Question 1

Which of the following best describes the difference between graded potentials and action potentials in terms of amplitude and summation?

Accepted Answer

Graded potentials have variable amplitude and can be summed, while action potentials are all-or-none and cannot be summed.

Question 2

A patient with multiple sclerosis (MS) is experiencing muscle weakness and loss of coordination. Which of the following best explains the physiological basis for these symptoms?

Accepted Answer

Destruction of myelin sheaths in the CNS slows or stops action potential conduction.

Question 3

Which ion movement is primarily responsible for generating an excitatory postsynaptic potential (EPSP)?

Accepted Answer

$\mathrm{Na^+}$ influx

Question 4

Temporal summation in neurons refers to:

Accepted Answer

A single synapse firing rapidly in succession to produce a larger postsynaptic potential.

Question 5

Which of the following is TRUE regarding ionotropic neurotransmitter receptors?

Accepted Answer

They directly open ion channels, causing immediate and brief responses.

Question 6

A neuron receives both excitatory and inhibitory inputs at the same time. What is the likely outcome if the inhibitory input is stronger?

Accepted Answer

The membrane potential will hyperpolarize, preventing an action potential.

Question 7

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

Accepted Answer

Myelin allows for saltatory conduction, where the action potential jumps between nodes of Ranvier.

Question 8

Which neurotransmitter receptor type is both ionotropic and found at the neuromuscular junction?

Accepted Answer

Nicotinic acetylcholine receptor

Question 9

Which of the following scenarios best illustrates spatial summation?

Accepted Answer

Multiple presynaptic neurons fire simultaneously at different locations on the postsynaptic neuron, combining their effects.

Question 10

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

Accepted Answer

They have a refractory period.

Question 11

Which neurotransmitter is most associated with inhibitory postsynaptic potentials (IPSPs) in the central nervous system?

Accepted Answer

Glycine

Question 12

A drug that acts as an antagonist at muscarinic acetylcholine receptors would most likely:

Accepted Answer

Block parasympathetic effects on heart and glands.

Question 13

Which of the following best describes the effect of beta blockers on the autonomic nervous system?

Accepted Answer

They reduce heart rate by blocking adrenergic receptors.

Question 14

Which of the following is TRUE about metabotropic neurotransmitter receptors?

Accepted Answer

They activate G-proteins, leading to production of second messengers such as $\mathrm{cAMP}$ or $\mathrm{Ca^{2+}}$.

Question 15

Which of the following would most likely result from the activation of GABA$_A$ receptors?

Accepted Answer

Hyperpolarization due to $\mathrm{Cl^-}$ influx

Question 16

Which of the following is a direct effect of activating nicotinic acetylcholine receptors?

Accepted Answer

Opening of $\mathrm{Na^+}$ channels and depolarization of the postsynaptic membrane

Question 17

Which of the following best explains why a single EPSP cannot induce an action potential in a postsynaptic neuron?

Accepted Answer

A single EPSP is too brief and small to bring the membrane potential to threshold.

Question 18

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

Accepted Answer

They can be depolarizing or hyperpolarizing.

Question 19

Which of the following neurotransmitters is primarily excitatory in the central nervous system and acts mainly through ionotropic receptors?

Accepted Answer

Glutamate

Lecture 15 - Impulse Transmission II: Postsynaptic Potentials, Graded vs. Action Potentials, Conduction Velocity, and Neurotransmitters

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