Question 1

Which of the following best describes the 'all-or-none' principle of action potentials?

Accepted Answer

Action potentials only occur if the graded depolarization reaches threshold; all action potentials generated are identical in magnitude.

Question 2

During the absolute refractory period, which of the following is true?

Accepted Answer

No action potential can be generated, regardless of the strength of the stimulus.

Question 3

Which equation correctly represents the Nernst equation for calculating the equilibrium potential for potassium ($$K^+) $$ions?

Accepted Answer

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

Question 4

A patient with multiple sclerosis experiences slowed neural conduction. Which of the following best explains this phenomenon?

Accepted Answer

Demyelination decreases membrane resistance, causing action potentials to fail to propagate efficiently.

Question 5

Which of the following is a key difference between graded potentials and action potentials?

Accepted Answer

Graded potentials can be depolarizing or hyperpolarizing, while action potentials are always depolarizing.

Question 6

Which type of axon would transmit an action potential the fastest?

Accepted Answer

A large-diameter, myelinated axon (Type A fiber)

Question 7

Which of the following neurotransmitters is primarily inhibitory in the CNS and is known to reduce anxiety?

Accepted Answer

Gamma Aminobutyric Acid (GABA)

Question 8

A patient is prescribed a selective serotonin reuptake inhibitor (SSRI). What is the primary effect of this medication at the synapse?

Accepted Answer

It increases the amount of serotonin in the synaptic cleft by blocking its reabsorption.

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 speed.

Question 10

Which of the following events occurs first during the generation of an action potential?

Accepted Answer

Voltage-gated sodium channels open, causing rapid depolarization.

Question 11

Which of the following is true regarding chemical synapses?

Accepted Answer

They transmit signals via neurotransmitters across a synaptic cleft.

Question 12

Which of the following best explains why a neuron cannot generate another action potential during the absolute refractory period?

Accepted Answer

Voltage-gated sodium channels are either open or inactivated and cannot be reopened.

Question 13

Which of the following is a characteristic of an excitatory postsynaptic potential (EPSP)?

Accepted Answer

It is a graded depolarization that brings the postsynaptic membrane closer to threshold.

Question 14

Which of the following best describes temporal summation?

Accepted Answer

Multiple stimuli from the same source arrive in rapid succession and their effects add together.

Question 15

Which of the following is true about the effect of axon diameter on action potential conduction speed?

Accepted Answer

Larger diameter axons conduct action potentials faster due to lower internal resistance.

Question 16

Which of the following is a function of neuromodulators such as opioids?

Accepted Answer

They produce long-term, slow-appearing effects and can relieve pain.

Question 17

Which of the following best describes presynaptic inhibition?

Accepted Answer

Axoaxonic synapse activity reduces neurotransmitter release from the presynaptic neuron.

Question 18

Which of the following neurotransmitters is released by adrenergic synapses and has an excitatory effect in the brain and ANS?

Accepted Answer

Norepinephrine (NE)

Question 19

Which of the following is true regarding the effect of acetylcholine (ACh) at a cholinergic synapse?

Accepted Answer

The effect depends on the properties of the postsynaptic receptor, not the neurotransmitter itself.

Neural Tissue: Action Potentials, Synaptic Transmission, and Information Processing

Study Guide - Practice Questions