THE SENSE OF TASTE. 



595 



FIG, 



are regarded as their peripheral end-organs and known as taste-buds 

 or taste-beakers. Each bud is ovoid in shape (Fig. 276). Its base 

 rests on the tunica propria ; its apex comes up to the epithelium, where 

 it presents a narrow funnel-shaped opening, the taste-pore. The wall 

 of the bud is composed of elongated curved epithelium. The 

 interior contains narrow spindle-shaped neuro-epithelial cells pro- 

 vided at their outer extremity with stiff hair-like 

 filaments which project into the taste-pore. 



The neuro-epithelial cells are in physiologic 

 relation with the nerves of taste. The terminal 

 branches, after entering the bud at its base, 

 develop fine tufts which come into contact with 

 the cells. That the taste-buds are connected with 

 the nerves of taste is rendered probable from the 

 fact of their degeneration after division of the 

 nerves. 



The Taste Area. The taste area, though 

 confined for the most part to the tongue, extends 

 itself in different individuals to the mucous mem- 

 brane of the hard palate, to the anterior sur- 

 face of the soft palate, to the uvula, the anterior 

 and posterior half arches, the tonsils, the posterior 

 wall of the pharynx, and the epiglottis. 



The Taste Sensations. The sensations 

 which arise in consequence of impressions made 

 by different substances on the peripheral appara- 

 tus of this area are in so many instances com- 

 binations of taste, touch, temperature, and smell 

 that they are extremely difficult of classification. 

 Nevertheless four primary tastes can be recog- 

 nized: viz., bitter, sweet, acid orsour,salt or saline. 

 Though the contact of any bitter, sweet, acid, 

 or salt substance with any part of the tongue 

 will, if the substance be present in sufficient 

 quantity or concentration, develop a corresponding 

 sensation, some regions of the tongue are more sensitive and respon- 

 sive than others. Thus, the posterior portion is more sensitive to 

 bitter substances than the anterior; the reverse is true for sweet 

 substances and perhaps for acids and salines. 



The intensity of the resulting sensation in any given instance 

 will depend on the degree of concentration of the substance, while 

 its massiveness will depend on the area affected. 



276. TASTE- 

 BUD FROM CIR- 

 CUMVALLATE 

 PAPILLA OF A 

 CHILD. The 

 oval structure is 

 limited to the 

 epithelium (e) 

 lining the fur- 

 row, encroach- 

 ing slightly 

 upon the adja- 

 cent connective 

 tissue (/) ; o, 

 taste-pore 

 through which 

 the taste - cells 

 communicate 

 with the mucous 

 surface. (After 

 Piersol.} 



