Question 1

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

Accepted Answer

Electrical synapses transmit signals rapidly and synchronously via gap junctions, while chemical synapses rely on neurotransmitter release for communication.

Question 2

A patient is exposed to a neurotoxin that blocks voltage-gated sodium channels. What is the most likely effect on nerve impulse transmission?

Accepted Answer

Action potentials will be unable to propagate along the axon, resulting in loss of nerve impulse transmission.

Question 3

Which equation best represents the calculation of the resting membrane potential using the concentrations of potassium and sodium ions?

Accepted Answer

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

Question 4

Which of the following factors would most likely slow down the conduction velocity of a nerve impulse?

Accepted Answer

Decreasing the temperature

Question 5

During the events at a chemical synapse, which process is responsible for the release of neurotransmitters into the synaptic cleft?

Accepted Answer

Exocytosis

Question 6

A person sits on their leg for an extended period and experiences numbness. Which mechanism best explains this phenomenon?

Accepted Answer

Continuous pressure interrupts blood circulation, reducing oxygen and nutrient delivery to neurons.

Question 7

Which type of ion channel opens in response to a change in membrane potential?

Accepted Answer

Voltage-gated channel

Question 8

Which neurotransmitter is classified as an amino acid and is primarily inhibitory in the central nervous system?

Accepted Answer

GABA (gamma-aminobutyric acid)

Question 9

Which of the following best describes saltatory conduction?

Accepted Answer

Action potentials jump from one node of Ranvier to the next, increasing conduction velocity.

Question 10

Which neurotoxin is commonly found in improperly canned foods and can cause paralysis by blocking acetylcholine release?

Accepted Answer

Botulinum toxin

Question 11

A neuron is stimulated and an action potential is generated. Which event occurs first?

Accepted Answer

Depolarization: $$Na^+$$ ions rush into the cell

Question 12

Which of the following is NOT a common effect of neurotoxins on the nervous system?

Accepted Answer

Enhancement of myelin sheath formation

Question 13

Which of the following would most likely increase the excitability of a neuron?

Accepted Answer

Increasing the permeability of the membrane to sodium ions

Question 14

Which neurotransmitter is classified as a monoamine and is associated with reward and addictive behaviors?

Accepted Answer

Dopamine

Question 15

Which of the following best explains why cold temperatures can cause numbness in extremities?

Accepted Answer

Cold reduces membrane permeability to sodium ions, blocking nerve impulses.

Question 16

Which of the following is TRUE regarding the sodium-potassium pump in neurons?

Accepted Answer

It moves $$Na^+$$ ions out of the cell and $$K^+$$ ions into the cell, helping maintain the resting membrane potential.

Question 17

Which of the following scenarios would most likely result in a decrease in nerve conduction velocity?

Accepted Answer

Loss of myelin sheath due to disease

Question 18

Which neurotransmitter is classified as a soluble gas and is not stored in vesicles?

Accepted Answer

Nitric oxide

Question 19

A patient is exposed to tetrodotoxin from a pufferfish. What is the primary mechanism by which this neurotoxin affects neurons?

Accepted Answer

It blocks voltage-gated sodium channels, preventing action potential propagation.

Question 20

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

Accepted Answer

Action potential arrives at axon terminal → voltage-gated $$Ca^{2+}$$ channels open → neurotransmitter released by exocytosis → neurotransmitter binds to postsynaptic receptor

Chapter 12 – Neurophysiology: Synapses, Neurotransmitters, and Nerve Impulse Transmission

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