EDT Neuroanatomy & Physiology 3

Question 1

Which layer of a peripheral nerve surrounds individual axons?

Accepted Answer

Endoneurium

Answer

The endoneurium is the innermost connective tissue layer that directly ensheathes each individual nerve fiber.

Question 2

The H-reflex is the electrophysiological analogue of which clinical reflex?

Accepted Answer

Ankle (Achilles) tendon reflex

Answer

The H-reflex bypasses the muscle spindle and electrically activates Ia afferents, mimicking the ankle tendon (Achilles) reflex arc.

Question 3

What is the function of Ia afferent fibers from muscle spindles?

Accepted Answer

Signal dynamic and static muscle stretch to the spinal cord

Answer

Ia afferents from primary endings of muscle spindles signal both the dynamic (velocity) and static (length) components of muscle stretch.

Question 4

In a demyelinating neuropathy, which electrodiagnostic parameter is most characteristically prolonged?

Accepted Answer

Distal motor latency

Answer

Loss of myelin slows conduction velocity and prolongs distal motor latency, the hallmark of a demyelinating process on NCS.

Question 5

Which spinal cord levels form the lumbosacral plexus roots that contribute to the sciatic nerve?

Accepted Answer

L4–S3

Answer

The sciatic nerve is formed from anterior rami of L4 through S3, making it the largest nerve in the body.

(EDT) Electrodiagnostic Technician Certification Practice Test