THE ORGANS OF SPECIAL SENSE 



593 



The Organ of Taste 



The organ of taste consists of the so-called taste buds of the lingual 

 mucosa. These have been mentioned in connection with the papillae 

 of the tongue (page 231) and under sensory end-organs (p. 438). 



The taste buds are found in the side walls of the circumvallate 

 papillai (page 231), of some few of the fungiform papilkc, in the 

 mucosa of the posterior surface of the epiglottis, and especially in 

 folds (fohate papillae) which occur along the postero-lateral margin 

 of the tongue. 



The taste bud (Fig. 392) is an ovoid epithehal structure embedded 

 in the epithehum and connected with the surface by means of a min- 

 ute canal, the gustatory canal (Fig. 

 392, a), the outer and inner ends of 

 which are known, respectively, as the 

 outer and inner taste pores. 



Each taste bud consists of two 

 kinds of cells, neuro-epithelial cells or 

 gustatory cells and sustentacular cells 

 (Fig. 392). The gustatory cells are 

 long, delicate, spindle-shaped cells 

 which occupy the centre of the taste 

 bud, each ending externallv in a cilium- 

 like process, which usually projects 

 through the inner pore. The inner end 

 of the cell tapers down to a fine process, 

 which may be single or branched. The 

 sustentacular cells are long, slender 

 cells which form a shell several cells thick around the gustatory 

 cells. Sensory terminals of the glosso-pharyngeal nerves (Fig. 

 392, b) end within the taste buds in a network of varicose fibres — 

 intrageminal fibres. Other sensory terminals of the same nerve end 

 freely in the epithelium between the taste buds. These are finer 

 and smoother than the intrageminal fibres and are known as inter- 

 geminal fibres (Fig. 392). 



Fig. 392. — Taste-bud from 

 Side Wall of Circumvallate Pa- 

 pilla. (Merkel-Henle.) a, Taste- 

 pore; h, nerve fibres, some of 

 which enter the taste-bud — in- 

 trageminal fibres; while others 

 end freely in the surrounding 

 epithelium — intergeminal fibres. 



TECHNIC 



(i) The general structure of the taste buds is shown in the sections of tongue 

 (technic, p. 232). 



(2) For the studj' of the nerve terminals the method of Golgi should be used 

 (page 36). 

 38 



