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

$$E_i = \dfrac{RT}{nF} \ln \left( \dfrac{[i]_{\text{out}}}{[i]_{\text{in}}} \right)$$

Q: If a neuron’s membrane resistance ($$R_m) $$and capacitance ($$C_m) $$are both large, what effect does this have on the membrane time constant ($$\tau) $$and the neuron's response to current?

Large $$\tau$$; slow response to current.

Question 1

Which of the following best describes the primary function of oligodendrocytes and Schwann cells in the nervous system?

Accepted Answer

They myelinate axons, increasing the speed of action potential conduction.

Question 2

A neuron has a resting membrane potential (RMP) of $$-60\ \mathrm{mV}. $$Which ion has an inward driving force at this potential?

Accepted Answer

Sodium ($$\mathrm{Na}^+)$$

Question 3

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

Accepted Answer

$$E_i = \dfrac{RT}{nF} \ln \left( \dfrac{[i]_{	ext{out}}}{[i]_{	ext{in}}} ight)$$

Question 4

Which glial cell type is primarily responsible for regulating the chemical environment and providing structural support in the central nervous system?

Accepted Answer

Astrocytes

Question 5

A neuron integrates thousands of synaptic inputs due to its highly branched dendritic structure. What type of neuron morphology does this describe?

Accepted Answer

Multipolar/pyramidal

Question 6

Which of the following best explains why myelin increases the speed of action potential conduction?

Accepted Answer

Myelin decreases membrane capacitance, reducing the time required to change membrane potential.

Question 7

Which formula represents the weighted average of equilibrium potentials that determines the resting membrane potential ($$V_m) in $$neurons?

Accepted Answer

$$V_m = \dfrac{g$$_{Na}$$E_{Na} + g_K E_K + g_{Cl} E_{Cl}}{g_{Na} + g_K + g_{Cl}}$$

Question 8

If a neuron’s membrane resistance ($$R_m) $$and capacitance ($$C_m) $$are both large, what effect does this have on the membrane time constant ($$	au) $$and the neuron's response to current?

Accepted Answer

Large $$	au$$; slow response to current.

Question 9

Which of the following is TRUE regarding the role of the Na$$^+/K$^+$$ pump in maintaining the resting membrane potential?

Accepted Answer

It maintains the K$$^+$$ gradient, which is essential for the RMP.

Question 10

A patient has a mutation that reduces the function of astrocytes. Which of the following symptoms would MOST likely result?

Accepted Answer

Impaired chemical regulation and structural support in the CNS.

Question 11

Which property of neurons is most directly responsible for their ability to fire action potentials?

Accepted Answer

Excitability

Question 12

If the extracellular concentration of K$$^+$$ increases significantly, what is the expected effect on the equilibrium potential for K$$^+$$ ($$E_K) $$according to the Nernst equation?

Accepted Answer

$$E_K$$ becomes less negative (more positive).

Question 13

Which of the following best describes the role of microglia in the central nervous system?

Accepted Answer

They mediate immune defense and clear cellular debris.

Question 14

A neuron’s dendritic spines are damaged due to a neurodegenerative disease. What is the most likely consequence?

Accepted Answer

Reduced number of synaptic contacts and impaired input integration.

Question 15

Which of the following equations correctly represents Ohm’s Law as applied to neurons?

Accepted Answer

$$V = I 	imes R$$

Question 16

Which of the following statements about the central nervous system (CNS) is CORRECT?

Accepted Answer

The CNS is protected by bone, meninges, cerebrospinal fluid, and the blood-brain barrier.

Question 17

If a neuron’s membrane capacitance ($$C_m) is $$decreased, what is the expected effect on the speed of action potential conduction?

Accepted Answer

Conduction speed increases.

Question 18

Which of the following is a direct consequence of losing the resting membrane potential (RMP) in neurons?

Accepted Answer

Neurons cannot signal, leading to functional loss.

Question 19

A neuron receives a synaptic input that causes a rapid change in membrane potential. Which property of the neuron determines how quickly this change occurs?

Accepted Answer

Membrane time constant ($$	au = R_m 	imes C_m)$$

Neuronal Structure and Electrical Properties: Study Notes for Anatomy & Physiology

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