Question 1

Which of the following best describes the resting membrane potential (RMP) of a neuron, and what is its typical value?

Accepted Answer

It is the electrical potential difference across the plasma membrane when the neuron is inactive, typically around $$-70\ \mathrm{mV}.$$

Question 2

Which type of ion channel is primarily responsible for the rapid depolarization phase of the action potential in neurons?

Accepted Answer

Voltage-gated sodium ($$Na^+) $$channels

Question 3

A patient is experiencing muscle weakness due to a genetic defect in the Na$$^+/K$^+$$ pump. Which of the following best explains how this defect affects the neuron’s ability to transmit electrical signals?

Accepted Answer

The neuron cannot maintain the resting membrane potential, making it less excitable.

Question 4

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

Accepted Answer

Graded potentials can summate and vary in amplitude, while action potentials are all-or-none and have a fixed amplitude.

Question 5

During the repolarization phase of an action potential, which ion movement is primarily responsible for returning the membrane potential toward its resting value?

Accepted Answer

$$K^+$$ ions move out of the cell through voltage-gated channels.

Question 6

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

Accepted Answer

Myelinated axons enable saltatory conduction, allowing action potentials to jump between nodes of Ranvier.

Question 7

A neuron receives simultaneous excitatory and inhibitory inputs. Which process determines whether the neuron will fire an action potential?

Accepted Answer

Integration of both temporal and spatial summation at the axon hillock

Question 8

Which of the following is TRUE regarding the all-or-none principle of action potentials?

Accepted Answer

If the threshold is reached, an action potential will be generated with a fixed amplitude.

Question 9

Which of the following best describes the function of astrocytes in the central nervous system (CNS)?

Accepted Answer

They form the blood-brain barrier and regulate the extracellular environment.

Question 10

A neurotransmitter binds to its receptor on the postsynaptic membrane and causes an influx of $$Cl^-$$ ions. What is the likely effect on the postsynaptic neuron?

Accepted Answer

It will hyperpolarize and become less likely to fire an action potential.

Question 11

Which of the following best explains the difference between anterograde and retrograde axonal transport?

Accepted Answer

Anterograde transport moves materials from the soma to the axon terminal, while retrograde transport moves materials from the axon terminal to the soma.

Question 12

Which of the following structures is the primary site for the initiation of an action potential in a neuron?

Accepted Answer

Axon hillock

Question 13

Which of the following best describes the role of microglia in the CNS?

Accepted Answer

They act as immune cells, removing debris and pathogens.

Question 14

A patient is given a drug that blocks voltage-gated $$Na^+$$ channels. What is the most likely effect on neuronal signaling?

Accepted Answer

Action potentials will be unable to initiate or propagate.

Question 15

Which of the following is a characteristic of chemical synapses but NOT electrical synapses?

Accepted Answer

Presence of synaptic delay due to neurotransmitter release

Question 16

Which of the following best describes the function of the Na$$^+/K$^+$$ pump in maintaining neuronal function?

Accepted Answer

It actively transports $$3\ Na^+$$ out and $$2\ K^+$$ into the cell, maintaining the resting membrane potential.

Question 17

Which of the following is TRUE about the refractory period of a neuron?

Accepted Answer

It is the time during which a neuron cannot fire another action potential, regardless of stimulus strength.

Question 18

Which of the following best explains the difference between EPSP and IPSP?

Accepted Answer

EPSP brings the membrane potential closer to threshold, while IPSP moves it further away.

Question 19

Which of the following is a function of oligodendrocytes in the CNS?

Accepted Answer

They produce myelin sheaths for multiple axons.

Chapter 11: Introduction to the Nervous System and Nervous Tissue – Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard