Browsing by Author "Maya, S"

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Postnatal development of the upper digestive tract in the Japanese quail
(Department of Anatomy, College of Veterinary and Animal Sciences, Mannuthy, 1995) Maya, S; Lucy Paily
The structure and postnatal development of the upper digestive tract of Japanese quails were studied using 72 birds aged from day-old to 60 days for proper understanding of their functional peculiarities. The growth, morphology and histology of the tongue, pharynx, cervical and thoracic parts of oesophagus, crop, proventriculus and gizzard were studied using six birds at each age group. The age groups studied were at three days interval upto 15 days and thereafter at five days interval upto 30 days and then at ten days interval upto 60 days of age. Maximum weight of each part was recorded at 60 days of age. But maximum contribution to body weight by each part occurred within the first week of age. The tongue, pharynx and oesophagus were lined by stratified squamous epithelium, which showed keratinization on the anterior two-third of the ventral surface of the tongue and on the papillae of the tongue and pharynx. Filiform, conical and fungiform papillae were present on the base of the tongue. The rostral lingual glands contained both serous and mucous end pieces, but posterior glands showed only mucous cells. The taste buds were associated with the glandular ducts. The skeleton of the tongue showed signs of ossification from 30th day of age, with the tip of the entoglossal bone remaining cartilaginous even upto 60 days of age. In the pharynx, pharyngeal tonsil and palatine, sphenopterygoid and cricoarytenoid salivary glands were noticed. In addition to mucous and pieces the medial palatine glands exhibited serous and pieces also. Within the choanal slit and laryngeal inlet the squamous epithelium changed into respiratory epithelium. Laryngeal cartilages were cricoids, procricoid and paired arytenoids. The oesophagus was represented by a long cervical and short thoracic parts with a diverticulum, the crop. The epithelium on the top of the longitudinal mucosal folds was higher in the cervical oesophagus. Mucous glands were present throughout the oesophagus and crop but much reduced in the greater curvature of the crop and lymphoid tissue was absent at the region. Muscularis mucosa and submucosa entered into the longitudinal folds. Tunica muscularis consisted of iner circular and outer longitudinal layers of smooth muscles. Tunica adventitia was the outermost layer. A well developed oesophageal tonsil was present at the oesophago- proventricular junction. THh spindle-shaped proventriculars had a mucosa studied with minute nodules. Surface epithelium consisted of cuboidal to columnar cells. Lamina propria contained simple tubular glands. Muscularis mucosa consisted of scattered bundles of longitudinagl smooth muscle fibres. The compound tubular glands in the submucosa were lined by oxyntico peptic cells which had a dentate appearance. Tunica muscularis consisted of inner and oter longitudinal and middle circular layers of smooth muscle fibres. Outermost was the serosa. At the isthmus, the glands and outer longitudinal muscle layer of proventriculus disappeared and the lamina propria contained glands similar to those of gizzard. The biconvex dis-shaped gizzard had a greater dorsoventral diameter than cranio – caudal diameter. Internal to the serous lining was the tendon layer which was thickest at the tendinous aponeurosis and absent at the blind sacs. The lateral muscles consisted of a single layer of smooth muscle where as the blind sacs had inner longitudinal and outer circular muscle layers. Submucosa was dense and the muscularis mucosa absent. The tubular gland in the lamina propria were lined mainly by chief cells, and few basal and intermediate cells.Tall columnar cells which showed supranuclear PAS positive reaction, constituted the surface epithelium. The gizzard lining consisted of arrays of vertical columns, secreted by the tubular glands and a matrix produced by surface cells. The junction of gizzard with duodenum was marked by a constriction of muscularis mucosa forming a fold of the muscularis and tunica propria. Posterior to the fold spatula –shaped duodenal villi and coiled tubular glands with goblet cells were observed.
Prenatal development of major lymphocenters and lymphatics in goats(Capra hircus)
(Department of Veterinary Anatomy and Histology, College of Veterinary and Animal Sciences, Mannuthy, 2009) Asha Antony; Maya, S
Prenatal development of the major lymphocenters and lymphatics in goat was studied using 41 foetuses of various ages from 22 to 147 days of gestation. Morphogenesis and histogenesis of lymph nodes from five major lymphocenters, viz. parotid and mandibular from head, prescapular from neck, caudal mediastinal from thoracic cavity, jejunal mesenteric from abdominal viscera and prefemoral from abdominal wall and lymphatics, viz. tracheal and thoracic ducts and cisterna chyli were studied. During the first month, the lymphatic system presented six lymph sacs. By 22 days, paired jugular sacs and unpaired retroperitoneal sac appeared whereas, the cisterna chyli and paired iliac sacs appeared only by 24 days. Jugular sacs started to split into lymphatic spaces adjacent to the internal jugular vein and vagosympathetic trunk by 40 days. Retroperitoneal sac lay ventral to aorta, close to the root of the mesentery, near the kidney anlage and underwent regression by 53 days. Iliac sacs appeared near aorta, dorsolateral to Wolffian bodies and dorsomedial to metanephric kidneys and its onset of regression was by 50 days. Cisterna chyli appeared as a lymphatic space lateral to aorta and became a spindle-shaped dilatation at the level of last thoracic to first lumbar vertebra. By 48 days, thoracic duct formed the cranial continuation of cisterna chyli, near aorta. By 50 days, the tracheal lymph duct was seen in the developing carotid sheath. Valves appeared by fourth month in these ducts. Lymph sacs showed infiltration by lymphocytes and red blood cells by 48 days. The developing lymph nodes exhibited haemopoietic areas between 53 and 60 days. There was a progressive increase in the size of lymph nodes with age. The weight of the lymph nodes exhibited positive correlation with body weight, CRL and age. The superficial lymph nodes occurred as single ones and deep lymph nodes occurred in groups, with slight variation in position in some animals and slightly higher gross values for male animals and for the lymph nodes of right side. Capsule was undifferentiated up to 53 days and presented trabeculae by 75 days in parotid lymph node. The differentiated capsule presented dense fibrous connective tissue with collagen, elastic and smooth muscle fibers and was thicker where the cortex was more developed. Earliest aggregation of lymphocytes occurred in cortex by 60 days, in the parotid and mediastinal nodes. The nodular aggregations occurred by 75 days in the parotid lymph node, but by fifth month in all other nodes. Cortex was denser and thinner than the medulla. Medulla started differentiation by 75 days but macrophages and germinal centers were not detected till the end of gestation. Parotid and mandibular lymph nodes showed a similar pattern of development, but with a denser cortex for the latter. Prescapular lymph node presented lesser cortico-medullary differentiation than the corresponding stages in the lymph nodes of head. Even though the differentiation was slower during the initial stages, during the last month it became similar to that in the lymph nodes of head. Prefemoral lymph node followed a slower pattern of development with lesser number of trabeculae than parotid and prescapular lymph nodes. All lymph nodes presented nodular aggregation of lymphocytes in the cortex by fifth month, thereby attaining a structure similar to that in adults towards the end of gestation except for the absence of macrophages and reactive centers. Lymphocytic proliferation in the thymus preceded the appearance of lymphocytes in lymph nodes indicating these cells got differentiated first in the thymus. Contribution to the body weight of spleen and lymph nodes decreased towards the end of gestation indicating a similar development pattern. Only weak reactions were exhibited by the lymph nodes towards glycogen, acid and alkaline phosphatases and lipids. The superficial lymph nodes were encapsulated by deposition of fat from fourth month onwards.
Prenatal development of spinal cord in goats (Capra hircus)
(Department of Anatomy, College of Veterinary and Animal Sciences, Mannuthy, 2005) Maya, S; Jose John Chungath