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Two generations of the tongue and gustatory organs in the development of Hynobius dunni Tago
Author(s) -
Żuwała K.,
Kato S.,
Jakubowski M.
Publication year - 2002
Publication title -
journal of anatomy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 118
eISSN - 1469-7580
pISSN - 0021-8782
DOI - 10.1046/j.1469-7580.2002.00076.x
Subject(s) - tongue , taste , anatomy , sensory system , dysgeusia , biology , metamorphosis , larva , medicine , pathology , neuroscience , ecology , pharmacology , adverse effect
In the development of Hynobius dunni there are two consecutive generations of the tongue and two generations of gustatory organs (taste buds and taste disks). The anlage of the developing secondary tongue appears just in front of the free ending of the primary tongue beginning at the larval developmental stage 62. From stage 67, a gradual reduction in the anterior part of the gill skeleton that supports the primary tongue occurs as the developing secondary tongue replaces the primary one. The lining of the entire oropharyngeal cavity of larvae contains only gustatory organs of the taste bud (TB) type. In younger larvae, the sensory area of a TB has a diameter of between 10 and 13 µm, while in older larvae, TBs reach 16–18 µm in diameter. After metamorphosis, some gustatory organs in the secondary tongue with a sensory area of 26–36 µm in diameter appear. In older animals they may reach as much as 56–71 µm. In other regions of the oropharyngeal epithelium than the tongue, these organs have an ellipsoid shape with a major axis of about 50 µm. On the basis of the cytomorphological criteria established previously, these organs were designated as taste disks. Thus, the presence of two generations of gustatory organs is characteristic of some urodeles, as well as frogs.