1124 



THE DIGESTIVE SYSTEM 



LINGUA. 



The tongue is a large mobile mass, which occupies the floor, of the mouth 

 and forms the anterior wall of the oral part of the pharynx (Fig. 889). It is 

 composed chiefly of muscular tissue, and is covered by mucous membrane. 



Whilst the sense of taste resides chiefly in its modified epithelium, the tongue 

 is also an important organ of speech, and, in addition, it assists in the mastica- 



Middle concha 

 Middle meatus of nose 



Inferior meatus 

 of nose 



Superior meatus of nose 



Sphenoidal sinus 

 Inferior concha 



Genioglossus 



Genio-hyoid 



Posterior edge of nasal septum 

 Orifice of auditory 

 tube 



Bursa pharyngea 



Part of the 

 pharyngeal tonsil 



_,, Recess of pharynx 



Torus levatorius 



Salpingo- 

 pharyngeal fold 



Glands in soft 

 palate 

 Giosso- 

 palatine arch 

 _ Supra-tonsillar 

 fossa 



Plica triangularis 

 Palatine tonsil 



Pharyngo-palatine 

 arch 



Epiglottis 



Aryteno- 

 epiglottic fold 



Cricoid cartilage 



Lymph follicle 



Hyoid bone 



PIG. 889. SAGITTAL SECTION THROUGH MOUTH, TONGUE, LARYNX, PHARYNX, AND NASAL CAVITY. 

 The section was slightly oblique, and the posterior edge of the nasal septum has been preserved. 



The specimen is viewed slightly from below, hence the apparently low position of the inferior 



concha. 



tion and deglutition of the food functions which it is well fitted to perform 

 owing to its muscular structure and great mobility. In length it measures 

 about three and a half inches (9 cms.), when at rest, but both its length 

 and width are constantly varying with every change in the condition of the 

 organ, an increase in length being always accompanied by a diminution in width 

 and vice versa. 



In describing the tongue we distinguish the following parts : the corpus lingua 

 (body), made up chiefly of striped muscle, and forming the mass of the organ ; thf 

 dorsum linguae (Fig. 890), which looks towards the palate and pharynx, and is free 



