Question 1

Which of the following best describes the difference between ionotropic and metabotropic receptors in synaptic transmission?

Accepted Answer

Ionotropic receptors directly open ion channels, resulting in fast synaptic transmission, while metabotropic receptors activate G-proteins and second messengers, leading to slower, amplified responses.

Question 2

A neurotransmitter binds to a postsynaptic receptor and increases the membrane's permeability to Na	extsuperscript{+}. What is the most likely effect on the postsynaptic cell's membrane potential ($V_m$)?

Accepted Answer

The membrane potential will become more positive, moving towards the equilibrium potential for Na	extsuperscript{+} ($E_{Na}$).

Question 3

Which neurotransmitter is primarily responsible for stimulating muscle contraction at the neuromuscular junction?

Accepted Answer

Acetylcholine (ACh)

Question 4

A patient is given a drug that blocks the reuptake of serotonin (5-HT) at synapses. What is the expected effect on synaptic transmission?

Accepted Answer

Increased duration and intensity of serotonin's effect on the postsynaptic cell.

Question 5

Which of the following equations is used to calculate the equilibrium potential for a single ion across a membrane?

Accepted Answer

$E_{ion} = \frac{RT}{zF} \ln \left( \frac{[ion]_{out}}{[ion]_{in}} \right)$

Question 6

If a postsynaptic cell receives simultaneous excitatory postsynaptic potentials (EPSPs) from multiple presynaptic neurons, what process is occurring?

Accepted Answer

Spatial summation

Question 7

Which neurotransmitter is most commonly associated with inhibitory synaptic transmission in the central nervous system?

Accepted Answer

GABA

Question 8

A postsynaptic potential drives the membrane potential ($V_m$) towards $E_{K}$, making the cell more negative. What type of synaptic potential is this?

Accepted Answer

Inhibitory postsynaptic potential (IPSP)

Question 9

Which of the following best explains why the effect of a neurotransmitter depends on the receptor type rather than the neurotransmitter itself?

Accepted Answer

The receptor determines which ion channels open or which signaling pathways are activated, leading to different cellular responses.

Question 10

Which process is responsible for the termination of neurotransmitter action at the synapse?

Accepted Answer

Reuptake by pumps and transporters, enzymatic degradation, or diffusion away from the synapse.

Question 11

A neuron receives two EPSPs in rapid succession at the same synapse. What is this phenomenon called?

Accepted Answer

Temporal summation

Question 12

Which neurotransmitter is most associated with the 'fight or flight' response?

Accepted Answer

Norepinephrine (NE)

Question 13

What is the role of the axon initial segment (trigger zone) in neuronal signaling?

Accepted Answer

It is the site where action potentials are initiated if the threshold is reached.

Question 14

Which of the following is a lipid-derived neurotransmitter?

Accepted Answer

Cannabinoids

Question 15

If the membrane is only permeable to K	extsuperscript{+}, what equation would you use to calculate the membrane potential?

Accepted Answer

$E_{K} = \frac{RT}{zF} \ln \left( \frac{[K^+]_{out}}{[K^+]_{in}} \right)$

Question 16

Which neurotransmitter is most widely distributed and excitatory in the central nervous system?

Accepted Answer

Glutamate

Question 17

A postsynaptic cell receives both EPSPs and IPSPs simultaneously. What determines whether an action potential will be generated?

Accepted Answer

The net effect of all graded potentials at the trigger zone determines if the threshold is reached for an action potential.

Question 18

Which of the following is NOT a mechanism for neurotransmitter inactivation?

Accepted Answer

Binding to postsynaptic receptors

Question 19

Which neurotransmitter is involved in reward and motivation pathways in the brain?

Accepted Answer

Dopamine (DA)

Question 20

A neuron is exposed to a drug that mimics the action of an endogenous neurotransmitter at its receptor. What is this type of drug called?

Accepted Answer

Agonist

Synaptic Transmission and Graded Potentials: Study Notes for Anatomy & Physiology

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