Question 1

Which of the following best describes the difference between graded potentials and action potentials in neurons?

Accepted Answer

Graded potentials are decremental and can summate, while action potentials are all-or-none and propagate without decrement.

Question 2

A neuron receives two simultaneous excitatory postsynaptic potentials (EPSPs) at different locations on its dendrites. What is this phenomenon called, and what is its effect?

Accepted Answer

Spatial summation; increases the likelihood of an action potential.

Question 3

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

Accepted Answer

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

Question 4

If voltage-gated sodium channels remained inactivated during the absolute refractory period, what would be the effect on neuronal signaling?

Accepted Answer

The neuron would be unable to fire another action potential until the channels reset, ensuring unidirectional propagation.

Question 5

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

Accepted Answer

Myelinated axons allow for saltatory conduction, where action potentials jump between nodes of Ranvier.

Question 6

Which of the following is true regarding excitatory postsynaptic potentials (EPSPs)?

Accepted Answer

EPSPs depolarize the postsynaptic membrane, increasing the likelihood of an action potential.

Question 7

A neurotransmitter binds to a postsynaptic receptor and causes a slow, prolonged response involving second messengers. Which type of receptor is most likely involved?

Accepted Answer

Metabotropic receptor

Question 8

Which of the following scenarios would most likely result in temporal summation at the axon hillock?

Accepted Answer

Multiple EPSPs arrive at the axon hillock from the same presynaptic neuron in rapid succession.

Question 9

Which of the following best describes the decremental nature of graded potentials?

Accepted Answer

Graded potentials decrease in amplitude as they travel away from the site of origin.

Question 10

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

Accepted Answer

Action potential arrival, neurotransmitter release, postsynaptic receptor activation

Question 11

Which of the following would most likely occur if two graded potentials (one EPSP and one IPSP) arrive simultaneously at the axon hillock?

Accepted Answer

The EPSP and IPSP would summate, and the net effect would depend on their relative magnitudes.

Question 12

Which of the following is true about ionotropic receptors?

Accepted Answer

They are ligand-gated ion channels that allow ions to flow directly across the membrane.

Question 13

Which of the following factors does NOT influence the conduction velocity of an action potential along an axon?

Accepted Answer

Number of dendrites

Question 14

A postsynaptic cell receives a neurotransmitter that opens chloride channels. What is the most likely effect?

Accepted Answer

Hyperpolarization and decreased likelihood of action potential

Question 15

Which of the following best describes the role of the axon hillock in neural integration?

Accepted Answer

It is the site where the summation of graded potentials determines whether an action potential will be initiated.

Question 16

Which of the following is a property unique to action potentials compared to graded potentials?

Accepted Answer

They are all-or-none events that propagate without decrement.

Question 17

Which of the following best describes the effect of an inhibitory postsynaptic potential (IPSP)?

Accepted Answer

It hyperpolarizes the postsynaptic membrane, decreasing the likelihood of an action potential.

Question 18

Which of the following is true regarding metabotropic receptors?

Accepted Answer

They are G-protein coupled receptors that activate intracellular signaling cascades.

Question 19

A neuron has a resting membrane potential of $$-65 mV$$, $$E_K = -85 mV$$, and $$E_{Na} = +55 mV. $$Using the net electrochemical force equation $$F = V_m - E_{ion}$$, what is the net force on K$$^+$$ and Na$$^+$$ ions, respectively?

Accepted Answer

$$150$$ and $$-135$$

Neural Signaling: Synaptic Transmission, Graded Potentials, and Action Potentials

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