The Cranial Nerves

There are 12 cranial nerves and they originate from the brain and upper spinal cord and they innervate the special sense organs in the head (eye, ear, nose, and taste buds), the skin over the face and neck, and muscles that permit us to speak, eat, and produce facial expressions. These cranial nerves also provide parasympathetic innervation to the eye and glands in the head and neck and via the X cranial nerve, the vagus, to the organs of the cardiovascular system, pulmonary system, gastrointestinal system, and urogenital system.

HINT: When you study the cranial nerves, first learn the functions of the following “easy” cranial nerves: special sensory, I (smell), II (vision), and VIII (hearing and balance); eye movements, III, IV, and VI (LR6SO4); pure motor functions of XI (shrug shoulders and turn neck) and XII (tongue movements), parasympathetic functions: III, VII, IX, and X; Figure 5.11. Then learn the more difficult mixed ones: V, VII, IX, and X.