264 ANATOMY AND PHYSIOLOGY FOR NURSES 



circumference of the tympanum. In structure it is partly 

 fibrocartilaginous and partly bony. It is broad and ex- 

 panded at its pharyngeal extremity, and narrow and com- 

 pressed at the tympanum. 



The nerve supply is mainly from the auditory nerve. 



The internal ear, or labyrinth, is the essential 

 part of the organ of hearing. It consists of three parts 

 the vestibule, semicircular canals, and cochlea. It receives 

 the ultimate distribution of the auditory nerve. It is 

 connected with the middle ear by two openings, the 

 fenestra rotunda and the fenestra ovalis. 



(The nurse will do well to devote some time to the 

 study of these Organs, for she will often be called upon to 

 care for patients in whom these important parts are dis- 

 eased.) 



THE ORGANS OF TASTE 



The chief organ of taste is the tongue, and yet the palate 

 and lips participate in receiving the impressions made 

 by substances taken into the mouth. These impressions 

 are conveyed to the brain by the nerves, and thus a per- 

 ception of the quality of the taste or impression on the 

 tongue is effected. 



The tongue is a double organ, composed chiefly of 

 muscular fibers, which run in almost every direction. 

 The two sides are absolutely distinct, so that sometimes, 

 as in paralysis, one side is affected while the function of 

 the other remains unimpaired. It possesses great versa- 

 tility of motion, and can be molded into a variety of shapes. 

 The tongue is an auxiliary to other organs in articulation, 

 mastication, and deglutition. 



This organ is abundantly supplied with blood-vessels, 

 a large artery being sent to each side of it. It is also 

 well furnished with nerves, receiving nervous filaments 

 from the fifth, ninth, and twelfth pairs of nerves. The 

 branch of the fifth, formerly called the gustatory, from its 



