462 - Multicellular Animals, Especially Man 



Table 25-1— The Cranial Nerves of Man 



Numbei 



1 



II 

 III 



IV 



V 



VI 



VII 



VIII 



IX 



X 



XI 

 XII 



Name 

 Olfactory 



Optic 

 Oculomotor 



Trochlear 

 Trigeminal 

 Abducens 

 Facial 



Auditory 

 Vestibular 



Glossopharyngeal 



Vagus 



Spinal accessory 

 Hypoglossal 



Origin of the Sensory Fibers 



Olfactory mucous mem- 

 brane of nose (smell) 

 Retina of the eye (vision) 

 Proprioceptors in eye mus- 

 cles (muscle sense) 



Eve muscles (muscle sense) 



Teeth. Skin of face 



Eye muscles (muscle sense) 



Taste buds of anterior two- 

 thirds of tongue 



Cochlea (hearing) 



Semicircular canals, sac- 

 culus, utriculus (senses of 

 movement, balance, rota- 

 tion) 



Mucous membrane of 

 pharynx (swallowing re- 

 flex). Taste buds of 

 posterior one-third of 

 tongue 



Lungs (reflex control of 

 respiratory rhythm). Mu- 

 cous membrane of larynx. 

 Arch of aorta (control of 

 blood pressure). Stomach 

 (hunger) 



Muscles of shoulder (muscle 

 sense) 



Tongue muscles (muscle 

 sense) 



Termination of the Motor Fibers 



None 



None 



Muscles that move the eye 



(with IV and VI). Muscles of 



accommodation (lens). Iris 



(constriction of pupil) 

 Muscles that move the eye 



(with III and VI) 

 Some of the muscles used in 



chewing 

 Muscles that move the eye 



(with III and IV) 

 Muscles of the face. Salivary 



glands (submaxillary and 



sublingual) 

 None 

 None 



Muscles of pharynx (swallow- 

 ing). Salivary glands (parotid) 



Heart (inhibition). Stomach, 

 small intestine (augmentation 

 of peristalsis). Muscles ot 

 larynx (speech). Muscles ot 

 esophagus (swallowing). Gas- 

 tric glands (secretory) 



Muscles ol shoulder girdle 

 (shoulder movements) 



Muscles in tongue (tongue 

 movements) 



animal involves at least one sensory neuron jerk" and other proprioceptive reflexes from 



and one motor neuron, to which impulses the tendons and muscles. Most responses in 



are passed directly in the gray matter of the the intact animal involve a number of asso- 



same segment of the spinal cord (Fig. 25-14). ciation neurons; and in the case ol supra- 



However, such two-neuron arcs play no essen- segmental reflexes, which involve the relay- 



tial role in behavior, except possibly in the ing of impulses through a higher center of 



case of very simple reflexes like the "knee the brain, the number of association neu- 



