Anatomical and scanning electron microscopic investigations of the tongue and laryngeal entrance in the long-legged buzzard (Buteo rufinus, cretzschmar, 1829)

This research aimed to examine the morphological features of the tongue and laryngeal entrance of long‐legged buzzard by macroscopic and scanning electron microscopic methods. Two adult buzzards were used as material. The tongue was fairly elongated and terminated in oval shovel‐like apex. Scale‐like projections were localized on the apex and body of tongue. Both lateral sides of lingual body were contained considerably long thread‐like projections. Many orifices of lingual posterior salivary glands were discerned among scale‐like projections in median sulcus of the lingual body. Papillary crest of sharp conical papilla were observed on the between the body and root of the tongue. No conical papillae or other projections were existent on the root of the tongue, but numerous orifices of posterior salivary gland ducts were detected. In addition, orifices of anterior salivary gland ducts were present on the dorsal and lateral surfaces of the lingual body. Numerous conical papillae were observed on the caudal region of glottis and no conical papillae or any similar projection which were bordered the glottic fissure was noted. Anatomy of these organs in the long‐legged buzzard and white tailed eagle which are the member of the same family, Accipitridae, revealed very high similarity. Microsc. Res. Tech. 75:1245–1252, 2012. © 2012 Wiley Periodicals, Inc.     

Morphology of the lingual surface of South American fur seal (Arctocephalus australis) and sea lion (Otaria flavescens)

In this study, we aimed to describe the morphological characteristics of the lingual papillae in two species of Otariidae family by stereomicroscopy and scanning electron microscopy. We used tongues of two South American Otariidae species. The tongues were elongated and terminated in bifid apex and there was no median sulcus on the dorsal lingual surface. The most numerous type of lingual papilla was filiform in the South American fur seal (SASL) and entire dorsal lingual surface was covered by these filiform papillae but the dorsal surface of the tongue of the South American sea lion was covered by numerous polygonal projections, which were different in size. Fungiform papillae were detected in only SASL and they randomly distributed on the lingual apex and body, and some fungiform papillae were collected into twosome or threesome groups on the posterior part of the lingual body. Circumvallate papilla was found in the center of the lingual radix of South American sea lion. Thread‐like conical papillae were common for both species and they located on the lingual radix. We determined that lingual surface morphology was completely different in each species, although they were members of the same family, Otariidae. Microsc. Res. Tech. 78:140–147, 2015. © 2014 Wiley Periodicals, Inc.     

Morphofunctional structure of the lingual papillae in three species of South American Camelids: Alpaca,guanaco, and llama

The aim of this study was to compare the anatomical and functional characteristics of the lingual papilla among the Camelidae. For this purpose, tongues of alpaca, guanaco, and llama were used. Numerous long and thin filiform papillae were located in the median groove and none were detected on the rest of the dorsal surface of the lingual apex in alpaca. Secondary papillae originated from the base of some filiform papillae on the ventral surface of alpaca tongue. The bases of some filiform papillae of the lateral surface of the lingual apex were inserted into conspicuous grooves in guanaco and tips of filiform papillae on the dorsal surface of the lingual body were ended by bifurcated apex. On the dorsal surface of the lingual apex of llama, there were no filiform papillae but there were numerous filiform papillae on both the lateral margins of the ventral surface of the lingual apex. Fungiform papillae were distributed randomly on dorsal lingual surface and ventral margins of the tongues of all camelid species. Lenticular papillae were located on the lingual torus and varied in size and topographical distribution for each species. Circumvallate papillae had irregular surfaces in llama and alpaca, and smooth surface in guanaco. In conclusion, llama and alpaca tongues were more similar to each other, and tongues of all camelid species displayed more similarities to those of Bactrian and dromedary camels in comparison with other herbivores and ruminants. Microsc. Res. Tech. 79:61–71, 2016. © 2015 Wiley Periodicals, Inc.     

The development of the tongue of the domestic goose from 9th to 25th day of incubation as seen by scanning electron microscopy

The general development of the tongue in birds was described by Lillie ( 1908 ) in chicken. Bryk et al. ( 1992 ) also studied the tongue development in chicken and they observed development of the conical papillae of the body. Our study aims to describe the timing of the development of the tongue morphological features in the domestic goose by using SEM methods. The tongue of the domestic goose is characterized by the widest variety of shape of the particular part of the tongue and mechanical papillae. Results indicated that the formation of the apex, body, lingual prominence, and the root of the tongue take place between the 10th and 19th day of incubation. The tongue elongates rapidly between the 16th and 18th day of incubation. Simultaneously, the median groove appears on the body and the lingual prominence and elongates towards the rostral part of the tongue. The conical papillae of the tongue develop gradually. On the body, the conical papillae develop from the caudal part of the body to the rostral part and on the lingual prominence from the median part of the prominence to the lateral part. Hair‐like papillae at the caudal surface of the body of the tongue remain primordial to the end of the incubation. Our studies on the morphogenesis of the tongue in the domestic goose revealed changes in shape of the particular part of the tongue and rapid pace of the formation of mechanical papillae. The tongue is completely develop before hatching and ready to collect food. © Microsc. Res. Tech., 2012. © 2012 Wiley Periodicals, Inc.     

Morphology of the tongue dorsal surface of gilthead seabream (Sparus aurata)

The gilthead seabream is a food fish, one of the most frequently used in aquaculture. In the species of commercial interest, feeding in captivity is very important and this process is strictly related to the morphological characteristics of the oral cavity. The aim of this study is, using the standard procedures for light and scanning electron microscopy, to analyze the morphology of the tongue dorsal surface to show if relationships are present between the tongue morphology and the nutritional habits and choices of this farmed species. The main characteristic of the gilthead seabream oral cavity floor is the presence of an apical pouch, with, probably, a protective role mainly for the apical, free part of the tongue. Three zones, like in other teleosts, an apex, a body and a root, can be clearly distinguished. In the pouch foliate‐like papillae were observed, while the whole tongue is characterized by the presence of two types of papillae, respectively with a fungiform and cylindroid aspect, both randomly distributed throughout the whole dorsal surface of the tongue. Scattered and numerous taste buds, with the typical pear‐onion shape, together with small and numerous taste pores are also present, distributed throughout the tongue surface. Our results demonstrate that in the gilthead seabream important mechanic and sensory roles are carried out by specific anatomical structures. Our anatomical data could give, together with further biochemical and physiological data, an important support with the aim of improving the nutrition of aquaculture species. Microsc. Res. Tech. © 2012 Wiley Periodicals, Inc.     

Morphological structure of rat tongue using light and scanning electron microscopy

The rat is one of the most commonly used animals in biological research and experimental investigations in medicine. The ultrafine structural components of the epithelium differ depending on the anatomy of the animal and the papilla type. Animal adaptation to food types and environmental circumstances may also be linked to morphological diversity. In the current study, seven male Wistar rat tongues were investigated. For scanning electron microscope (SEM), two rat tongues were immersed in a 10% formalin solution and the other two rat tongues were immersed in a 2.5% glutaraldehyde solution. The tongues of three rats were fixed for regular histological evaluation using triple staining. The three primary components of the Wistar rat tongue are the apex, body and root. The apex had a rounded and bifurcated shape. Filiform papillae and gustatory papillae were easily identified on the dorsal side of the tongue. There were three forms of gustatory papillae; fungiform papillae, vallate papillae and foliate papillae. The purpose of this study was to expose the tongue morphology of the Wistar rat species, which is widely used in investigations. Also, we wanted to show that formalin fixation can be utilized for morphological research in SEM. Finally, the Wistar rat tongue was thoroughly investigated and compared to those of other species.     

Descriptive studies on the tongue of two micro‐mammals inhabiting the Egyptian fauna; the Nile grass rat (Arvicanthis niloticus) and the Egyptian long‐eared hedgehog (Hemiechinus auritus)

The current study aimed to describe the anatomical features of the tongues of two micro‐mammals common in the Egyptian fauna; the Nile grass rat (Arvicathis niloticus), and the Egyptian long‐eared hedgehog (Hemiechinus auritus). The tongues of five adult individuals of each species were excised and processed histologically, histochemically, and morphometrically. Statistical analysis comparing the relative tongue length in both species showed that there was a significant difference, which may correlate with the difference in feeding preferences. Grossly, the Nile grass rat has a dorsal lingual prominence with bifurcated apex while, the long‐eared hedgehog has a median slight elevation with rounded apex. Numerous forms of mechanical and gustatory papillae are scattered along the lingual dorsal epithelium. The histochemical detection of keratin by Holland's trichrome stain showed an intense expression in the case of A. niloticus and mild expression in H. auritus. The framework of the tongue (entoglossum) is supported by either a core of cartilage in H. auritus or bone in A. niloticus which incorporated in the lingual root. The lingual glands also showed marked variation, the Nile grass rat exhibit dense populations of mucous‐secreting glands and lesser populations of serous‐secreting glands, the contrary is true in H. auritus. In conclusion, the micro and macro‐anatomical features of the tongues of both species showed adaptive changes to accommodate the feeding lifestyle. Such type of studies using mammals from different phylogenetic traits and almost have different feeding preferences provide answers to many research questions related to tongue evolution among mammalian vertebrates.     

Macroscopic and microscopic analysis of the tongue of the common opossum (Didelphis marsupialis)

We performed a macroscopic and microscopic study of the tongues of common opossums, Didelphis marsupialis, from South America. We studied two males and two females. We collected morphometric data on the tongue with precision calipers. For the light microscopy and scanning electron microscopy analyses, we fixed tissue fragments in 10% formaldehyde and 2.5% glutaraldehyde, respectively. The opossum tongues averaged 5.87 ± 0.20 cm in length, 3.27 ± 0.15 cm in width at the lingual body, and 3.82 ± 0.15 cm in width at the root. The mean thickness of the lingual body was 1.8 ± 0.1 cm, and the thickness of the root was 3.82 ± 0.15 cm. Sharp filiform papillae were scattered across the entire tongue; conical filiform papillae occurred on the lingual body and tongue tip; fungiform papillae were scattered among the filiform papillae on the lingual body and tongue tip; and there were three vallate papillae at the root of the tongue. We found two strands of papillary projections in the tongue root. Despite the low variability observed in the lingual papillae, the morphological data obtained in this study may be related to the opossum's diverse food habits and the extensive geographic distribution of the species throughout America. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

Ultrastructural aspects of Callithrix penicillata lingual papillae

Callithrix penicillata belongs to the family Callitrichidae, Callithrix genus. They are basically insectivorous, but they consume fruits. The mucosa of the tongue is composed of some papillary types, revealing different levels of expertise. The present study attempted to describe the morphological and ultrastructural aspects of the dorsal surface of the C. penicillata, describing the characteristics and distribution of papillae found. Five tongues of C. penicillata (two females and three males), obtained from breeding colonies of CENP-Ananindeua-PA, died from natural causes. The material was fixed partly in a buffer solution paraformaldehyde 10% and partly in modified Karnovsky solution, divided into apex, body, and root, and then the fragments were used in light microscopy and scanning electron microscopy. The average length of the tongue of the females was 22 mm and for males 20.5 mm. Three types of papillae were described: filiform (along all tissue extension with 154 μm of diameter), fungiform (along all tissue extension with 275 μm of diameter), and vallate (just three units in caudal (dorsal) portion with 672 μm of diameter). Data analysis indicates that the distribution and ultrastructural morphology of the C. penicillata lingual papillae are some similar to other primates.     

Scanning electron microscopy of the tongue papillae in the pig (Sus scrofa)

A clear understanding of the role of different papillae in the pig may permit the development of a more palatable diet, thus, better utilizing anatomical structures and morphological characteristics to enhance health and productivity in this domestic species. The study used ten healthy market-size, mixed-breed pigs to properly describe the surface structure of the tongue papillae using standard scanning electron microscopic techniques. Two types of sharp and blunt filiform papillae were identified. Fungiform papillae, located on the lateral side of the tongue, were circular and large with surface taste pores. The majority of oval papillae on the dorsal surface of the tongue contained multidirectional surface grooves and lacked taste pores. The foliate papillae, located principally on the caudal third and lateral part of the tongue, were comprised of four to five leaves and they had additional pseudopapillae. The two vallate papillae, found in the caudal third and dorsum of the tongue, had a well-defined vallum and pseudopapillae on their surface. At the root of the tongue, two types of conical papillae with or without apex were observed. The entire area covered by conical papillae was deeply occupied by lingual tonsils. The lingual tonsils were scattered with varying sized lymph nodules in the propria mucosa of the conical papillae deep to epithelium. Functionally, the filiform and conical papillae appeared to have a mechanical role whereas fungiform, foliate, and vallate papillae apparently perform a gustatory role in the pig. The tonsillar location at the root of the tongue provides an ideal experimental model for immunohistological and immunological studies on the lymphoid tissue in man.     

Morphology of the European sea bass (Dicentrarchus labrax) tongue

The European sea bass, a member of the Moronidae family, is a food fish, considered one of the first models for the intensive breeding in salt water. It has nowadays an important and increasing presence in the international fishing markets. Sea basses are carnivorous, feeding on little fishes and invertebrates. Considering the important role of the tongue during the intraoral transport and the swallowing of food, scarce data are present in literature about its morphology. The aim of this study was to analyze the morphology of the tongue by means of scanning electron and light microscopy. Adult sea basses were obtained from the aquarium of the Sicilian Center of Experimental Ichthyiopathology of the University of Messina. The fishes were anaesthetized with MS 222 and the heads were then quickly removed and processed for the paraffin embedding and SEM processing. Three different tongue regions could be distinguished: an apex, a body, and a root. Scanning electron and light microscopy showed the presence of numerous canine-like teeth, surrounded by taste buds and numerous fungiform and conical papillae. The teeth were curved and their tips were posteriorly oriented. The results confirm, in teleosts too, the fundamental role of the tongue in the mechanics of food ingestion. Moreover, the presence of taste buds demonstrates the interaction of food processing and taste. These data could be a potential source to identify new and better methods of nutrition in the breeding of this fish.     

Morphogenesis of the tongue mucosa in the domestic duck (Anas platyrhynchos f. domestica) during the late embryonic stages

The tongue in domestic duck, as in other Anseriformes, is characterized by wide variety of shape and mechanical papillae and they fulfill different function during food collection. The present work aims to describe morphological features of the tongue as well as the pace formation of the mechanical papillae during embryonic period. The results may allow to answer whether the tongue in duck is ready to fulfill feeding function after hatching. The study revealed that the particular part of the tongue and the conical papillae of the body develop between 10th and 16th day of incubation, from the caudal part of the body into the rostral part of the tongue. The conical papillae of the lingual prominence in the first row are formed from 11th to 16th day and in the second row at the turn of the 15th and 16th day of incubation. These papillae developed symmetrically from the median part of the lingual prominence, to its edges. The lingual comb, which is used during transport of the food particles, is formed between 16th and 19th day. The present study indicated the morphological changes of the particular part of the tongue and the mechanical papillae were varied between the developmental stages. The morphology of the tongue in the domestic duck is fully developed before hatching and ready to collect food by pecking and grazing. However, filter‐feeding mechanism is not still obvious. Microsc. Res. Tech. 77:667–674, 2014. © 2014 Wiley Periodicals, Inc.     

Light and scanning electron microscopic study of lingual papillae in the wolf (Canis lupus)

In this study, it was aimed to perform light microscopy and scanning electron microscopy (SEM) investigation of the tongue and papilla belonging to two wolves. Light microscopy and SEM images of tongues were taken. It was observed that papillae filiformes concentrated in apex of these investigated tongues. In addition to, these papillae were observed in the whole tongues. It was also determined that papillae fungiformes were distributed rarely in between papillae filiformes. Papillae foliatae were placed in the lateral side of tongues. There were two papillae vallatae in the median part of tongues. Papillae vallatae was determined in radix linguae. It was observed that papillae vallatae formed circular extensions in many different dimensions and a hole was present in a circular structure in the center. Papillae conicae were seen on dorsal surface of radix linguae. Papillae foliatae were seen four laminal structure and placed on the each lateral side of tongues. To the best of our knowledge, this is the first study that presents of light microscopy and SEM findings related with the tongues of wolves.     

Gross and microscopic observations on the lingual structure of the Franciscana (Pontoporia blainvillei--Gervais and d'Orbigny, 1844)

In most anatomical studies developed with mammals, the tongue is described as highly differentiated among different species. However, studies on the tongue of aquatic mammals are still limited as compared to those on terrestrial mammals. The aim of this study was to describe the tongue morphology of the Franciscana dolphin (Pontoporia blainvillei) using macroscopic observations, light, and scanning electron microscopy. Microscopically, the dorsal surface was covered by a keratinized stratified epithelium. Salivary gland acini were found on the middle and caudal third of the tongue. The dorsal surface was totally covered by filiform papillae with a connective tissue core and a connective tissue structure round in shape in the middle and caudal regions.     

Macro‐ and microscopic study on the tongue and lingual papillae of Bison bonasus hybrid as an interspecific species (Bos taurus × Bison bonasus)

Nowadays the processes of crossing of different mammalian species are well characterized in light of genetics, and possibility of reproduction. Generally, lack detailed studies on changes in anatomy and histology of internal systems of hybrids. Bison bonasus hybrid is an interspecific species between the bull of European bison (Bison bonasus), and female of domesticated cattle (Bos taurus). To study the anatomy of tongue and distribution of lingual papillae on Bison bonasus hybrid tongue, a stereomicroscopic and scanning electron microscopic observations was conducted. We aimed to study the appearance of macro‐ and microscopic traits in relation to parental species and other bovids. Results indicate that Bison bonasus hybrid tongue possesses characteristic traits for parental species and ruminants from Bovidae family and also species‐specific features differ from mentioned animals. Specific new traits in hybrid are: V‐shaped arrangement of lingual papillae on ventral surface of the tongue, rosette arrangement of conical papillae on the top of lingual prominence, bigger number of vallate papillae and closer arrangement of vallate papillae. In hybrid observed also the appearance of combination of parental traits. Similar to European bison are rectangular shape of lingual prominence and absence of filiform papillae on the root of tongue. Presence of lateral processes of filiform papillae on the apex of tongue, and arrangement of vallate papillae into two rows corresponded to cattle. Development of new morphological features of tongue and its mucosal papillae in Bison bonasus hybrid opens new issue for future studies on organs of digestive system in animals after hybridization.