Q: Which equation would you use to calculate the equilibrium potential for potassium ($$K^+) $$across a neuronal membrane?

$$E_K = 62 \log \frac{[K^+]_{\text{outside}}}{[K^+]_{\text{inside}}}$$

Question 1

Which of the following best describes the role of glial cells in the nervous system?

Accepted Answer

They insulate, nourish, and support neurons.

Question 2

A neuron at rest has a membrane potential of approximately $$-70\ \mathrm{mV}. $$Which of the following is primarily responsible for maintaining this resting potential?

Accepted Answer

The active transport of Na$$^+$$ out and K$$^+ in by $$the sodium-potassium pump.

Question 3

Which equation would you use to calculate the equilibrium potential for potassium ($$K^+) $$across a neuronal membrane?

Accepted Answer

$$E_K = 62 \log \frac{[K^+]_{	ext{outside}}}{[K^+]_{	ext{inside}}}$$

Question 4

During an action potential, which event occurs immediately after the membrane potential reaches threshold?

Accepted Answer

Voltage-gated Na$$^+$$ channels open, causing rapid depolarization.

Question 5

Why do action potentials only travel in one direction along an axon?

Accepted Answer

The refractory period prevents Na$$^+$$ channels from reopening immediately behind the action potential.

Question 6

Which of the following best explains why myelinated axons conduct action potentials faster than unmyelinated axons?

Accepted Answer

Action potentials jump between nodes of Ranvier in a process called saltatory conduction.

Question 7

A patient is exposed to a toxin that blocks voltage-gated Ca$$^{2+}$$ channels at the synaptic terminal. What is the most likely effect on synaptic transmission?

Accepted Answer

Neurotransmitter release will be inhibited.

Question 8

Which of the following scenarios would most likely result in an inhibitory postsynaptic potential (IPSP)?

Accepted Answer

Opening of ligand-gated K$$^+ or Cl$^-$$ channels.

Question 9

If a postsynaptic neuron receives two excitatory signals in rapid succession at the same synapse, what is this process called?

Accepted Answer

Temporal summation

Question 10

Which mechanism is NOT involved in the termination of neurotransmitter signaling at a chemical synapse?

Accepted Answer

Continuous activation of ligand-gated ion channels

Question 11

Which of the following best describes the difference between electrical and chemical synapses?

Accepted Answer

Chemical synapses use neurotransmitters, while electrical synapses use gap junctions.

Question 12

Which of the following neurotransmitters is classified as a biogenic amine?

Accepted Answer

Dopamine

Question 13

A neuron receives both excitatory and inhibitory inputs from multiple presynaptic neurons. What determines whether the postsynaptic neuron will fire an action potential?

Accepted Answer

The sum of all EPSPs and IPSPs at the axon hillock

Question 14

Which of the following is a correct sequence of events during synaptic transmission at a chemical synapse?

Accepted Answer

Action potential arrives at synaptic terminal → Ca$$^{2+}$$ influx → neurotransmitter release → postsynaptic receptor activation

Question 15

Which of the following would most likely increase the speed of action potential conduction in a neuron?

Accepted Answer

Adding a myelin sheath

Question 16

Which of the following best explains why the resting membrane potential is negative?

Accepted Answer

K$$^+$$ diffuses out of the cell, leaving behind negatively charged ions.

Question 17

Which of the following is a property of action potentials but NOT graded potentials?

Accepted Answer

They are all-or-none events.

Question 18

A drug that blocks the reuptake of serotonin at synapses would most likely have which effect?

Accepted Answer

Increase the duration of serotonin signaling.

Question 19

Which of the following is TRUE about metabotropic receptors?

Accepted Answer

They activate signal transduction pathways involving second messengers.

Neurons, Synapses, and Signaling: Structure and Function in the Nervous System

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