A&P 3 Flashcards
(184 cards)
Neurotransmitters stay in the synapse for only a very short time, leading to a transient response
in the post-synaptic cell
O
True
EPSPs are most commonly stimulated by the opening of a
O
non-specific cation channel
Most metabotropic neurotransmitter receptors are
O
G protein-coupled receptors
Opening a chloride channel in a cell that does not regulate chloride will
O
cause a resting neuron to stay at the same membrane potential
dampen an EPSP
dampen an IPSP
Define convergence in relation to the nervous system.
O
multiple neurons synapse onto a smaller number neurons
Define divergence in relation to the nervous system.
O
small number neurons synapse onto a larger number neurons
Define saltatory conduction
O
action potentials jump from node to node of Ranvier down length of axon
Describe spatial summation in the nervous system
when you set more than one postsynaptic potential from multiple synapses happening at the same time in a postsynaptic neuron so that the effects of all synapses add together to influence the membrane potential
Describe temporal summation in the nervous system
when you get one presynaptic neuron firing and releasing neurotransmitters more than once in a short period of time, so the effects on the membrane potential in post-synaptic cell from all the bouts of NT release adds together
Describe two ways of decreasing calcium entry in a presynaptic terminal to decrease
neurotransmitter release
O
axo-axonic synapse- activation of receptores on terminal by NT
autoreceptors- activated on presynaptic terminals by NT released by that neuron
These both lead to hyperpolarization of terminal
Then when the action potential reaches the terminal, it won’t depolarize as much leading to fewer voltage-gated Ca2+ channels opening thus less Ca2+ entering the cell and less NT release.
What are the four ways that neurotransmitter concentrations decrease in the synapse soon
after release?
O
reuptake into presynaptic cells terminals or uptake by glial cells (astrocytes)
diffusion out of synapse
enzymatic degradation in the synapse
receptor-mediated endocytosis in postsynaptic cell
What are the two general types of synapses and which is most common?
O
chemical: excitatory and inhibitory (common)
electrical
What are two ways of increasing the rate of propagation of an action potential? Which of these
is most effective?
O
myelination of the axon (effective)
increase axon diameter
What does EPSP stand for in neuroscience?
O
excitatory post-synaptic potential
What does IPSP stand for in neuroscience?
O
inhibitory post-synaptic potential
Draw a flow chart for the steps of neurotransmitter release starting with the action potential
reaching the axon terminal.
O
action potential reaches axon terminal
conf change in voltage-gated Ca2+ channel (VGCC)
VGCC opens
Ca2+ enters cytosol
Ca2+ binds to synaptotagmin
conf change in synaptotagmin
synaptotagmin binds to SNARE proteins
SNARE proteins pull vesicle into contact w/ the plasma membrane
vesicle membrane and plasma membrane fuse
exocytosis of NT
The thicker the axon diameter
O
the slower potassium leaks out of the cell during an action potential
Opening a chloride channel in a cell that does not regulate chloride would
O
dampen the depolarizing effect of opening a sodium channel
The highest concentration of voltage-gated sodium channels is in the plasma membrane of
O
the nodes of Ranvier of mylinated neurons
Action potentials during the relative refractory period
have a lower amplitude than action potentials fired from the resting membrane potential
What protein does calcium bind to in the presynaptic terminal that leads to exocytosis of neurotransmitter?
synaptotagmin
EPSPs and IPSPs are graded potentials.
O
True
Receptor number in the post-synaptic density is variable.
True
Internodal regions of a myelinated neuron are
less leaky for potassium