system?
neuron/nerve cell
what does the Na/K pump do?
actively pumps K+ into the cell and removes Na+ from the cell to maintain 3Na+/2K+
what is the range of resting membrane potential?
-30mV to -90mV
what is the action potential generated by?
opening of voltage-gated Na+ channels which occurs at the neurons threshold potential
what is the resting membrane potential restored by after the action potential?
closure of voltage-gated Na+ channels coupled with K+ channels opening
K+ leaves the cell
when do K+ channels close?
approximately the original resting membrane potential
where is the action potential initiated?
axon hillock
unidirectional
how can graded membrane potentials lead to action potential?
spatial summation
temporal summation
what are graded membrane potentials caused by?
synaptic activity: ligand gated ion channels
when do voltage sensitive Ca++ channels open?
when the membrane is depolarized by the action potential
what does intracellular Ca++ lead to?
neurotransmitter release
what must happen for vesicles to release neurotransmitter?
docked near membrane
detect Ca++ levels
fuse with membrane to release contents
what type of proteins are involved in many of the processes at the chemical synapse?
SNARE proteins
what is the major excitatory neurotransmitter in the brain?
glutamate
what is the excitatory neurotransmitter at the neuromuscular junction?
acetylcholine
what is the major inhibitory neurotransmitter in the brain?
GABA
what type of receptors do neurotransmitters act upon?
receptors that are classified as either ligand-gated ionotropic receptors or G-protein coupled metabotropic receptors
how many axons do multipolar neurons have?
one
what do biogenic amines do?
effects depend upon what receptor they activate
where are bipolar neurons found?
special sensory systems: retina, olfactory epithelium, vestibulocochlear nerve
what are unipolar or pseudounipolar neurons like?
two axons rather than dendrites and an axon
what do glia do?
provide mechanical and physical support
provide nutrients (oxygen) to neurons
remove cellular debris
remove toxic/bad substances
electrical insulation
where do the axons of unipolar/pseudounipolar neurons extend?
one from sensory receptors in periphery
one towards spinal cord
what do schwann cells do?
myelinate peripheral axons
provide trophic factors and nutrients
involved in axonal regeneration
what do satellite cells do?
support cells of the peripheral nervous system
what are microglia?
tissue resident macrophages of the CNS
what are microglia responsible for?
immuno-surveillance
immuno-regulation
what do oligodendrocytes do?
myelinate axons within the CNS to regulate the speed of electrical conductance
what cells play a role in the blood brain barrier?
astrocytes
what cells provide the lining of the ventricular cavities in the CNS and central canal of the spinal cord?
ependymal cells
what does the plasma membrane of the neuron determine?
morphology
are there more K or Na diffusion channels in the neuron?
more K leak channels
what is the range of resting membrane potentials?
-30mV to -90mV
what type of ion channels cause graded membrane potentials?
ligand gated
what are neuronal SNARE proteins involved in?
many of the processes for chemical synapse: vesicle release
what do neurotransmitters act on?
receptors: ligand-gated ionotropic receptors or G-protein coupled mechanotropic receptors
what are some multipolar neurons?
alpha motor neurons in spinal cord
pyramidal neurons in cerebral cortex
describe a bipolar neuron
two processes extend from cell body: dendrites and axon
how many primary brain tumors in dogs are gliomas?
35%
where are satellite cells found?
peripheral ganglia
what are microglia responsible for?
immuno-surveillance and immuno-regulation
how many axons can one oligodendrocyte myelinate?
5-6
what maintains structural integrity of the CNS following injury resulting in neuronal cell loss?
astrocytes
what do ependymal cells do?
produce and circulate cerebrospinal fluid
neural stem cells under certain conditions
source of immune regulators
can schwann cells myelinate multiple segments of axons?
no
which support cells play a role in neuropathic pain?
satellite cells
what cells have a critical role in the clearance of excitatory transmitters and ions from the synaptic cleft?
astrocytes
