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Subject: Veterinary Anatomy Ɨ End date: 2009 Ɨ Start date: 2000 Ɨ Thesis Type: M.V.Sc. Ɨ
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    ThesisItemOpen Access
    Post-hatch development of preen gland in the duck (anas platyrhynchos)
    (Department of Anatomy, College of Veterinary and Animal Sciences, Mannuthy, 2005) Rajathi, S; KAU; Ashok, N
    The study on the post-hatch development of the preen gland in ducks was conducted using 44 ducks from the day of hatch to 150 days of age. The project was taken up to trace the structure and development of the glands and their relationship with the age and body weight. After recording gross relations and measurements, the material was fixed using various fixatives for studying the cellular details, arrangement of cells, connective tissue framework, micrometry and histochemistry. The preen gland was a paired organ with two gland and a common cylindrical papilla together formed a ā€˜Vā€™ shaped structure. Each gland was pear shaped and pale yellow in colour, in fresh state. They were located on the dorsal surface of the pygostyle. The two glands had separate ducts. The uropygial circlet was seen at the tip of the papilla. The glands were vascularized through a pair of branches from the caudal artery and innnervated through the medial caudal nerve. The weight of the preen glands increased progressively from the day of hatch to 150 days of age. This weight was positively correlated with the age and body weight. The proportion of the gland weight to body weight showed a decreasing trend. The right gland was slightly heavier, longer, wider and thicker than the left. The length, breadth and thickness were positively correlated with age and body weight. Simple, branched, tubular and holocrine type of glands was covered by highly vascular connective tissue capsule composed of collagen and reticular fibres. Elastic and smooth muscle cells were absent. The secretory tubules showed two zones, an outer zone or zone I, near the capsule and an inner zone or zone II, towards the primary cavity. The epithelium of the tubules consisted of basal, intermediate and transitional cell layers. The papilla had two ducts, which were lined by glandular epithelium initially and keratinized type of stratified stratified squamous epithelium at the tip. The glandular epithelium was surrounded by longitudinally arranged smooth muscle fibres and skin. Lamellar corpuscles and circlet feather follicles were noticed in the papilla. Capsule, trabeculae and the parenchyma were PAS positive. Acid mucopolysaccharides and glycogen were not detected in the gland. Lipids were evident uniformly in all the cell layers. The acid phosphatase activity was moderate in the basal and intermediate layers and strong in the transitional layer. The alkaline phosphatase activity was moderate in the basal and intermediate layers and weak in transitional layer of outer zone. It was moderate in the basal and intermediate layers and intense in the transitional layer of inner zone. Micrometrical findings on the capsule thickness, width of outer and inner zones and the primary cavity increased with the advancement of age.
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    ThesisItemOpen Access
    Prenatal development of major lymphocenters and lymphatics in goats (Capra hircus)
    (College of Veterinary and Animal Sciences, Mannuthy, 2009) Asha, Antony; KAU; 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.