Q: If the resting potential of a neuron is $$-70\text{mV}$$ and the inside of the cell is $$40\text{mV}$$ while the outside is $$110\text{mV}$$, what is the mathematical difference in membrane potential?

$$110\text{mV} - 40\text{mV} = 70\text{mV}$$

Question 1

Which of the following best describes the difference between an action potential and a synaptic transmission?

Accepted Answer

Action potential is the electrical signal that travels within a neuron, while synaptic transmission is the chemical communication between neurons across the synaptic cleft.

Question 2

If the resting potential of a neuron is $$-70	ext{mV}$$ and the inside of the cell is $$40	ext{mV}$$ while the outside is $$110	ext{mV}$$, what is the mathematical difference in membrane potential?

Accepted Answer

$$110	ext{mV} - 40	ext{mV} = 70	ext{mV}$$

Question 3

During the rising phase of the action potential, which ions primarily enter the neuron and what is the effect on membrane polarity?

Accepted Answer

Sodium ions ($$Na^+) $$enter, making the cell less polar (depolarized).

Question 4

Which statement best explains the 'all-or-none' response of an action potential?

Accepted Answer

The neuron either fires a full action potential or does not fire at all, regardless of stimulus strength once threshold is reached.

Question 5

What is the effect of an excitatory post-synaptic potential (EPSP) on the post-synaptic membrane?

Accepted Answer

It depolarizes the membrane, increasing the likelihood of firing.

Question 6

If two EPSPs occur simultaneously at different locations on a neuron, what is the likely outcome?

Accepted Answer

The EPSPs will sum to produce a greater depolarization, increasing the chance of reaching threshold.

Question 7

Which process allows action potentials to travel faster along myelinated axons compared to unmyelinated axons?

Accepted Answer

Saltatory conduction

Question 8

A neuron receives both an EPSP and an IPSP at the same time. What is the most likely effect on the membrane potential?

Accepted Answer

The EPSP and IPSP will sum, and the net effect will depend on their relative magnitudes.

Question 9

Which of the following best describes the role of the synaptic cleft?

Accepted Answer

It is the gap between the pre-synaptic and post-synaptic neurons where neurotransmitters are released and received.

Question 10

During the falling phase of the action potential, which ion movement is primarily responsible for returning the membrane potential toward resting levels?

Accepted Answer

Efflux of potassium ions ($$K^+)$$

Question 11

Which of the following scenarios would most likely result in the neuron firing an action potential?

Accepted Answer

The sum of EPSPs and IPSPs brings the membrane potential above the threshold.

Question 12

If the threshold for firing an action potential is $$-55	ext{mV}$$, and the membrane potential after summing all inputs is $$-60	ext{mV}$$, what will happen?

Accepted Answer

The neuron will not fire an action potential.

Question 13

Which of the following is true about inhibitory post-synaptic potentials (IPSPs)?

Accepted Answer

They hyperpolarize the post-synaptic membrane, decreasing the likelihood of firing.

Question 14

A neuron is at rest at $$-70	ext{mV}. $$After receiving an EPSP, its membrane potential changes to $$-67	ext{mV}. $$What type of change has occurred?

Accepted Answer

Depolarization

Question 15

Which of the following best describes the refractory period of a neuron?

Accepted Answer

The period immediately after an action potential when the neuron cannot fire another action potential.

Question 16

Which of the following is a correct sequence of events during an action potential?

Accepted Answer

Depolarization, influx of $$Na^+$$, efflux of $$K^+$$, hyperpolarization

Question 17

Which of the following is NOT a function of the synapse?

Accepted Answer

Transmitting electrical signals within a neuron

Question 18

Which of the following best explains why saltatory conduction is faster than conduction in unmyelinated axons?

Accepted Answer

Action potentials jump from node to node, reducing the number of times the signal must be regenerated.

Question 19

Which of the following would most likely decrease the likelihood of a neuron firing an action potential?

Accepted Answer

A strong IPSP

Neural Communication: Action Potentials, Synapses, and Post-Synaptic Potentials

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