What is the name for a bundle of axons within a nerve?

Correct Answer: A

Rationale: A fascicle (A) is a bundle of axons within a peripheral nerve. Tracts (B) are CNS axon bundles, nerve roots (C) are spinal nerve origins, and epineurium (D) is the nerve’s outer layer. A is correct.

Correct Answer: C

Rationale: Neural signaling, including sensory input, CNS processing, and motor output, occurs in a fraction of a second (milliseconds) due to the speed of action potentials and synaptic transmission.

Correct Answer: D

Rationale: A thick, myelinated axon propagates action potentials fastest due to saltatory conduction (myelin) and lower resistance (thickness). Myelination speeds conduction more than diameter alone.

Correct Answer: C

Rationale: The middle cerebral artery (MCA) is the largest branch of the internal carotid artery, supplying a significant portion of the cerebral cortex (e.g., lateral aspects). The ophthalmic artery is smaller, and the anterior cerebral and striate arteries are not as large.

Correct Answer: C

Rationale: Central cord syndrome (often cervical) damages the central spinal cord, affecting motor (upper limbs > lower) and pain/temperature sensation, while touch sensation (dorsal columns) often remains intact due to its peripheral location.