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

$$E_{ion} = 62 \mathrm{mV} \times \log \left( \frac{[ion]_{out}}{[ion]_{in}} \right)$$

Q: Which formula accounts for the equilibrium potential of the entire neuronal membrane, considering multiple ions and their permeabilities?

$$V_m = 58 \mathrm{mV} \times \log \left( \frac{P_{K^+}[K^+]_{out} + P_{Na^+}[Na^+]_{out} + P_{Cl^-}[Cl^-]_{in}}{P_{K^+}[K^+]_{in} + P_{Na^+}[Na^+]_{in} + P_{Cl^-}[Cl^-]_{out}} \right)$$

Question 1

Which of the following best describes the primary function of sensory neurons in the nervous system?

Accepted Answer

They collect information from the environment and relay it to the central nervous system.

Question 2

A patient has damage to the Schwann cells in their peripheral nervous system. Which of the following consequences is most likely?

Accepted Answer

Slower conduction of action potentials along peripheral axons due to loss of myelin.

Question 3

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

Accepted Answer

$$E_{ion} = 62 \mathrm{mV} 	imes \log \left( \frac{[ion]_{out}}{[ion]_{in}} ight)$$

Question 4

During the startle response in the cockroach Periplaneta americana, which sequence correctly describes the flow of information?

Accepted Answer

Sensory neuron → Giant interneuron → Motor neuron → Muscle

Question 5

Which glial cell type is responsible for immune defense and phagocytosis in the central nervous system?

Accepted Answer

Microglial cells

Question 6

What is the main role of the Na+/K+ ATPase pump in maintaining the resting membrane potential?

Accepted Answer

It pumps 3 Na+ ions out and 2 K+ ions in, creating a net negative charge inside the cell.

Question 7

Which of the following best explains why action potentials propagate undiminished along an axon?

Accepted Answer

Voltage-gated Na+ and K+ channels regenerate the action potential at each segment of the axon.

Question 8

Which formula accounts for the equilibrium potential of the entire neuronal membrane, considering multiple ions and their permeabilities?

Accepted Answer

$$V_m = 58 \mathrm{mV} 	imes \log \left( \frac{P_{K^+}[K^+]_{out} + P_{Na^+}[Na^+]_{out} + P_{Cl^-}[Cl^-]_{in}}{P_{K^+}[K^+]_{in} + P_{Na^+}[Na^+]_{in} + P_{Cl^-}[Cl^-]_{out}} ight)$$

Question 9

Which of the following is a direct consequence of the absolute refractory period in neurons?

Accepted Answer

A second action potential cannot be initiated, regardless of stimulus strength.

Question 10

A neuron has the following ion concentrations: $$[K^+]_{in} = 140 \mathrm{mM}$$, $$[K^+]_{out} = 5 \mathrm{mM}. $$Using the Nernst equation $$E_{K^+} = 62 \mathrm{mV} 	imes \log \left( \frac{[K^+]_{out}}{[K^+]_{in}} ight)$$, what is the equilibrium potential for potassium?

Accepted Answer

$$E_{K^+} \approx -89 \mathrm{mV}$$

Question 11

Which structural feature of a neuron is primarily responsible for transmitting electrical signals over long distances?

Accepted Answer

Axon

Question 12

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

Accepted Answer

They connect capillaries to neurons and provide metabolic support.

Question 13

During the rising phase of an action potential, which ion movement is primarily responsible for depolarization?

Accepted Answer

Inward movement of Na+

Question 14

Which of the following is NOT a characteristic of neuronal communication?

Accepted Answer

Relies solely on chemical diffusion without electrical signaling

Question 15

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

Accepted Answer

Myelin acts as an electrical insulator, allowing action potentials to jump between nodes of Ranvier (saltatory conduction).

Question 16

Which of the following best describes the function of synaptic vesicles in the presynaptic terminal?

Accepted Answer

They store neurotransmitters that are released into the synaptic cleft during synaptic transmission.

Question 17

A researcher observes that a neuron is hyperpolarized and less likely to fire an action potential. Which phase of the action potential is most likely occurring?

Accepted Answer

Relative refractory period

Question 18

Which of the following best describes the role of interneurons in the nervous system?

Accepted Answer

They connect the peripheral nervous system (PNS) to the central nervous system (CNS).

Question 19

Which of the following is a direct effect of the interaction between the nervous system and the endocrine system?

Accepted Answer

Long-term regulation of body functions such as growth and metabolism

Nervous System Structure and Function: Neurons, Synapses, and Membrane Potentials

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