Directional Terms
CNS parts
Muscle Action
PNS parts
100

toward the head or from a high position

Superior

100

consists of the medulla, pons, and midbrain, is continuous with the spinal cord and lies inferiorly to the cerebral hemispheres

Brainstem

100

bringing structures together

Adduct

100

12 pairs of these

Cranial nerves

200

toward the feet or from a low position

Inferior

200

lies just posterior to the pons, is involved in the coordination and precision of fine motor movement.

Cerebellum

200

moving structures apart

Abduct

200

31 pairs of these 

spinal nerves

300

toward the belly

Anterior

300

acts as a relay station for sensory fibers

Thalamus

300

bending of a joint

Flexion

300

lubricate speech structures like the oral cavity and vocal cords

Salivary Glands

400

toward the back

Posterior

400

regulates various body functions (e.g., body temperature)

Hypothalamus

400

straightening of a joint

Extension

400

regulation of organs and glands

Parasympathetic functions

500

toward the midline of the body

Medial

500

regulates genital development, the sleep–wake cycle, and optic reflexes.

Epithalamus

500

Lying with ventral surface up

Supine

500

have specialized organs devoted to them, and include vision, hearing, taste, and smell.

special sensory experiences