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There are twelve pairs of these nerves and, except for the first pair, which arises from the cerebrum, they all originate from the brainstem (p. 233).
The first pair of cranial nerves, associated with the sense of smell. Axons from receptor cells carry impulses to the neurons in the olfactory bulbs, which are extensions of the cerebral cortex located just beneath the frontal lobes (p. 234).
The second pair of cranial nerves lead from the eyes to the occipital lobes of the brain and are associated with vision (p. 234).
The third pair of cranial nerves arise from the midbrain and pass into the orbits of the eyes where one component of each nerve connects to voluntary muscles that raise the eyelid and to four of the six muscles that move the eye. A second component supplies involuntary muscles that adjust the amount of light entering the eyes and focuses the lenses (p. 234).
The fourth pair of cranial nerves arise from the midbrain and are the smallest cranial nerves. Each nerve carries motor impulses to a fifth voluntary muscle that moves the eye and is not innervated by the oculomotor nerve (p. 234).
The fifth pair of cranial nerves are the largest and arise from the pons. They are mixed nerves and consists of the ophthalmic division, maxillary division, and the mandibular division (p. 234).
This division of the trigeminal nerve brings sensory impulses to the brain from the surface of the eyes, tear glands, and the skin of the anterior scalp, forehead, and upper eyelids (p. 234).
This division of the trigeminal nerve carries sensory impulses from the upper teeth, upper gum, and upper lip as well as from the mucous lining of the palate and the skin of the face (p. 234).
This division of the trigeminal nerve transmits impulses from behind the ears, the skin of the jaw, the lower teeth, the lower gum, and the lower lip. The motor branches of this division supply the muscles of mastication and certain muscles in the floor of the mouth (p. 234).
The sixth pair of cranial nerves are quite small and originate from the pons near the medulla oblongata. Each nerve enters the orbit of the eye and supplies motor impulses to the remaining muscles that moves the eye (abduction of the eye) (p. 234).
The seventh pair of cranial nerves arise from the lower part of the pons and emerge on the sides of the face. Their sensory branches are associated with taste receptors on the anterior two thirds of the tongue, and some of their motor fibers transmit impulses to the muscles of facial expression. Other motor fibers function in the autonomic nervous system and stimulate tear and salivary glands (p. 234).
The eighth pair of cranial nerves arise from the medulla oblongata and each consists of a vestibular branch and cochlear branch. The vestibular branch fibers are located in ganglia associated with parts of the inner ear responsible for maintaining equilibrium. The impulses from the cochlear branch pass through the pons and medulla oblongata on their way to the temporal lobes, where they are interpreted; formerly known as the acoustic nerve (p. 234).
The ninth pair of cranial nerves are associated with the tongue and pharynx. The sensory fibers carry impulses from the linings of the pharynx, tonsils, and posterior third of the tongue to the brain. Fibers in the motor component innervate muscles of the pharynx that function in swallowing (p. 234).
The tenth pair of cranial nerves originate in the medulla oblongata and extend downward through the neck into the chest and abdomen. Certain somatic motor fibers carry impulses to the larynx that are associated with speech and swallowing. Autonomic motor fibers supply the heart and many smooth muscles and glands in the thorax and abdomen (p. 234).
spinal accessory nerves
The eleventh pair of cranial nerves originate in the medulla oblongata and the spinal cord; thus, they have both cranial and spinal branches. Each cranial branch joins a vagus nerve and carries impulses to muscles of the soft palate, pharynx, and larynx. The spinal branch descends into the neck and supplies motor fibers to the trapezius and sternocleidomastoid muscles (p. 235).
The twelfth pair of cranial nerves arise from the medulla oblongata and pass into the tongue. They carry impulses to muscles that move the tongue in speaking, chewing, and swallowing (p. 235).
Mnemonic for cranial nerves
On Old Olympus' Towering Top, A Finn And German Viewed Some Hops (http://en.wikipedia.org/wiki/List_of_mnemonics_for_the_cranial_nerves).
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