ABEM ABEM Anatomy & Neurophysiology

Question 1

Which ion channel is primarily responsible for the upstroke of a nerve action potential?

Accepted Answer

Voltage-gated sodium channels

Answer

Voltage-gated sodium channels open rapidly in response to membrane depolarization, driving the fast upstroke of the action potential.

Question 2

The anterior interosseous nerve is a branch of which major nerve?

Accepted Answer

Median nerve

Answer

The anterior interosseous nerve arises from the median nerve in the proximal forearm and supplies the deep flexor compartment.

Question 3

What is the resting membrane potential of a typical mammalian motor neuron?

Accepted Answer

-70 mV

Answer

The resting membrane potential of most mammalian neurons is approximately -70 mV, maintained by the Na+/K+ ATPase pump.

Question 4

Which structure forms the myelin sheath in the peripheral nervous system?

Accepted Answer

Schwann cells

Answer

Schwann cells wrap around peripheral nerve axons to form the myelin sheath, enabling saltatory conduction.

Question 5

The dorsal interossei muscles of the hand are innervated by which nerve?

Accepted Answer

Ulnar nerve

Answer

The dorsal interossei are innervated by the deep branch of the ulnar nerve and function to abduct the fingers.

(ABEM) American Board of Electrodiagnostic Medicine Practice Test