Q: Which equation correctly represents the Nernst equation for calculating the equilibrium potential of an ion?

$$E = \frac{RT}{zF} \ln \left( \frac{[\text{ion}]_{\text{outside}}}{[\text{ion}]_{\text{inside}}} \right)$$

Question 1

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

Accepted Answer

It increases the speed of action potential propagation by insulating the axon.

Question 2

A patient presents with loss of sensation in the lateral forearm and weakness in elbow flexion. Which nerve of the brachial plexus is most likely affected?

Accepted Answer

Musculocutaneous nerve

Question 3

During the generation of an action potential, which event occurs immediately after the membrane potential reaches threshold?

Accepted Answer

Voltage-gated sodium channels open, causing rapid depolarization.

Question 4

Which neurotransmitter is primarily released by postganglionic sympathetic fibers?

Accepted Answer

Norepinephrine

Question 5

A lesion in the precentral gyrus would most likely result in which of the following deficits?

Accepted Answer

Loss of voluntary motor control on the contralateral side of the body

Question 6

Which equation correctly represents the Nernst equation for calculating the equilibrium potential of an ion?

Accepted Answer

$$E = \frac{RT}{zF} \ln \left( \frac{[	ext{ion}]_{	ext{outside}}}{[	ext{ion}]_{	ext{inside}}} ight)$$

Question 7

Which of the following best explains why the absolute refractory period prevents a second action potential from occurring?

Accepted Answer

Voltage-gated sodium channels are inactivated and cannot reopen immediately.

Question 8

A patient with damage to the Broca's area would most likely experience which of the following symptoms?

Accepted Answer

Difficulty producing spoken language

Question 9

Which of the following is a function of the reticular formation in the brainstem?

Accepted Answer

Regulation of arousal and consciousness

Question 10

Which cranial nerve is responsible for the majority of parasympathetic output to thoracic and abdominal organs?

Accepted Answer

Vagus nerve (CN X)

Question 11

A patient is unable to dorsiflex the foot and has numbness over the lateral leg. Which nerve is most likely injured?

Accepted Answer

Common fibular (peroneal) nerve

Question 12

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

Accepted Answer

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

Question 13

Which neurotransmitter is released at the neuromuscular junction to stimulate skeletal muscle contraction?

Accepted Answer

Acetylcholine

Question 14

Which of the following is true regarding the difference between EPSP and IPSP at a synapse?

Accepted Answer

EPSP depolarizes the postsynaptic membrane, while IPSP hyperpolarizes it.

Question 15

Which structure is responsible for producing cerebrospinal fluid (CSF) in the brain?

Accepted Answer

Choroid plexus

Question 16

A patient with a lesion in the posterior (dorsal) horn of the spinal cord would most likely experience which deficit?

Accepted Answer

Loss of sensory input from the affected region

Question 17

Which of the following best describes the function of the sodium-potassium pump in neurons?

Accepted Answer

It maintains the resting membrane potential by moving 3 Na	extsuperscript{+} out and 2 K	extsuperscript{+} in per ATP hydrolyzed.

Question 18

Which of the following is a real-life example of a monosynaptic reflex arc?

Accepted Answer

Patellar (knee-jerk) reflex

Question 19

Which equation best represents the Goldman-Hodgkin-Katz equation for membrane potential?

Accepted Answer

$$V_m = \frac{RT}{F} \ln \left( \frac{P_{K^+}[K^+]_{	ext{out}} + P_{Na^+}[Na^+]_{	ext{out}} + P_{Cl^-}[Cl^-]_{	ext{in}}}{P_{K^+}[K^+]_{	ext{in}} + P_{Na^+}[Na^+]_{	ext{in}} + P_{Cl^-}[Cl^-]_{	ext{out}}} ight)$$

Question 20

Which of the following best describes the difference between chemical and electrical synapses?

Accepted Answer

Chemical synapses use neurotransmitters to transmit signals, while electrical synapses use gap junctions for direct ion flow.

Organization of the Nervous System, Neurons, and Neurotransmitters

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