Scanning electron microscopy study of the lingual papillae in the European mole (Talpa europea, L., Talpidae)

The tongue in the adult European mole (Talpa europea L.) was examined by scanning electron microscope. The elongated tongue with a rounded apex is about 12-13 mm in length and 3-4 mm in width. On the apex the shallow median groove is present. On the dorsal surface of the lingual mucosa two types of mechanical papillae and two types of gustatory papillae were observed. Mechanical papillae are represented by numerous filiform papillae with a single process, covering the whole surface of the apex and body of the tongue, and massive conical papillae, found on the root of the tongue. The structure and density of filiform papillae varies in the anterior and posterior part of the tongue. A unique trait of the tongue in the European mole is the occurrence on the apex of the tongue of a single row of conical papillae. Gustatory papillae are represented by numerous fungiform papillae and one pair of vallate papillae. Dome-shaped fungiform papillae in the anterior part of the tongue are arranged linearly along both margins of the tongue, whereas in the posterior part of the body of the tongue flat fungiform papillae are distributed evenly among filiform papillae. Oval vallate papillae are surrounded by a continuous furrow and a single pad. In the posterior part of the root behind conical papillae the surface of the mucosa is flat with numerous orifices of lingual papillae located there. Observations on the distribution and structure of gustatory papillae in the common mole did not show the existence of special traits, differing them from those in terrestrial insectivores. The comparison of the morphology of the tongue, the distribution and structure of the lingual papillae in the European mole with those in the other species of Insectivores, indicated of a general similarity of features within the family Talpidae.     

Morphological study of the lingual papillae in the barking deer, Muntiacus muntjak

The morphology of the tongue of the adult barking deer, Muntiacus muntjak, was examined by light and scanning electron microscopy. The result showed that the tongue of the barking deer was elongated with a rounded apex. Four types of lingual papillae were observed: filiform, fungiform, vallate and large conical papillae. The filiform papillae represented the most numerous types of lingual papillae. The fungiform papillae were distributed among the filiform papillae on the rostral and the body portions of the tongue. Ten to thirteen vallate papillae were distributed on both sides of the lingual prominence among the large conical papillae. Histologically, both the fungiform and vallate papillae contain taste buds in the epithelial layer. The distribution and types of lingual papillae found in the barking deer are similar to those in the other species that belong to the family Cervidae.     

Morphogenesis of lingual papillae of one‐humped camel (Camelus dromedarius) during prenatal life: A light and scanning electron microscopic study

This study was made on 24 camel fetuses of crown‐rump vertebral length (CVRL) ranging from 10.5 cm to 105 cm CVRL (94–352 days old). These camel fetuses were classified into three groups representing the three trimesters of prenatal life. During the first trimester (94–142 days), lingual papillae (circumvallate and lentiform papillae) were demonstrated on the lingual root, but lingual body and the apex were almost free of papillae except for some scattered epithelial projections especially near the lateral borders of the body. In the second trimester (152–229 days), the lentiform papillae covered the entire root of the tongue except for areas occupied by the circumvallate papillae. Taste buds with clear pores were observed for the first time in areas between the circumvallate gustatory furrow and surface epithelium of the tongue. In addition, short numerous filiform papillae were observed on the rostral part of the lingual body and the lateral parts of the apex. Fungiform papillae, however, were demonstrated amidst the filiform papillae. In this trimester, taste buds were also seen on the top of the fungiform papillae. In the third trimester (256–352 days), all lingual papillae were clearly demonstrated on the dorsum of the root, body and apex of the tongue. Both types of gustatory papillae (circumvallate and fungiform) had well‐developed taste buds. Mechanical papillae (filiform and lentiform) were well developed. Lentiform papillae occupied most of the dorsal aspect of the Torus linguae; they were larger in size with semicircular apices. Filiform papillae, however, were numerous and demonstrated heavily on the lateral and rostral parts of the body as well as on the apex of the tongue.     

Morphological study of the lingual papillae in the fruit bat (Rousettus amplexicaudatus) by scanning electron microscopy and light microscopy

This study was carried on the tongues of ten normal, healthy and adult fruit bats (Rousettus amplexicaudatus, also known as the nyap biasa bat) in Yogyakarta, Java Island, Indonesia. The tongue was protrusible, elongated and flat with a rounded apex, and its width and thickness increased gradually towards to lingual root. There were two main types of lingual papillae, mechanical (filiform) and gustatory (fungiform and circumvallate). The tongue was divided into three parts (apex, corpus and radix), and then, each part was subdivided into three regions (two lateral regions and a median region). There were six subtypes of the filiform papillae—three types on the anterior part (small, scale-like and giant), one type on the middle part (leaf-like papillae) and two types on the posterior part (rosette-shaped filiform and conical filiform papillae)—in addition to transitional papillae presented on the corpus and radix. Two types of gustatory papillae were represented by a small number of fungiform papillae that are scattered among the filiform papillae on the lingual apex and corpus, while three circumvallate papillae on the posterior part are arranged in a “V” shape pointing directly at the larynx.     

Morphological Studies of the Tongue of the Egyptian Water Buffalo (Bubalus bubalis) and Their Lingual Papillae Adaptation for Its Feeding Habits

This work was conducted to describe the morphological characters of the tongue of Egyptian water buffalo (Bubalus bubalis). The lingual root and the dorsal middle region of apex and body in addition to the dorsal and ventral surface of lingual tip were devoided from any fungiform papillae. The lingual tip contains conical papillae only. The ventral surface of lingual apex was divided into two portions by the U‐shaped fungiform line into papillary and non‐papillary region. Histological investigation on the lingual surface epithelium and lamina propria submucosa reflects differences in these layers in different parts of the tongue. By SEM, there are two subtypes of filiform papillae: caudally directed papillae on dorsal surface and rostrally directed papillae on the lateral region of ventral surface of lingual apex. There are two subtypes of conical papillae: small slightly rostrally directed papillae on dorsal and ventral surface of lingual tip and large posteromedially directed papillae on dorsal surface of lingual root. The rounded circumvallate papillae consisted of round bulb surrounded by deep circular groove, which surrounded by circular pad. Higher magnification of filiform papillae indicates the presence of microcrests separated by microgrooves, and these microgrooves consisted of microrodes. The fungiform surface having micropores on the tip of elevated tubercle for taste buds pores. All these observed structures (microcrests, microgrooves, microrodes, tubercles, microridges) in a higher magnification allow animals to transport food particles through the oral cavity and help in the defensive behaviour. There are strong correlations between the tongue anatomical characteristics and its functions.     

Morphological and scanning electron microscopic studies of the tongue of the Egyptian fruit bat (Rousettus aegyptiacus) and their lingual adaptation for its feeding habits

This study was carried out on the tongues of 12 adult normal healthy Egyptian fruit bats of both sexes. The tongue is protrusible, elongated flat with a rounded apex and its wide and thickness increase gradually toward the lingual root. There are four types of lingual papillae; two mechanical and two gustatory. The tongue divided into three parts (anterior, middle and posterior), each part subdivides into three regions; two lateral regions and median region, in addition to the lingual apex to the anterior region. The lingual papillae close to the median region of the tongue were posteriorly directed toward the pharynx, while theses present on the lateral regions of the tongue are directed medioposteriorly. There are sex subtypes of the filiform papillae; three on the anterior part (small, conical and giant), two on the middle part (cornflower and leaf-like papillae) while the posterior part contain rosette shape filiform papillae, in addition to transitional papillae and conical papillae. Two gustatory papillae represented by; small number of fungiform papillae which scattered among the filiform papillae on lingual apex and two lateral regions of the anterior and middle part of tongue, while the three circumvallate papillae on the posterior part were arranged in a triangle form.     

Morphological features of the Egyptian Ossimi sheep tongue: New scanning electron microscopic insights into its papillary system adaptations to Egyptian ecological conditions

The current study aims to illustrate the gross and scanning electron microscopic characterizations and ultrastructural adaptation of the lingual papillary system of Egyptian Ossimi sheep to Egyptian ecological conditions. The tongue had three regions: the apex (with a slightly bifurcated tip), the body (subdivided into rostral and caudal parts) and the root (subdivided into rostral papillary and caudal non-papillary parts). Torus linguae had two parts: the triangular rostral part (the caudal part of the body) and the quadrilateral wide part (the rostral part of the root). The lingual papillary system had mechanical (filiform, conical and lentiform) and gustatory (fungiform and circumvallate) types. Filiform papillae were heavily scattered on the dorsal surface of the apex, the rostral part of the body and the ventral surface of the papillary region of the tip. Filiform papillae had five subtypes (ventral and dorsal processed, triangular, leaf-like and triangular-processed papillae), while the conical papillae had three subtypes: two lingual (small, large) and one paralingual (elongated pointed), and the fungiform had two subtypes: the high-density ovoid (on the ventral surface of the tip) and round papillae (on the dorsal surface) that possessed a high number of taste pores, not previously described. They ranged from 5 to 10 for ovoid and 25 to 25 for round papillae. Each circumvallate papilla had an ovoid bulb (with 2–5 taste pores) encircled by an annular groove and two pads (i.e. not described previously). The papillary system's regional divergence was specialized for their harsh and semi-harsh diet.     

Morphology of the dorsal lingual papillae in the Japanese macaque and Savanna monkey

The dorsal lingual surfaces of infant Japanese macaque (Macaca fuscata) and adult savanna monkey (Cercopithecus aethiopus) were examined by scanning electron microscopy. Filiform, fungiform, foliate and vallate papillae were found. The filiform papillae were distributed over the entire dorsal surface of the tongue. The fungiform papillae were round in shape, and more densely distributed on the lingual apex. The foliate papillae were seen on the dorsolateral aspect of the tongue. The three vallate papillae were arranged like a triangle with the apex of the triangle directing caudally. Each papilla was surrounded by a groove. The rudiments of the fungiform, foliate and vallate papillae were visible earlier than those of the filiform papillae.     

Morphology of the dorsal lingual papillae in the black rhinoceros (Diceros bicornis)

The dorsal lingual surface of a black rhinoceros (Diceros bicornis) was examined by scanning electron microscopy. The tongue was about 30 cm in length. There were about 60 vallate papillae on both sides. Filiform, fungiform and vallate papillae were found. The filiform papillae were distributed over the entire dorsal surface of the tongue. The papillae had a hair-like shape. The fungiform papillae were round in shape, and more densely distributed on the lingual apex. No foliate papillae were seen on the dorsal surface. The vallate papillae were located on both sides of the posterior end of the lingual body. Each papilla was surrounded by a groove.     

Anatomical and scanning electron microscopic study of the tongue in the African giant pouched rats (Cricetomys gambianus,Waterhouse)

The African giant pouched rat is a nocturnal, fossorial and omnivorous wild rodent widely distributed in sub‐Saharan Africa. The morphology of lingual surface has not previously examined and was investigated by gross dissection, stereomicroscopy, scanning electron and light microscopy. Grossly, it was elongated and dorso‐ventrally flattened with rounded tip. It measured 3.48 ± 0.33 cm in length, with a median groove of 1.4 ± 0.1 cm in length and well‐developed lingual prominence. Stereomicroscopically, filiform, fungiform and vallate papillae were indicated in the apex, body and root. Fungiform papillae intermingled with filiform on the ventral and dorsal surface of the apex and body. Three vallate papillae were located in triangular arrangement on the root. The surface ultrastructural features distinguished four types of filiform which varied in size, shape and distribution: first type with long pointed process was preponderant on the apex and body of tongue; the second with robust base was located on central lingual prominence; the third (caudal body) was conically shaped with pointed process; and the fourth type (root) had forked filamentous process. Large oval‐shaped fungiform papillae were apparent. Each vallate was surrounded by a circumferential groove into which taste pores opened. Histologically, the tongue surface displayed moderately keratinized stratified squamous epithelium, and lamina propria that varied in places. Fungiform and vallate showed spindle‐shaped taste buds. Serous and mucous acini containing neutral and acidic mucins were observed in lamina propria of root. The structural adaptations of the tongue to omnivorous diet and food manipulation in oral cavity were comparatively discussed.     

Tongue Papillae in Goat: a Scanning Electron-Microscopic Study

The tongue papillae of 6-9-month-old Jamunapari goats were studied by scanning electron-microscopy. The conical-shaped filiform papillae had 3–6 pointed projections and 6–8 secondary papillae at the free tip and the base of the dorsal surface of the tongue, respectively. The convex surfaced fungiform papillae were raised above the lingual mucosa. The vallate papilla was characterized by a papillary groove and an annular pad. The large conical papilla had a round base and a blunt tip without any projection. Two types of lenticular papillae could be distinguished. The irregular surface of all types of papillae revealed microplicae in the form of microridges and micropits. The fungiform papilla was studded with microvilli. The taste pores were oriented on the dorso-lateral surface of the vallate papilla.     

Papillary architecture of the Leopardus pardalis tongue

The ocelot (Leopardus pardalis) is a Felidae of wide geographical distribution and food flexibility; therefore, it is essential to understand the morphology of the species. Thus, we aimed to describe its lingual morphology in order to gain information regarding the anatomy of this carnivore's digestive system. The tongues ??were removed for ex situ macroscopic and morphometric analyses, as well as for light microscopy and scanning electron microscopy, of fragments of the different lingual regions. The tongue of L. pardalis had an elongated form that was subdivided into the apex, body and root, in which four papillary types were observed: filiform, fungiform, circumvallate and conical. It presented with a stratified, keratinized squamous epithelium, followed by loose and dense connective tissues, as well as a skeletal striated musculature that comprised most of the organ. In addition, in scanning electron microscopy the filiform papillae showed a complex with multiple layers of keratin with triangular shape projected caudally in oral cavity. The fungiform papillae were distributed among the filiform and showed a rounded shape with some gustatory pores, and are keratinized but in a lower intensity if compared with filiform. The vallate papillae, located in lingual root, showed an oval format, had a deep groove surrounded the papillae and some gustatory pores. The conical papillae are located in lingual root and are similar to the filiform. The tongue of L. pardalis resembles other carnivorous species, mainly among felids. However, it differed in relation to the quantity of vallate papillae and the absence of foliate papillae.     

Scanning Electron Microscopic Study of the Lingual Papillae in the Arctic Fox (Alopex lagopus L., 1758)

This study aims to show the distribution and the three-dimensional structure of the lingual papillae in the arctic fox. The macro- and microscopic structure of the tongue and its lingual papillae was studied in 11 adult arctic foxes. Two types of mechanical papillae were distinguished on the dorsal surface of the tongue – filiform papillae and conical papillae. The gustatory papillae in the arctic fox are represented by fungiform, vallate and foliate papillae. The keratinized filiform papillae on the anterior part of tongue are composed of one big posterior process accompanied by 10–12 secondary anterior processes. The number of anterior processes of filiform papillae undergo a complete reduction within the area between the posterior part of the body of the tongue and area of the vallate papillae. The conical papillae cover the whole dorsal surface of the root of the tongue, including the lateral parts surrounding the area of the vallate papillae and the posterior part of the root. The size of the conical papillae increases towards the root of the tongue but their density decreases. In the arctic fox, there are three pairs of vallate papillae distributed on the plan of a triangle. The diameter of vallate papillae in each successive pair is bigger. The wall surrounding the body of the vallate papilla and its gustatory trench is composed of six to eight conical papillae joined at various degree. The foliate papillae on both margins of the tongue consist of seven to nine laminae.     

Characteristics of Filiform, Fungiform and Vallate Papillae and Surface of Interface Epithelium-Connective Tissue of the Maned Sloth Tongue Mucosa (Bradypus torquatus, Iliger, 1811): Light and Scanning Electron Microscopy Study

The study of lingual surfaces and the surface of interface epithelium-connective tissue of the tongue of Bradypus torquatus was performed by employing the light and scanning electron microscopy (SEM) techniques. The results revealed that the rostral part of the tongue presents a round apex and covered by filiform and fungiform lingual papillae and a ventral smooth surface. It was observed that the epithelial layer of the dorsal surface possesses the basal, spinosum, granular and cornified epithelial cells. The lamina propria is characterized by a dense connective tissue forming the long, short and round papillae. Numerous typical filiform papillae are located especially in the rostral part intermingled for few fungiform papillae, which were revealed in three-dimensional SEM images. Usually, the fungiform papillae are located in the border of rostral apex of the tongue exhibiting the rounded form. They are covered by keratinized epithelial cells. In the fungiform papillae, several taste pores were observed on the surface. The vallate papillae presented numerous taste buds in the wall of epithelial cells, being that the major number of taste buds is located on the superior half of vallate papilla. The taste pores are surrounded by several laminae of keratinized epithelial cells. The samples treated with NaOH solution and examined by SEM revealed, after removal of the epithelial layer, the dense connective core in original disposition, presenting different sizes and shapes. The specimens stained with Picrosirius and examined by polarized light microscopy revealed the connective tissue, indicating the collagen fibres type I and type III.     

Characteristics of Dorsal Lingual Papillae of the Bactrian Camel (Camelus bactrianus)

The morphology of dorsal lingual papillae of the Bactrian camel (Camelus bactrianus) was studied by using light and scanning electron microscopy. Filiform and lenticular papillae were considered as mechanical papillae but fungiform and vallate papillae were considered as gustatory papillae. Filiform papillae were distributed mostly in the anterior two-thirds region of the tongue. Each filiform papilla consisted of one primary papilla and a few smaller secondary papillae. Lenticular papillae were distributed on the torus linguae. The larger papillae were arranged in two parallel lines medially whereas the smaller papillae were laterally located. Most of the fungiform papillae were found on the lateral margins of the anterior two-thirds of the tongue. These papillae were small and round. Intra-epithelial taste buds were located on the dorsal surface of each papilla. The vallate papillae were arranged in two rows on each rim of the torus linguae. Each round- and flat-shaped vallate papilla was surrounded by a prominent gustatory groove and an annular pad. A few taste buds were observed in the lateral epithelium of the papillae. The keratinization of the covering stratified squamous epithelium of the mechanical lingual papillae was relatively thicker than those of the gustatory papillae. The lingual papillae of the Bactrian camel exhibited some different characteristics from other domestic ruminants. These morphological characteristics of the tongue of the Bactrian camel might have evolved to assist the camel in prehension and manipulating of the inorganic stiff plants that grow in its environment and therefore might relate to the feed and feeding habits of the animal.     

Ultrastructure of Lingual Papillae in Common Chimpanzee (Pan troglodytes) Foetus,Newborn and Adult Specimens

Among primates, the two recognized species of chimpanzees (common chimpanzee, Pan troglodytes; pygmy chimpanzee, Pan paniscus) are considered to be the most similar to humans. Importantly, in mammals, the food intake behaviour largely determines the tongue morphology, including the type, proportion and distribution of gustatory and non‐gustatory tongue papillae. The lingual papillae form during its development and mature in post‐natal life depending on the different feeding. In this study, we have used scanning electron microscopy to analyse the age‐related changes in the lingual papillae of foetal, newborn and adult P. troglodytes. Four main types of lingual papillae, denominated filiform, fungiform, foliate and vallate, and one subtype of filiform papillae called conical papillae, were found. The main age‐related changes observed in all kinds of papillae were a progressive keratinization and morphological complexity along the lifespan. During the foetal period, there was scarce keratinization, which progressively increases in young animals to adulthood. The number of filiform increased with ageing, and both filiform and fungiform papillae in adult tongues are divided into pseudopapillae. On the other hand, the vallate papillae vary from smooth simple surfaces in foetal tongues to irregular surfaces with grooves and pseudopapillae (microscopic papilla‐shaped formations within the papilla itself) in adults. These results describe for the first time the age‐related variations in the three‐dimensional aspect of lingual papillae of the chimpanzee tongue and provide new data to characterize more precisely these structures in the human closest specie.     

Etude Morpho-fonctionnelle des Papilles Linguales chez le Boeuf (Bos taurus)

The morpho-functional and topographical features of the lingual papillae situated on the dorsal surface of the bovine tongue, were studied utilizing LM and SEM techniques. In the bovine species, the functional differentiation of the lingual papillae in their gustative and mechanical modes, seems to be related to the position of the papillae rather than to their morphological features. The gustative function predominates over the mechanical one on the caudal tract of the tongue body (lateral to the lingual torus and associated with circumvallate papillae). The gustative function also involves the conical papillae situated on the caudal tract of the tongue body. This gustative function is aided by additional anatomical structures: 1. The grooves situated on the rostro-lateral side of the conical papillae; 2. The microcraters located on the top of the fungiform papillae; and 3. The furrows of the circumvallatae papillae vallum. The contact between saliva soluble food particles and taste buds is aided and made more efficient by these structures. Furthermore, a large variety of conical papillae were observed, whereas no filiform papillae were noted.     

Investigations on the light and scanning electron microscopic structure of the lingual papillae in the angora goat (Capra hircus): II. Mechanical papillae

This study was conducted to examine the light microscopy (LM) and scanning electron microscopic (SEM) structures of mechanical papillae on the tongue in the Angora goat (Capra hircus). As study materials, the tongues of four adult female Angora goats were used. The samples were collected from the dorsal surfaces of the apex, body, root and torus of the tongue and the ventral surfaces of the lingual apex for light and scanning electron microscopic examinations. Three types of mechanical papillae were seen in Angora goat tongue: papilla filiformes, papilla lentiformes and papilla conicae.The filiform papillae were detected in the dorsal surface of the tongue from lingual apex to lingual torus, and in the ventro-lateral of the lingual apex and on both sides of the lingual torus. The morphological differences were observed in filiform papillae according to their location in the tongue. The lenticular papillae settled on the centre of the lingual torus. Two types of these papillae, irregular-round and pyramid-shaped were identified. The conical papillae were scattered all over the lingual torus, except for the central part and were also seen on the root of the tongue. In the light microscopic examination, it was found that mechanical papillae had a stratified squamous epithelium and a varying degree of keratin layer on epithelial surfaces. In this study, by examining the light and scanning electron microscopic structure of the mechanical papillae in the Angora goat tongue, their similarities and differences with other domestic and wild ruminant species were determined.