Structure and Growth of the Utricular Macula in the Inner Ear of the Slider Turtle Trachemys scripta
| Autor: | Jørgen Mørup Jørgensen, Jens R. Nyengaard, Stig Å. Severinsen |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2003 |
| Předmět: |
Slider turtle
Utricular macula Stereology Stereovilli Biology behavioral disciplines and activities Models Biological Article mental disorders Hair Cells Auditory medicine Animals Inner ear Saccule and Utricle Vestibular Hair Cell Age Factors Anatomy Kinocilium Sensory Systems Turtles medicine.anatomical_structure Trachemys scripta Otorhinolaryngology embryonic structures Microscopy Electron Scanning sense organs Cell Division |
| Popis: | In general, postembryonic production of inner ear vestibular hair cells (HCs) is believed to occur in all nonmammalian vertebrates. However, no study on this topic has been published on reptiles and, consequently, it is not known whether this also applies to these vertebrates. Therefore, the present study applied stereological methods in order to estimate the total number of HCs in turtles of varying sizes. The findings are that in prehatchlings the utricular macula (UM) contains approximately 4000 HCs as compared to approximately 5000 in juveniles, approximately 8000 in medium-sized turtles, and approximately 12,000 in large, sexually mature turtles. Scanning electron microscopy (SEM) reveals that presumably newly generated HCs with small surface areas and thin stereovilli are found in all regions of the UM. Furthermore, it reveals that utricular HCs can be classified as belonging to a specific region from the morphology of their apical structure. Striolar HCs have a large free oval-to-ovoid surface, a hair bundle with numerous stereovilli, and a short kinocilium. Rampary and cotillary HCs have smaller and slimmer free surfaces, comparatively fewer stereovilli, but much longer kinocilia. In conclusion, the current study demonstrates that postembryonic production of HCs does occur in reptiles and thereby supports the general view that this is a common trait in all nonmammalian vertebrates. |
| Databáze: | OpenAIRE |
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