Question 1

Which of the following best describes the role of the axon hillock in a neuron?

Accepted Answer

It is the trigger zone where action potentials are initiated if the threshold is reached.

Question 2

Which glial cell type is responsible for forming myelin sheaths in the central nervous system (CNS)?

Accepted Answer

Oligodendrocytes

Question 3

A patient suffers a peripheral nerve injury that severs the axon but leaves the cell body intact. What is the most likely outcome?

Accepted Answer

The axon may regenerate, especially in the PNS, restoring some function.

Question 4

Which equation is used to calculate the equilibrium potential for a specific ion across a membrane?

Accepted Answer

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

Question 5

During the rising phase of an action potential, which ion moves and in which direction?

Accepted Answer

Sodium ions move into the cell.

Question 6

Which of the following is TRUE about graded potentials?

Accepted Answer

They lose strength due to current leak and cytoplasmic resistance.

Question 7

What is the main difference between chemical and electrical synapses?

Accepted Answer

Chemical synapses use neurotransmitters to transmit signals across the synaptic cleft.

Question 8

Which of the following best describes the absolute refractory period of an action potential?

Accepted Answer

A period when no stimulus, regardless of strength, can initiate another action potential.

Question 9

Which type of ion channel opens in response to physical deformation of the membrane?

Accepted Answer

Mechanically gated channel

Question 10

A neuron receives multiple subthreshold graded potentials at its dendrites. What is the most likely outcome at the axon hillock?

Accepted Answer

The membrane potential will remain below threshold and no action potential will occur.

Question 11

Which glial cell type acts as the main immune defense in the central nervous system?

Accepted Answer

Microglia

Question 12

Which of the following best explains why action potentials do not lose strength as they travel along the axon?

Accepted Answer

They are continuously regenerated by voltage-gated ion channels along the axon.

Question 13

Which part of the neuron is primarily responsible for receiving incoming signals?

Accepted Answer

Dendrites

Question 14

What is the effect of myelin on the conduction of action potentials?

Accepted Answer

It allows action potentials to jump between nodes of Ranvier, increasing speed.

Question 15

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

Accepted Answer

Depolarization, sodium channels close, potassium channels open, repolarization

Question 16

Which of the following best describes the function of astrocytes in the CNS?

Accepted Answer

They help maintain the blood-brain barrier and regulate extracellular ion concentrations.

Question 17

Which of the following is TRUE about the enteric nervous system?

Accepted Answer

It is a network of neurons in the walls of the digestive tract that can function autonomously.

Question 18

Which of the following is a function of satellite cells in the peripheral nervous system?

Accepted Answer

They provide support and nutrition to neuron cell bodies in ganglia.

Question 19

Which of the following best describes the difference between sensory (afferent) and motor (efferent) neurons?

Accepted Answer

Sensory neurons carry signals from receptors to the CNS; motor neurons carry signals from the CNS to effectors.

Question 20

Which of the following is a property of graded potentials that distinguishes them from action potentials?

Accepted Answer

They can be depolarizing or hyperpolarizing and vary in amplitude.

Membrane Potential and Organization of the Nervous System: Study Notes for Anatomy & Physiology

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