MQ Neurobiology 4 Transmission Flashcards
Place in chronological order the steps describing activation.
a.
K+ ions rush out of the first segment of the axon, rapidly repolarizing that area.
b.
The activation threshold is reached close enough to v-g-Na-ch.
c.
V-g-Na-ch open fully.
d.
Na+ ions rush into of the first segment of the axon, rapidly increasing the voltage to 30 mV.
e.
At +30 mV, V-g-Na-ch close and V-g-K-ch open fully.
- b
- c
- d
- e
- a
The summation of inhibitory stimulation and excitatory stimulation by presynaptic neurons takes place in which region of the neuron?
a.
in the axon
b.
at the axon hillock
c.
in the cell body and dendrites
d.
in the axon terminals
b.
at the axon hillock
The generation of the first action potential takes place in which region of the neuron?
a.
in dendrites
b.
in the cell body
c.
in the axon
d.
at the axon hillock
e.
in the axon terminals
d.
at the axon hillock
Place in chronological order the steps describing an EPSP
a.
Ach binds to a cholinergic receptor on Ch-g-Na-channels.
b.
Ch-g-Na-ch open partially.
c.
Na+ ions trickle into the post-synaptic neuron.
d.
The influx of position ions into the post-synaptic neuron increases its potential difference.
- a
- b
- c
- d
Match the post synaptic events with their definition.
spacial summation
temporal summation
excitatory postsynaptic potential (EPSP)
inhibitory postsynaptic potential (IPSP)
a. When a post synapic neuron is simultaneously stimulated by a number of presynaptic neurons.
b. When a post synapic neuron is stimulated repeatedly by one of many presynaptic neurons, without returning to resting potential between stimulations.
c. When a post synaptic neuron is stimulated by a single presynaptic neuron, such that the post synaptic neuron’s voltage increases closer towards the activation threshold.
d. When a post synaptic neuron is stimulated by a single presynaptic neuron, such that the post synaptic neuron’s voltage decreases further away from the activation threshold.
a. spacial summation
b. temporal summation
c. excitatory postsynaptic potential (EPSP)
d. inhibitory postsynaptic potential (IPSP)
Place in chronological order the steps describing an IPSP
GABA binds to a GABA receptor on a Ch-g-K-ch.
Ch-g-K-ch open partially.
K+ ions trickle out of the post-synaptic neuron.
The efflux of position ions out of the post-synaptic neuron decreases its potential difference.
1, 2, 3, 4
The reason why graded potentials cannot propagate is because
Question 10Select one:
a.
ions cannot diffuse from the cell body to the axon hillock
b.
the number of ions that constitute the graded potential is so small that as the ions diffuse to even lower concentrations, their collective charge dissipates.
c.
Incorrect, graded potentials can propagate.
b.
the number of ions that constitute the graded potential is so small that as the ions diffuse to even lower concentrations, their collective charge dissipates.
During the exocytosis of neurotransmitter, kinesin transport proteins carry vesicles containing neurotransmitters along microtubules.
False
Place in the correct chronological sequence the cytoskeletal events that take place during the export of neurotransmitters.
a. Myosin V-actin interactions carry the vesicles from the microtubule to the cytoplasmic membrane.
b. Kinesin carries the vesicle along up to the end of the microtubule.
c. Myosin II- actin interactions reduce the size of the vesicle, emptying its contents.
d. Myosin II– actin interactions reposition the actin fibers that were parallel to the cytoplasmic membrane to a new orientation that is perpendicular to the cytoplasmic membrane.
- b
- d
- a
- c
Inhibitory neurotransmitters
a.
bind to neurotransmitter receptors on ch-g-K-ch of the post synaptic neuron
b.
open sodium channels embebbed in the membrane of the post synaptic neuron.
c.
increase the voltage of the post synaptic neuron
d.
enter the post synaptic neuron
a.
bind to neurotransmitter receptors on ch-g-K-ch of the post synaptic neuron
What triggers the influx of calcium ions into the synaptic terminal?
Select one:
a.
The accumulation of positive potassium ions increases the voltage of the synaptic terminal sufficiently to trigger the opening of v-g-ca-ch.
b.
Calcium ions binding to extracellular ch-g-ca-ch
c.
The accumulation of positive sodium ions increases the voltage of the synaptic terminal sufficiently to trigger the opening of v-g-ca-ch.
d.
Sodium ions binding to intracellular ch-g-ca-ch
a.
The accumulation of positive sodium ions increases the voltage of the synaptic terminal sufficiently to trigger the opening of v-g-ca-ch.
Place in chronological order the steps describing summation.
a.
Na+ ions accumulate at the intersection of multiple local currents from excitatory stimuli.
b.
In the cytoplasm Na+ ions diffuse from the stimulation sites in the dendrites and cell body towards the axon while K+ ions are lost at multiple sites of inhibitory from stimuli.
c.
The potential difference increases at the intersection of local currents.
d.
The potential difference reaches activation threshold and this increase in voltage is close enough to v-g-Na-channels.
- b
- a
- c
- d
If an inhibitory neurotransmitter decreases the voltage inside a postsynaptic neuron
Select one:
a.
the postsynaptic neuron is less polarized than it was initially.
b.
the postsynaptic neuron is more likely to depolarize.
c.
the postsynaptic neuron returns to resting potential instead of depolarizing
d.
the postsynaptic neuron is more likely to reach activation threshold at the axon hillock.
c.
the postsynaptic neuron returns to resting potential instead of depolarizing
Place in chronological order the steps describing the secretion of Ach.
a.
As the positively charged sodium ions rush from the axon to the synaptic terminal, the synaptic terminal’s voltage increases.
b.
Calcium ions mediate the remodelling of the actinomyosin cortex of the synaptic terminal to reduce the diffusion barrier and recruit synaptic vesicles from the center of the synaptic terminal.
c.
Calcium ions mediate the remodelling of the actinomyosin cortex to empty out the cargo of the synaptic vesicles.
d.
A voltage increase in the synaptic terminal triggers the opening of v-gated-Ca-ch.
e.
Calcium ions diffuse from the extracellular fluid into the synaptic terminal.
f.
The membrane of the synaptic vesicles merges with the cytoplasmic membrane of the synaptic terminal, releasing acethycholine into the synaptic cleft.
g.
Calcium ions signal the myosin proteins to stop tethering the synaptic vesicles to actin filaments and instead transport the vesicles along the filaments to their docking sites on the plasma membrane.
- a
- d
- e
- c
- g.
- b
- f
What triggers the exocytosis of neurotransmitter molecules from the synaptic vesicles in the synaptic terminal?
Select one:
a.
an influx of Ca ions into the synaptic terminal from the axon
b.
an influx of Ca ions into the synaptic terminal from the extracellular space
c.
an influx of K+ ions into the synaptic terminal from the axon
d.
an influx of Na+ ions into the synaptic terminal from the axon
b.
an influx of Ca ions into the synaptic terminal from the extracellular space
