Q: Which equation is used to calculate the equilibrium potential for potassium ($$E_K) in a $$neuron, given the concentrations inside and outside the cell?

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

Question 1

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

Accepted Answer

They insulate, nourish, and support neurons.

Question 2

A neuron receives a strong depolarizing stimulus that shifts its membrane potential from $$-70\ 	ext{mV} to$$ $$-55\ 	ext{mV}. $$What is most likely to occur next?

Accepted Answer

The neuron will reach threshold and generate an action potential.

Question 3

Which equation is used to calculate the equilibrium potential for potassium ($$E_K) in a $$neuron, given the concentrations inside and outside the cell?

Accepted Answer

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

Question 4

What is the primary mechanism by which the sodium-potassium pump maintains the resting membrane potential?

Accepted Answer

It actively transports Na+ out of the cell and K+ into the cell using ATP.

Question 5

During the refractory period after an action potential, why can't a second action potential be initiated?

Accepted Answer

The sodium channels are temporarily inactivated.

Question 6

Which of the following best explains why action potentials travel in only one direction along an axon?

Accepted Answer

Inactivated Na+ channels behind the zone of depolarization prevent backward propagation.

Question 7

Which of the following is a real-world example of saltatory conduction in vertebrates?

Accepted Answer

Rapid reflexes in humans, such as withdrawing a hand from a hot surface.

Question 8

A postsynaptic neuron receives inputs from multiple presynaptic neurons. Which process determines whether it will fire an action potential?

Accepted Answer

The spatial and temporal summation of EPSPs and IPSPs at the axon hillock.

Question 9

Which neurotransmitter is classified as an amino acid and is involved in excitatory signaling in the brain?

Accepted Answer

Glutamate

Question 10

What is the effect of binding a neurotransmitter to a metabotropic receptor on the postsynaptic cell?

Accepted Answer

It activates a signal transduction pathway involving a second messenger.

Question 11

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

Accepted Answer

They form the myelin sheath around axons, increasing signal conduction speed.

Question 12

A neuron is at resting potential. Which ion has the highest concentration inside the cell compared to outside?

Accepted Answer

K+

Question 13

Which of the following mechanisms is NOT involved in terminating neurotransmitter signaling at a chemical synapse?

Accepted Answer

Continuous release of neurotransmitter by the postsynaptic neuron.

Question 14

Which of the following statements about action potentials is correct?

Accepted Answer

Action potentials are all-or-none events with constant magnitude.

Question 15

A patient is exposed to a toxin that blocks voltage-gated Na+ channels. What is the most likely effect on their nervous system?

Accepted Answer

Action potentials will not be generated, leading to paralysis.

Question 16

Which of the following is a function of interneurons in the nervous system?

Accepted Answer

Integrate and interpret sensory input.

Question 17

Which process is illustrated when a neuron receives multiple EPSPs in rapid succession from the same presynaptic terminal, resulting in an action potential?

Accepted Answer

Temporal summation

Question 18

Which of the following ions is most responsible for the depolarization phase of the action potential?

Accepted Answer

Na+

Question 19

What is the effect of opening ligand-gated ion channels in the postsynaptic membrane?

Accepted Answer

It generates a postsynaptic potential by allowing ions to flow across the membrane.

Question 20

Which of the following best describes the chemical potential energy in a neuron at resting potential?

Accepted Answer

It is due to the concentration gradients of Na+ and K+ maintained by the sodium-potassium pump.

Neurons, Synapses, and Signaling: Structure and Function in Information Transfer

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