Concerning control of posture:

Correct Answer: A

Rationale: Hopping reaction is midbrain (A, correct), tonic neck is medullary/spinal (not just spinal, B), optical righting is cortical (C, true but less specific), stretch reflex is spinal (not medulla, D). A is correct.

Correct Answer: C

Rationale: The internal carotid artery (C) enters the cranium via the carotid canal, supplying the brain. The common carotid (A) branches into it but doesn’t enter, jugular vein (B) drains blood, and aorta (D) is systemic. C is correct.

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: A

Rationale: Oligodendrocytes provide myelin for axons in the central nervous system (CNS), where tracts are located. Schwann cells myelinate axons in the peripheral nervous system (PNS), astrocytes support neurons, and satellite cells support cell bodies in the PNS.

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.