FUNCTIONAL PARTS OF THE NERVOUS SYSTEM 



75 



FIG. 41 



temporal lobe with the posterior body. They seem to be unconnected 

 with the afferent fibers of the cord. 



It is possible that the anterior corpora are concerned in regulating the 

 movements of the body and of the eyes under the influence of vision. 

 The posterior pair have probably some sort of control over the muscular 

 movements of producing the voice. 

 On removing them from dogs and 

 apes the voice is lost, and when 

 one of them in man is diseased the 

 hearing of the contralateral ear 

 is lessened. Removal of the four 

 causes the interesting " forced 

 movements" in which the animal 

 on attempting to move makes 

 various sorts of circular motions 

 or rolls over. This indicates that 

 the function of equilibrium is in- 

 volved, and we know that their 

 connection with the cerebellum is 

 intimate. 



TheHypophysisCerebri (pineal 

 body) is discussed under the In- 

 ternal Secretions on page 218. 



as its 

 imply, 



is primarily a bridge connecting 

 by its gray and its white nueral 

 structures the different parts of 

 the nervous system, coordinating 

 the sensory and the motor tracts, 

 and furthering generally the asso- 

 ciation of impulses of many sorts. 

 The sense-organs of the skin and 

 mucous membranes send impulses 

 into the pons, as do also those 

 of the muscles and joints. It 

 seems especially to connect the 

 cortex of the hemisphere with that 

 of the opposite side of the cere- 

 bellum, its middle portions lat- 

 erally being the great middle 

 peduncles of the cerebellum. With 

 the equilibrium of the head (and thereby of the body) it has much to do 

 by its connection with the vestibular branch of the auditory nerve and 

 with the cerebellum. The muscular movements of that part of the ali- 

 mentary canal within and above the pharynx appear to be controlled 

 via the fifth nerve partly within the pons. Efferent (muscular and 



The Pons. The pons, 

 name and position both 



Ventral (anterior) aspect of the medulla and 

 of the parts above it: 1, infundibulum; 2, tuber 

 cinereum; 3, corpora albicantia; 4, cerebral 

 peduncle; 5, annular tubercle; 6, place of origin 

 of the middle cerebellar peduncle; 7, anterior 

 pyramids of the bulb; 8, decussation of these 

 pyramids; 9, olivary bodies; 10, restiform bodies; 

 11, arciform fibers; 12, upper end of the spinal 

 cord; 13, denticulate ligament; 14, the cord's 

 dura mater; 15, optic tracts; 16, chiasma; 17, 

 motor oculi nerve; 18, pathetic; 19, trigeminal; 

 20, abducens; 21, facial; 22, auditory, etc.; 23, 

 nerve of Wrisberg; 24, glossopharyngeal; 25, 

 pneumogastric; 26, spinal accessory; 27, hypo- 

 glossal; 28, 29, 30, spinal nerves. (Sappey.) 



