Human Anatomy and Physiology - N. I. Fedyukovich 2003

Sensory Organs
The Organ of Taste

The surface of the Tongue, the posterior pharyngeal wall, and the soft palate contain receptors that detect sweet, salty, bitter, and sour tastes. These receptors are known as taste buds. The latter are primarily located in the circumvallate, foliate, and fungiform papillae of the tongue, as well as in the mucous membrane of the palate, fauces, and epiglottis.

Each taste bud consists of taste and supporting Cells. At the apex of the taste bud, There is a taste pore that opens onto the surface of the mucous membrane. Taste buds consist of supporting and receptor taste cells; the latter have microvilli 2 μm in length and about 0.2 μm in diameter.

Microvilli extend to the surface of the tongue through taste pores. Thanks to these microvilli, the perception of taste stimuli occurs. Taste receptors are unevenly distributed across the surface of the tongue (Fig. 151). Thus, the sensation of bitterness is linked to The stimulation of the Base of the tongue, while the sensations of saltiness and sweetness are triggered by the stimulation of the tip, margins, and base of the tongue. Sour taste is most commonly due to the stimulation of receptors located in the basal and middle PARTS OF THE lateral surface of the tongue. Taste zones can overlap; for example, bitter receptors may be located in the zone where sweet taste is perceived.

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Fig. 151. Papillae of the tongue. Taste Zones of the tongue:

A — papillae of the tongue; a — general view; b — fungiform papilla; c — filiform papilla; d — foliate papilla; e — circumvallate papilla (1 — fungiform papillae; 2 — filiform papillae; 3 — foliate papillae; 4 — circumvallate papillae); B — taste zones of the tongue

When food is present in the Oral Cavity, a complex of stimuli arises. These travel along nerve fibers branched around one or more receptor cells, are converted from a stimulus into excitation, and are transmitted to the cortical area of the Brain's gustatory analyzer. The cortical area of the gustatory analyzer is located in the region of the uncus and the parahippocampal gyrus of the temporal lobe of the Cerebral Cortex.