A comparative ultrastructural study of the pecten oculi in adult,juvenile, and nestling yellow‐legged gulls,Larus michahellis (Naumann, 1840)

This study aimed at examining the histological structure of the pecten oculi in the adult yellow‐legged gull, Larus michahellis, and at two moments of postnatal development: during the posthatch (nestling) and juvenile periods. Particular attention was paid to differences in the diameter of vessels, the thickness of the basement membrane, and ultrastructural features of endothelial and pigmented stromal cells. Capillary endothelial cells displayed numerous microvillous‐like folds projecting from their internal and external surfaces. Intercellular spaces between capillaries were occupied by pigmented stromal cells. The ultrastructure of pecten oculi underwent noticeable changes during postnatal development. The examination of the capillaries in nestlings, juveniles, and adults revealed that the formation process of vessels and pigmented stromal cells did not complete itself in the posthaching phase. The prominent feature of endothelial cells of capillaries in nestlings was that the microvilli were longer than in juvenile and adult cells, and the capillary lumen was therefore reduced. In this sense, their pigmented stromal cells showed fewer melanosomes, lacked intercellular spaces, and cellular junctions could still be observed. These results provide evidence that the pecten oculi during the posthatching phase maintains immature morphological features consistent with a role of pigmented stromal cells in the blood‐retina barrier.     

Morphology of the tongue and laryngeal entrance in the Common pheasant (Phasianus colchicus); a light and scanning electron microscopic study

The present work was carried out to describe morphological features of the tongue and laryngeal entrance of the Common pheasantPhasianus colchicus, using light and scanning electron microscopy. The lingual apex was taper-shaped with a shallow median sulcus. A V-shaped papillary crest with 15–20 caudally directed conical papillae was located between the radix and corpus linguae. The second row of papillae consisting of three caudolaterally directed conical papillae was arranged caudal to the main papillary crest. The mons laryngealis was equipped caudally with a double-layer of large conical papillae as pharyngeal crest, and few small conical papillae were seen around the glottis. Scanning electron microscope (SEM) observation showed that the apex linguae and corpus were covered with compact filiform papillae, while the radix linguae were free of papillae. Numerous openings of salivary gland can be seen on the radix linguae and mons laryngealis at higher magnification. On histological sections, all parts of the tongue and mons laryngealis were covered with a keratinised stratified squamous epithelium. The keratinised layer became thinner rostro-caudally. The simple alveolar salivary glands were distributed in the submucosa from the apex linguae to the radix linguae as well as the mons laryngealis. PAS staining revealed mucin-secreting activity of this glands. According to the findings, although the tongue and laryngeal entrance of the Common pheasant is characteristics of a galliform bird, it has some features similar to passeriformes and falconiformes.     

The scanning electron and light microscopic structure of bovine tactile hair

Bovine tactile hairs in skin samples from the lateral side of the upper lip were examined using scanning electron and light microscopy. The root of these hairs has a variable length and is surrounded by a large sinus located between the internal and the external dermal sheath. With a prominent thickness, the external dermal sheath forms the external wall of the tactile hair and contains many nerves some of which extend into trabeculae. Trabeculae projecting from the internal dermal sheath and attaching to the external dermal sheath with two or more branches are present in the entire sinus. The trabeculae are interconnected by connective tissue sheets that support the integrity of the trabecular organization. The sinus surfaces as well as trabeculae are lined by endothelia. As a result, the bovine tactile hair is truly a cavernous type of tactile hair with a well organized microscopic anatomy. Thus, the bovine tactile hair most likely plays an important role in relatively immobile and insensitive bovine lips.     

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.     

The clinicopathologic, light, and scanning electron microscopic features of eperythrozoonosis in four naturally infected llamas

The hematologic, biochemical, and light and scanning electron microscopic features of eperythrozoonosis in four llamas are described. One female and three male yearling llamas were presented for evaluation of chronic weight loss. Three of four llamas had historical evidence of chronic inflammatory conditions. On examination, multiple clinical problems were apparent, including poorly to non-regenerative anemia, inflammatory disease, and hypoproteinemia. Coccoid- and ring-shaped basophilic organisms were present on the erythrocytes of all the llamas. On scanning electron microscopy, individual, pairs, and clusters of coccoid-shaped organisms were present on the erythrocytes. The organisms measured 0.4 to 0.6 micron in diameter and caused no marked deformation of the erythrocyte membrane. A rare organism could be found that produced a slight indentation into the erythrocyte membrane. The light and scanning electron microscopic morphologic features suggested that the organism was an Eperythrozoon. Serial evaluation of serum iron concentrations of the llamas showed a decrease serum iron in all animals, with a concurrent decrease in the total iron binding capacity and percent transferrin saturation in two of the llamas. Common abnormalities seen on serum electrophoresis included a decrease in albumin and beta serum fraction in all llamas and a decrease in the gamma globulin fraction of two individuals.     

A light and scanning electron microscopic study of the epididymis active state of the endemic Mexican rodent Peromyscus winkelmanni (Carleton) (Rodentia: Muridae)

The macroscopic and microscopic anatomy of the epididymis of the sexually mature Peromyscus winkelmanni (carleton) was examined using light and scanning electron microscopy. The epididymis was divided into three regions: caput, corpus and cauda. The epididymal duct was lined with columnar and cubic epithelium with stereocilia and covered by a muscular connective tissue sheath. Capillaries appear to penetrate directly into the epithelium from the underlying connective tissue in the initial segment. The epididymal epithelium presents four cell types: principal, basal, apical and clear cells. Based on morphological differences (height of epithelial cells, length of the stereocilia, luminal area, larger diameter and spermatic index), the epididymis of P. winkelmanni, presents seven zones. The stereocilia of the epididymal ducts of zones I, II, IV and V are thick and tall, while in zone III they are thin and short. The stereocilia in zone VI are thin, while in zone VII they are short but thick. The secretory products observed in the lumen of the epididymal ducts have vesicular, granular and fibrous form in the seven zones. This study contributes to an understanding of the morphofunctional features of the epididymis in sperm maturation in a species that shows seasonal reproductive activity.     

The gastrointestinal mucosa in young milk-fed calves. A scanning electron and light microscopic investigation

Gastrointestinal segments from 4 healthy, 17-, 21-, 22- and 23-day-old calves fed on whole cow’s milk were examined. Scanning electron microscopy showed that the anterior duodenum had short villi varying in shape from leaf-shaped to nodular; the middle duodenum had broad, tongue-shaped villi and the anterior, middle, and parts of the posterior jejunum had slender, finger-shaped or leaf-shaped villi. The villi of the mucosa covering Peyer’s patches in the posterior jejunum were short and either conical or tongue-shaped; there were also small “pseudovilli” caused by bulges in the lymphoid tissue. Morphometry showed that the villi were longer in the anterior jejunum than in the duodenum and the posterior parts of the jejunum (P < 0.005). Morphologically fat absorption was most heavy in the anterior third of the small intestine. Moderate amounts of fat were also found in the epithelium of the posterior jejunum and of the abomasum. Large fat droplets were seen in apical duodenal enterocytes, in contrast to the small epithelial droplets in other areas with fat absorption. Nile blue staining indicated that the fat in the large droplets was esterified.     

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.     

The spleen of Zaedyus pichiy, (Mammalia,Dasypodidae): a light and electron microscopic study

Armadillos are ancient mammals important as models for biomedical, evolutive and ecological studies, because they have adaptive and primitive morpho-physiological characteristics. In this work we study the splenic microarchitecture of the 'Patagonian Piche', Zaedyus pichiy, as an attempt to understand the relationship between the organizational plan of the organ and the particular features of this species. The organ samples were classically processed for light and electron microscopic study. The microanatomy of the organ as well as its different cell types are studied. The spleen is non-sinusoidal, with the typical arrangement for storage functions. White pulp is well defined. Red pulp is a meshwork of circulating, immunocompetent and haemopoietic cells. The general structure of the organ agrees with the semi-fossorial habit and the adaptability of the species. Comparative aspects with other armadillos or other less specialized groups are discussed. Persistence of haemopoietic spleen activity in the adult suggests the existence of specific inductive functions of the stroma. Better knowledge of spleen structure and function in ancient mammals may give important information about their phylogeny.     

A light and electron microscopic study of the leukocytes of channel catfish (Ictalurus punctatus)

A light and electron microscopic study of channel catfish (Ictalurus punctatus) white blood cells was carried out. The white blood cells of channel catfish consist of lymphocytes, neutrophils, thrombocytes and monocytes. A fifth cell type is illustrated and described which could not be characterized. These leukocytes are characterized and compared with their mammalian counterparts.     

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.     

Site adaptations of Acanthogyrus (Acanthosentis) tilapiae: Observations through light and scanning electron microscopy

Acanthogyrus (Acanthosentis) tilapiae parasites were collected from the intestines of 300 fish belonging to three tilapia species sourced at the River Nile, Giza, Egypt. The proboscis of the parasite was characterized by three rows of hooks that curved towards the posterior of the body. The first row is supported by unmodified hooks. The parasite tegument has a series of alternative folds and a large number of pores. Sensory ganglia are located on the surface of the proboscis and body. Acanthogyrus (Acanthosentis) tilapiae provokes an aggressive host response indicated by hyperplasia of the intestinal goblet cells and focal eosinophil infiltrations. This acanthocephalan parasite shows a highly modified adaptation to its site of host infection.     

Morphological and scanning electron microscopic study of the gonadal arterioles in the Tibetan sheep

This research aimed at revealing the structural features of Tibetan sheep's testicular and ovarian vasculature and providing theoretical basis for Tibetan sheep's physiological adaptability in plateau and low-oxygen environments. Through scanning electron microscopy, corrosion casts of the feature of the gonad arterioles were observed and analysed. The results of this study found that centrifugal arteries, centrifugal and centripetal arterioles were distributed in a ‘dendritic’ fashion in the testis lobule, the ovarian arteries and arterioles, which had a spiral shape. Testicular Tibetan Sheep knot-like artery had a denser spiral structure, and there were more branches in the microarteries. On the testis lobule and arteriole of caput epididymidis, the arteriole surface shows the ‘fusiform’ indentation to be more shallower. The ovarian artery had a higher degree of helix; its surface was distributed like a ‘bark-like’ indentation; and the ring was narrower and denser. Nevertheless, the arteriole network had a high concentration and a wide number of branches, as that of the ovarian arteriole network which had more end branches, the surface of the arterioles of ovaries and testicles was scarred and denser. The studies indicate that the structural features of testicular lobule, epididymal arterioles and ovarian arterioles are more conducive to increase the oxygen supply to the gonads tissue and controlling blood flow velocity and metabolism to respond to high altitudes and low-oxygen environments.