PSL 310: UNIT 2 Exam Questions and
All Solved Solutions 2026 Updated.
typical synapse - Answer from axon to cell body or dendrites
synaptic cleft - Answer space in between neurons
presynaptic neuron - Answer conducts impulse to the synapse
postsynaptic neuron - Answer conducts impulse away from the synapse
synaptic knob - Answer axon terminal of presynaptic neuron with swelling on the end.
filled with sacs called synaptic vesicles
why is the chemical synapse almost always one way? - Answer it goes from presynaptic to
postsynaptic
-neurotransmitters only come from the synaptic knob on the presynaptic neuron and the
receptor is only located on the subsynaptic membrane of the presynaptic neuron.
Acetylcholine (ACh) - Answer in CNS, in ANS, released at skeletal muscle cells
Norepinephrine (NE) - Answer in CNS, in ANS
How is ACh broken down? - Answer ACh-ase is a receptor on the subsynaptic membrane that
splits ACh apart
what happens if you inhibit ACh-ase - Answer there will be continual stimulation of the
membrane, not allowing for a new signal to fire off. New signals are needed for new muscle
contracts, like taking another breath.
How are ACh-ase inhibitors used to treat Alzheimers - Answer ACh is low in the brain in
Alzheimers (it is used for memory and learning). Inhibitors allows for more release of ACh,
slowing the symptoms of the disease.
How is NE broken down/ removed - Answer Reuptake back into the presynaptic knob is the
most important way NE is removed
it is also broken down by MAO and COMT enzymes
, why are neurotransmitters removed or broken down - Answer to stop stimulation of the
membrane/ to stop signals/ "clean the slate" for a new signal
EPSP - Answer depolarization
caused by cation channels opening, same one for Na+ and K+
IPSP - Answer hyperpolarization
caused by increased K+ permeability but not Na+ permeability
why is a single synapse always excitatory or always inhibitory? - Answer the synaptic knob
releases the same chemical/ transmitter that has the same effect on the postsynaptic cell.
What is the function of EPSPs - Answer to trigger APs and get the membrane to threshold at
the axon hillox
how much one EPSP changes the RMP vs several - Answer one changes it about .5mV and 30
changes it enough to reach threshold
why is threshold lowest at the axon hillox? - Answer there are more voltage gated Na+
channels at the axon hillox than any other part of the neuron
a change in RMP has more effect here
What is the function of IPSPs - Answer to prevent AP
to hyper polarize the depolarization caused by EPSPs
True or False: GABA is an excitatory neurotransmitter - Answer FALSE: GABA is inhibitory
spatial summation - Answer different knobs firing off at the same time can sum together
temporal summation - Answer the same knob that fires off before the second input is
finished can sum together
presynaptic inhibition - Answer axon to axon synapse
when one axon decreases neurotransmitter release from another axon
can affect afferent fibers
All Solved Solutions 2026 Updated.
typical synapse - Answer from axon to cell body or dendrites
synaptic cleft - Answer space in between neurons
presynaptic neuron - Answer conducts impulse to the synapse
postsynaptic neuron - Answer conducts impulse away from the synapse
synaptic knob - Answer axon terminal of presynaptic neuron with swelling on the end.
filled with sacs called synaptic vesicles
why is the chemical synapse almost always one way? - Answer it goes from presynaptic to
postsynaptic
-neurotransmitters only come from the synaptic knob on the presynaptic neuron and the
receptor is only located on the subsynaptic membrane of the presynaptic neuron.
Acetylcholine (ACh) - Answer in CNS, in ANS, released at skeletal muscle cells
Norepinephrine (NE) - Answer in CNS, in ANS
How is ACh broken down? - Answer ACh-ase is a receptor on the subsynaptic membrane that
splits ACh apart
what happens if you inhibit ACh-ase - Answer there will be continual stimulation of the
membrane, not allowing for a new signal to fire off. New signals are needed for new muscle
contracts, like taking another breath.
How are ACh-ase inhibitors used to treat Alzheimers - Answer ACh is low in the brain in
Alzheimers (it is used for memory and learning). Inhibitors allows for more release of ACh,
slowing the symptoms of the disease.
How is NE broken down/ removed - Answer Reuptake back into the presynaptic knob is the
most important way NE is removed
it is also broken down by MAO and COMT enzymes
, why are neurotransmitters removed or broken down - Answer to stop stimulation of the
membrane/ to stop signals/ "clean the slate" for a new signal
EPSP - Answer depolarization
caused by cation channels opening, same one for Na+ and K+
IPSP - Answer hyperpolarization
caused by increased K+ permeability but not Na+ permeability
why is a single synapse always excitatory or always inhibitory? - Answer the synaptic knob
releases the same chemical/ transmitter that has the same effect on the postsynaptic cell.
What is the function of EPSPs - Answer to trigger APs and get the membrane to threshold at
the axon hillox
how much one EPSP changes the RMP vs several - Answer one changes it about .5mV and 30
changes it enough to reach threshold
why is threshold lowest at the axon hillox? - Answer there are more voltage gated Na+
channels at the axon hillox than any other part of the neuron
a change in RMP has more effect here
What is the function of IPSPs - Answer to prevent AP
to hyper polarize the depolarization caused by EPSPs
True or False: GABA is an excitatory neurotransmitter - Answer FALSE: GABA is inhibitory
spatial summation - Answer different knobs firing off at the same time can sum together
temporal summation - Answer the same knob that fires off before the second input is
finished can sum together
presynaptic inhibition - Answer axon to axon synapse
when one axon decreases neurotransmitter release from another axon
can affect afferent fibers
