Q: Which of the following equations correctly represents the movement of ions by the sodium-potassium pump?

$$3\ \mathrm{Na}^+_{\text{in}} \rightarrow 3\ \mathrm{Na}^+_{\text{out}}$$ and $$2\ \mathrm{K}^+_{\text{out}} \rightarrow 2\ \mathrm{K}^+_{\text{in}}$$

Question 1

Which of the following best describes the role of the sodium-potassium pump in maintaining the resting membrane potential of a neuron?

Accepted Answer

It pumps three sodium ions out of the cell and two potassium ions into the cell, maintaining a negative charge inside.

Question 2

During which phase of the action potential are voltage-gated sodium channels open and sodium ions rapidly entering the neuron?

Accepted Answer

Depolarization

Question 3

Which glial cell type is responsible for myelinating axons in the central nervous system (CNS)?

Accepted Answer

Oligodendrocytes

Question 4

What is the main difference between an excitatory postsynaptic potential (EPSP) and an inhibitory postsynaptic potential (IPSP)?

Accepted Answer

EPSPs depolarize the membrane, while IPSPs hyperpolarize it.

Question 5

Which of the following best explains why action potentials are considered 'all-or-none' events?

Accepted Answer

Once threshold is reached, an action potential of fixed size is generated regardless of stimulus strength.

Question 6

What is the function of the absolute refractory period in a neuron?

Accepted Answer

It prevents the neuron from firing another action potential until sodium channels reset.

Question 7

A patient has a demyelinating disease affecting the peripheral nervous system. Which cell type is most likely damaged?

Accepted Answer

Schwann cells

Question 8

Which of the following equations correctly represents the movement of ions by the sodium-potassium pump?

Accepted Answer

$$3\ \mathrm{Na}^+_{	ext{in}} ightarrow 3\ \mathrm{Na}^+_{	ext{out}}$$ and $$2\ \mathrm{K}^+_{	ext{out}} ightarrow 2\ \mathrm{K}^+_{	ext{in}}$$

Question 9

Which of the following best describes the process of repolarization during an action potential?

Accepted Answer

Potassium channels open and potassium exits the cell, restoring negative membrane potential.

Question 10

A neuron receives multiple EPSPs and IPSPs at the same time. What process determines whether an action potential will be generated?

Accepted Answer

Integration of all postsynaptic potentials at the axon hillock

Question 11

Which of the following is NOT a function of glial cells?

Accepted Answer

Transmitting electrical signals over long distances

Question 12

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

Accepted Answer

Action potentials jump from node to node (saltatory conduction) in myelinated axons.

Question 13

Which of the following scenarios best illustrates the concept of the relative refractory period?

Accepted Answer

A neuron can fire another action potential, but only if the stimulus is stronger than usual.

Question 14

Which of the following best describes the propagation of an action potential along an axon?

Accepted Answer

The action potential is regenerated at each segment of the axon, moving in one direction toward the axon terminal.

Question 15

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

Accepted Answer

Depolarization → Repolarization → Hyperpolarization → Resting potential

Question 16

If a neuron is exposed to a toxin that blocks voltage-gated potassium channels, what would most likely happen during an action potential?

Accepted Answer

The neuron would not repolarize efficiently, prolonging the action potential.

Question 17

Which of the following best describes the function of astrocytes in the nervous system?

Accepted Answer

They provide structural and metabolic support for neurons and help maintain the blood-brain barrier.

Question 18

A neuron is at rest with a membrane potential of $$-70\ \mathrm{mV}. If $$the membrane becomes more negative (e.g., $$-80\ \mathrm{mV}$$), what has occurred?

Accepted Answer

Hyperpolarization

Question 19

Which of the following is a key characteristic of graded potentials?

Accepted Answer

They vary in magnitude depending on the strength of the stimulus.

Chapter 2: Communication Within the Nervous System – Biological Psychology Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard