Q: During the depolarisation phase of an action potential, which ion channels open, and what is the resulting effect on membrane potential?

Voltage-gated Na\textsuperscript{+} channels open, causing the membrane potential to become more positive.

Q: What is the typical resting membrane potential of a neuron, and which ions are primarily responsible for maintaining it?

$$-70\ \mathrm{mV}$$, maintained by K\textsuperscript{+} efflux and Na\textsuperscript{+}/K\textsuperscript{+} ATPase

Q: What triggers the release of neurotransmitters from the presynaptic neuron into the synaptic cleft?

Influx of Ca\textsuperscript{2+} ions through voltage-gated channels

Q: Which of the following best describes the role of the Na\textsuperscript{+}/K\textsuperscript{+} ATPase in neurons?

It pumps Na\textsuperscript{+} out and K\textsuperscript{+} into the cell, maintaining the resting membrane potential.

Question 1

During the depolarisation phase of an action potential, which ion channels open, and what is the resulting effect on membrane potential?

Accepted Answer

Voltage-gated Na	extsuperscript{+} channels open, causing the membrane potential to become more positive.

Question 2

What is the typical resting membrane potential of a neuron, and which ions are primarily responsible for maintaining it?

Accepted Answer

$$-70\ \mathrm{mV}$$, maintained by K	extsuperscript{+} efflux and Na	extsuperscript{+}/K	extsuperscript{+} ATPase

Question 3

Which neurotransmitter is the main inhibitory neurotransmitter in the central nervous system?

Accepted Answer

GABA

Question 4

What triggers the release of neurotransmitters from the presynaptic neuron into the synaptic cleft?

Accepted Answer

Influx of Ca	extsuperscript{2+} ions through voltage-gated channels

Question 5

After neurotransmitters are released into the synaptic cleft, which of the following is NOT a way they are removed?

Accepted Answer

Absorbed by postsynaptic mitochondria

Question 6

During the repolarisation phase of the action potential, what happens to the membrane potential and which channels are involved?

Accepted Answer

Membrane potential returns to $$-70\ \mathrm{mV}$$ due to opening of voltage-gated K	extsuperscript{+} channels

Question 7

Which of the following best describes the role of the Na	extsuperscript{+}/K	extsuperscript{+} ATPase in neurons?

Accepted Answer

It pumps Na	extsuperscript{+} out and K	extsuperscript{+} into the cell, maintaining the resting membrane potential.

Question 8

A patient is given a drug that blocks voltage-gated Ca	extsuperscript{2+} channels in neurons. What is the most likely effect on synaptic transmission?

Accepted Answer

Neurotransmitter release will be inhibited.

Question 9

Which of the following sequences correctly describes the sensory (afferent) pathway from a receptor to the primary sensory cortex?

Accepted Answer

Receptor → peripheral nerve → dorsal root ganglion → dorsal horn → thalamus → primary sensory cortex

Question 10

Which neurotransmitter is the main excitatory neurotransmitter in the central nervous system?

Accepted Answer

Glutamate

Question 11

What is the effect of binding of neurotransmitter to postsynaptic receptors?

Accepted Answer

It triggers a graded potential that can either lead to or prevent an action potential.

Question 12

Which of the following best describes the motor (efferent) pathway from the primary motor cortex to a muscle fibre?

Accepted Answer

Upper motor neuron in cortex → crosses over in medulla → lower motor neuron in ventral horn → peripheral nerve → muscle fibre

Question 13

If the threshold potential is not reached in a neuron, what will happen?

Accepted Answer

No action potential will be generated.

Question 14

Which of the following is a correct statement about the direction of ion movement during the repolarisation phase of an action potential?

Accepted Answer

K	extsuperscript{+} ions move out of the cell.

Question 15

A mutation causes the Na	extsuperscript{+}/K	extsuperscript{+} ATPase to stop functioning. What is the most likely consequence for the neuron?

Accepted Answer

The neuron will be unable to maintain its resting membrane potential.

Question 16

Which of the following best explains why neurotransmitters can have both excitatory and inhibitory effects on the postsynaptic cell?

Accepted Answer

The effect depends on the type of receptor the neurotransmitter binds to.

Question 17

Which equation best represents the Nernst equation for calculating the equilibrium potential of an ion?

Accepted Answer

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

Question 18

Which of the following would most likely result from excessive activation of glutamate receptors in the CNS?

Accepted Answer

Excitotoxicity and potential neuronal damage

Question 19

A patient with a genetic mutation affecting voltage-gated K	extsuperscript{+} channels is likely to experience which of the following?

Accepted Answer

Delayed repolarisation after an action potential

Action Potentials, Synaptic Transmission, and Neural Pathways: Study Notes for Anatomy & Physiology

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