Q: If the extracellular concentration of $$Na^+ is 145 mM $$and the intracellular concentration is 15 mM, what is the equilibrium potential for $$Na^+ at 37$$°C? (Use the Nernst equation: $$E_{Na} = \frac{61}{z} \log_{10} \left( \frac{[Na^+]_{out}}{[Na^+]_{in}} \right)$$, where $$z = +1)$$

$$E_{Na} \approx +60 \text{ mV}$$

Question 1

Which of the following best describes the difference between a nerve and a neuron?

Accepted Answer

A nerve is a collection of axons in the peripheral nervous system, while a neuron is a single cell specialized for signal transmission.

Question 2

Which structure is responsible for integrating information from the afferent nervous system and sending a response through the efferent nervous system?

Accepted Answer

Interneuron

Question 3

Which of the following is a synonym for 'action potential' as listed in the study materials?

Accepted Answer

Spike

Question 4

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

Accepted Answer

Oligodendrocyte

Question 5

A patient has damage to the autonomic nervous system. Which of the following effects would most likely be observed?

Accepted Answer

Impaired regulation of cardiac muscle and smooth muscle activity

Question 6

Which equation would you use to calculate the equilibrium potential for potassium ($$K^+) $$across a cell membrane at physiological temperature?

Accepted Answer

$$E_K = \frac{RT}{zF} \ln \left( \frac{[K^+]_{out}}{[K^+]_{in}} \right)$$

Question 7

Which of the following best describes the function of the myelin sheath?

Accepted Answer

It insulates the axon, increasing the speed of action potential conduction.

Question 8

If the extracellular concentration of $$Na^+ is 145 mM $$and the intracellular concentration is 15 mM, what is the equilibrium potential for $$Na^+ at 37$$°C? (Use the Nernst equation: $$E_{Na} = \frac{61}{z} \log_{10} \left( \frac{[Na^+]_{out}}{[Na^+]_{in}} \right)$$, where $$z = +1)$$

Accepted Answer

$$E_{Na} \approx +60 	ext{ mV}$$

Question 9

Which type of membrane channel is primarily responsible for generating a graded potential (GP) in the dendrites and cell body?

Accepted Answer

Chemically regulated (ligand-gated) $$Na^+$$ channel

Question 10

A neuron receives multiple excitatory post-synaptic potentials (EPSPs) at its dendrites. What must occur for an action potential to be generated?

Accepted Answer

The EPSPs must reach the trigger zone with sufficient strength to reach threshold.

Question 11

Which of the following best explains why action potentials are not decremental?

Accepted Answer

Action potentials regenerate at each segment of the axon, maintaining the same strength throughout.

Question 12

Which of the following is a correct sequence for the organization of the nervous system in response to a stimulus?

Accepted Answer

Stimulus → Receptor → Afferent pathway → CNS → Efferent pathway → Effector → Tissue response

Question 13

Which of the following would most likely result from a loss of function in Schwann cells?

Accepted Answer

Decreased myelination in the peripheral nervous system

Question 14

Which term is synonymous with 'cell body' in neuroscience?

Accepted Answer

Soma

Question 15

A patient presents with impaired voluntary movement but normal autonomic function. Which division of the nervous system is most likely affected?

Accepted Answer

Somatic motor division

Question 16

Which of the following best describes the role of the Na+/K+ pump in establishing the resting membrane potential (RMP)?

Accepted Answer

It actively transports $$3 Na^+$$ out and $$2 K^+ in$$, creating an electrochemical gradient.

Question 17

Which of the following would most likely occur if the axon hillock fails to reach threshold?

Accepted Answer

No action potential will be generated.

Question 18

Which of the following is a correct synonym for 'axon terminal'?

Accepted Answer

Synaptic knob

Question 19

Which of the following best describes the difference between continuous and saltatory conduction?

Accepted Answer

Saltatory conduction involves action potentials jumping between nodes of Ranvier in myelinated axons, increasing speed.

Neurophysiology: Organization and Structure of the Nervous System

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