Skieresz-Szewczyk Kinga, Jackowiak Hanna, Ratajczak Marlena
Department of Histology and Animal Embryology, The Poznan University of Life Sciences, Wojska Polskiego 71C, 60-625 Poznań, Poland.
Department of Histology and Animal Embryology, The Poznan University of Life Sciences, Wojska Polskiego 71C, 60-625 Poznań, Poland.
Micron. 2014 Dec;67:117-124. doi: 10.1016/j.micron.2014.07.004. Epub 2014 Jul 27.
The previous histological studies of the lingual mucosa in birds characterized two types of keratinized epithelium, i.e. orthokeratinized and parakeratinized. These epithelia are composed of three layers: basal, intermediate and keratinized. The present study showed detailed ultrastructural features of cells in particular layers of two types of keratinized epithelia on the tongue in the domestic duck and defined structural differences. TEM observations showed a gradual reduction in cell organelles in the following layers, at increasing amounts of keratin fibers. The characteristic feature of the ortho- and parakeratinized epithelium is the presence of sub-layers in the intermediate layer, i.e. the upper and lower part, which results from the different shape of cell nuclei and dye affinity of the cytoplasm. The keratinized layer of ortho- and parakeratinized epithelium is built of two types of cells such as electron dark and light cells, which undergo exfoliation. The basic difference between the keratinized epithelia is the presence of flattened cell nuclei in the keratinized layer of the parakeratinized epithelium. The differentiating feature is also an arrangement of keratin fibers in the cell cytoplasm of the keratinized layer. The analysis of the thickness of the epithelium and the keratinized layer, indicated differences between keratinized epithelia, which result from two variants of performing protective functions, either through a thick keratinized layer or by a higher epithelium. Differences in the ultrastructure of the ortho- and parakeratinized epithelium are associated with mechanical functions of the epithelium resulting from different forces acting on the tongue during feeding activities.
先前对鸟类舌黏膜的组织学研究表明存在两种角化上皮，即正角化上皮和不全角化上皮。这些上皮由三层组成：基底层、中间层和角化层。本研究展示了家鸭舌部两种角化上皮特定层细胞的详细超微结构特征，并明确了结构差异。透射电镜观察显示，随着角蛋白纤维数量增加，各层细胞细胞器逐渐减少。正角化和不全角化上皮的特征是中间层存在亚层，即上部和下部，这是由细胞核形状和细胞质染色亲和力不同导致的。正角化和不全角化上皮的角化层由两种细胞组成，即电子密度高的细胞和电子密度低的细胞，这些细胞会发生脱落。角化上皮之间的基本差异在于不全角化上皮角化层中存在扁平细胞核。其区别特征还在于角化层细胞质中角蛋白纤维的排列。上皮厚度和角化层厚度分析表明，角化上皮之间存在差异，这是由于通过厚角化层或较高上皮层执行保护功能的两种变体所致。正角化和不全角化上皮超微结构的差异与进食活动期间作用于舌部的不同力量所导致的上皮机械功能有关。
