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ThesisItem Open Access COMPUTED RADIOGRAPHIC STUDIES ON SIZE OF THE HEART BASED ON VERTEBRAL HEART SCORE IN DOGS AT DIFFERENT AGE GROUPS(SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517502. (A.P.) INDIA, 2018-12) SWETHA, PANDIKUNTA; KISHORE, P. V.S.(MAJOR); NAGAMALLESWARI, Y; RAGHUNATH, MThe present study was conducted on 54 clinically healthy dogs of either sex without any cardiac and pulmonary abnormalities. Computed thoracic radiographs available from the recorded data were studied to determine the VHS values in different skull types with one breed as representative sample in each type viz. Brachycephalic (Pug), Mesaticephalic (Labrador retriever) and Dolichocephalic (German shepherd). Dogs in each breed were divided into three age groups viz. group-I (< 6 months), group-II (7-12 months) and group III (>12 months). In Pugs, the gross anatomical size of the heart increased from the age of 6 months to >12 months on left lateral, right lateral and dorsoventral views (p<0.01). There was no significant increase in the gross anatomical size of the heart on manually measured left lateral and right lateral views. Higher VHS values were observed on the right lateral projection than on left lateral projection in both CR and manual methods in all the age groups of all the three breeds. VHS values were not influenced by the age in all the three age groups. There was no significant increase in the gross anatomical size of the heart on left lateral, right lateral and dorsoventral views both by CR and manual measurement. In a comparison of CR and manual methods, the manual VHS values were higher compared to the CR values in both lateral views in Pugs and German shepherd dogs. In Labrador retrievers, the CR VHS values were higher compared to the manual values in both lateral views. There was no significant increase in the gross anatomical size of the heart among the three age groups in the Labrador retrievers and German shepherds. There was no significant variation in the gross anatomical size of the heart up to 12 months of age and at more than 12 months of age the size of the heart was increased markedly in Pugs. In all age groups, the VHS values were highest in Pugs followed by Labrador retrievers and German shepherds, indicating that the size of the heart was larger in Pugs followed by Labrador retrievers and German shepherds. There was no correlation between the body weight and the VHS values among all the three age groups in all the three breeds. In addition to the variations among the three age groups within each breed, variations among the three breeds within the same age group were also found. Group-I showed no variation in all views. Group-II showed no variation on LL, RL and DV views. Group-III showed no variation only in DV view. All haematological and serum biochemical values calculated were within the normal reference range indicating the normal health status of the dogs.ThesisItem Open Access STUDY ON PRENATAL DEVELOPMENT OF ADRENAL GLAND OF SHEEP (Ovis aries)(SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA, 2016-10) RAJ SEKHAR, U; RAJU, N.K.B(MAJOR); JAGAPATHI RAMAYYA, P; DHANA LAKSHMI, NABSTRACT: The present work was conducted to observe the histomorphogenesis and histochemical changes in adrenal parenchyma. A total of 63 healthy embryos and foetuses irrespective of their sex were collected from pregnant sheep slaughtered from local slaughter houses of Tirupati and were divided into three groups as per their estimated approximate age. The adrenal glands attained a harvestable size around 46-47 days of gestation. At this age, the adrenals were rounded and pin head shaped and pink in colour and in later stages of development the right adrenal was pyramidal and left adrenal was bean shaped. The left adrenal was heavier, thicker and longer than the right adrenal gland in all groups. The primordium of the adrenal was first noted in 38 days old embryo and was placed cranial to metanephron and ventral to aorta. At 54 days of gestation, thick connective tissue capsule was observed. Collagen fibres, reticular fibres and nerve fibres were noticed in the capsule. However, elastic fibres were not noticed in adrenal gland through out the gestation. The mean thickness of the capsule in group II was 69.196μm ± 12.97 and in group III was 96.003μm ± 16.99 respectively. At 54 days of gestation, zona glomerulosa was formed. At 75 days of gestation, two zones were observed in the cortex i.e, outer zona glomerulosa and inner zone fasciculata. The zona reticularis is not distinctly seen in all the age groups. The thickness of the cortex increased steadily with the age of the foetus. The migration of medullary cells through the capsule was noticed at 60 days of gestation. At 100 days of gestation distinct medulla was observed in the centre of the gland. The chromaffin granules number and their size increased as the age advanced. Noradrenaline and adrenaline producing cells were also observed in the medulla. A large medullary vein was noticed in the centre of the gland. Histochemical studies of adrenal gland revealed that glycogen content was more in cortical cells especially in glomerulosa cells. The capsule showed intense positive reaction for PAS whereas cortex and medulla showed moderate to weak PAS reaction. In the present study, an intense reaction for acid mucopolysaccharides was observed in cortical trabeculae. The reaction for acid mucopolysaccharides was very weak or even absent in adrenal parenchyma. The capsule and medulla were completely devoid of lipids whereas cortex showed moderate reaction. The capsule and cortex showed intense reaction and medulla showed moderate reaction for alkaline phosphatase. The capsule and cortex showed weak to moderate reaction and medulla showed intense reaction for acid phosphatase in all the age groups.ThesisItem Open Access COMPARATIVE ANATOMICAL STUDIES ON THE OVIDUCT OF DOMESTIC FOWL AND WHITE LEGHORN(SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA, 2018-02) TARUN, MODALAVALASA; RAJU, N.K.B(MAJOR); NAGAMALLESWARI, YAMANI; SREENU, MakkenaABSTRACT: The present study was conducted on thirty six apparently healthy birds belonging to six birds each in domestic fowl and White leg horn (WLH) layers in each group. The birds were divided into three groups as group I (chick), group II (laying) and group III (non laying). The average lengths and weights of the oviduct in domestic fowl and WLH were measured. In group I chicks the mucosa was lined by simple columnar epithelium throughout the length of oviduct. In both domestic fowl and WLH of II and III groups the infundibulum consisted of anterior funnel and posterior neck regions. In tunica muscularis the outer longitudinal layer was arranged in a peculiar bundles of smooth muscle fibres so that it helps in peristaltic movement of infundibulum in transporting the grasped ova. The tunica mucosa of magnum was projected into the lumen and formed longitudinal folds, primary folds were very high and given several secondary and teritiary folds. The epithelium was pseudostratified ciliated columnar with non ciliated cells. The entire propria submucosa was occupied by densely packed tubular glands. In mucosa of isthmus the epithelium was pseudostratified columnar with secretory goblet cells and non secretory prismatic cells was observed in the birds of group II and group III. The involutionary changes appeared in the tubular glands of the group III as the disintegration of eosinophilic granules and occurrence of vacuoles in the cytoplasm. In group II the mucosal folds of the uterus were complex by varying in their size. In larger folds several secondary and tertiary folds were also present and some of these secondary and tertiary folds showed anastomosis. The mucosa of vagina formed numerous primary, secondary and teritiary folds that were elongated and thin in all the birds studied. The luminal epithelium was pseudostratified ciliated columnar and the invaginations of this epithelium served as sperm storage tubules. The inner circular layer was strong which formed vaginal sphincter at the opening of cloaca. The serosa was thick with abundant collagen, reticular fibres and numerous small blood vessels in all the birds studied. The secretory cells of lining epithelium of mucosal folds in infundibulum, magnum, isthmus, uterus and vagina showed PAS +ve reaction indicated the presence of mucopolysaccharides in both domestic fowl and WLH of group II. The non secretory cells of the lining epithelium in mucosal folds of oviduct in the birds of both group II and group III showed the glycogen content at the apical regions of the cells. The pyramidal cells of tubular glands in the uterus of domestic fowl and WLH in group III showed a few lipid droplets in the cytoplasm. The intense calcium mineralization was observed at the apical part of secretory cells in the lining epithelium of mucosal folds of the uterus in both the birds of group II.ThesisItem Open Access STUDY ON HISTOGENESIS OF KIDNEY IN SHEEP (Ovis aries)(SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA, 2017-08) DURGA PRASAD, DANGETI V.V.N; NAGAMALLESWARI, YAMANI(MAJOR); RAJU, N.K.B.; RAGHUNATH, MABSTRACT: The study was carried out in 45 embryos and foetuses of local Nellore sheep from 20 days to 150 days of gestation to explicate the development of various structures in the kidney. At 20 days (0.7cm CRL) of embryo, the mesonephros located lateral to the testis and occupied larger part of the coelomic cavity. In group I (39.5 days) to group III (150 days) the dorsal surface of both the metanephric kidneys was in contact with psoas major muscle. The metanphric kidneys, in all age groups were varying in colour from light to dark brown. In 20 day (0.7cm CRL) old sheep embryo the pronephros was placed on either side of the dorsal aorta which was surrounded by undifferentiated mesenchymal cells. The pronephros consisted of only one giant glomerulus of 225±1.3μm in size. At 24 days (1.1cm CRL) degenerative changes were noticed in glomerular network due to which vacuolation was noticed between the tuft of glomerulus. In 20 day (0.7cm CRL) old embryos the mesonephric parenchyma was densely packed with tubules, migrating angioblasts and differentiating glomerulus. At 24 days (1.1cm CRL) the mesonephric glomerulus surrounding visceral and parietal layers were demarcated at this age. In 27 days (1.7cm CRL) the manifestation of macula densa of DCT, Juxtaglomerular cells of afferent arteriole and mesengial cells at vascular pole of Bowman’s capsule was observed. At 49 days (7cm CRL) of gestation glomerulus shrinkage was noticed indicating the degeneration process initiated in mesonephros. The ureteric bud of metanephros was formed by evagination of the caudal part of the mesonephric duct in sheep embryo at 20 days of gestation (0.7cm CRL). At 44 days (5cm CRL) of gestation the number of the renal corpuscles were increased and distributed towards periphery from the pelvis. Demarcation between proximal and distal tubules was noticed. Major and minor calyces were apparent at 57 to 60 days of gestation and increased quantity of collagen at the sinus around the major and minor calyces. Loop of Henle was first appeared at 83.5 days, which were well established in juxta medullary nephrons as descending and ascending limbs. In group III the typical cortex and medulla was differentiated as adult kidney and renal corpuscles were still under differentiating stages in the cortical region by 101 days. Papillary ducts were lined by stratified cuboidal epithelium minor calyx was lined by transitional epithelium like adult kidney and smooth muscle were also noticed in the wall of the calyx minor in 115 days of gestation. By 120 days Juxta glomerular cells exhibited the cytoplasmic granules. In group III at 101 days (26cm CRL) the capsule and tubules showed mild PAS positive reaction and the cytoplasm of collecting ducts showed intense PAS positive indicating the neutral mucopolysccharides in the collecting ducts. In group I to group III the renal corpuscles, tubules and collecting ducts showed negative reaction for both acid and alkaline phosphatasesThesisItem Open Access DEVELOPMENTAL STUDIES ON PANCREAS IN SHEEP FOETUS (Ovis aries)(SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA, 2016-12) SWETHA, NANDAGARI; NAGAMALLESWARI, YAMANI(MAJOR); RAJU, N.K.B.; HARIKRISHNA, N.V.VABSTRACT: The present study was conducted on the prenatal development of pancreas in sheep foetuses of age 37 to 122 days of gestation. Morphologically pancreas was undifferentiated from 37 days (0.7CRL) to 43 days (3.7CRL) old foetuses. At 38 days of gestation (CRL- 1.5 Cm) histologically dorsal pancreatic lobe was present towards the duodenum and the ventral lobe towards liver. In the pancreatic primordia, ductules were also present, lined by single to double layered cuboidal cells by leaving a wide lumen and few endocrine cells were differentiated in 44 days. During 51 to 52 days of gestation, round bulb like acini without lumen were closely adhered to the ductules. At 55 days, the developing lobules were located towards the periphery of the pancreatic parenchyma. In 61 days, initiation of the interlobular septa with collagen and reticular fibres and islet groups with blood cells were observed in the parenchyma. Nerve fibres were evidently surrounding the forming lobules and also in the interlobular connective tissue in 74 days of foetal pancreas. In 80-84 days , duct system was clearly noticed in the developing exocrine part, intralobular and interlobular ducts lined by cuboidal cells. During 87 to 90 days, developing islets of varying sizes were noticed at the periphery of lobules as well as in the interlobular connective tissue and were separated from the acini by a thin connective tissue capsule At 90 days the apical surface of acinar cells contained cytoplasmic granules and centroacinar cells were distinctly appeared in some lobules with euchromatic nucleus. At 122 days of gestation, lobules were more obvious divided by a thick connective tissue septa and cluster of endocrine cells were surrounded by blood islands which might be the future sinusoids. Histochemical studies revealed that the acinar cells in the lobule expressed moderate reaction for some neutral mucopolysaccharides. Some of the differentiated acini at periphery of the lobule expressed the reaction in 80 to 90 days. Few cells present at the terminal portions of exocrine acini of pancreas were immunologically reactive to insulin antibody. These cells appeared to be beta (β) cells at 90 days. In 122 days immunologically reacted cells against insulin antibody were present between exocrine portions within the lobule.ThesisItem Open Access STUDIES ON THE PRENATAL DEVELOPMENT OF TESTIS IN SHEEP (Ovis aries)(SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA, 2016-12) BASAVAIAH, MAACHEPALLI; NAGAMALLESWARI, YAMANI(MAJOR); RAJU, N.K.B; RAGHUNATH, MABSTRACT: The present study was undertaken to elucidate the developmental changes in the testis. The study was conducted on 38 embryos and foetuses of sheep collected from local abattoirs from 37 to 122 days (0.7 to 41 cm CRL) were collected and divided into three age groups basing on gestation periods. In group I, at 42 days of gestation, testes were located in between the metanephric kidneys medially and mesonephros laterally in the lumbar region and scrotal bud was first observed in the inguinal region. At 59 days of gestation, the testes were located at caudal pole of kidney. At 94 days of age, the descent of testes into the scrotum was completed. At 122 days of gestation, testes were located in the scrotal sac. At 44 days of gestation, testes were oblong in shape but testes were changed to oval at 46 days of foetal life later became elongated at 60 days of gestation. The genital ridge was first observed between the mesonephoros and primitive gut in 37 day old sheep foetus. At 39 days of gestation, the gonadal anlages protruded into the coelomic cavity as paired oval-shaped structures on either side of the dorsal mesentery of the hindgut medial to the mesonephros. At 44 days of gestation, mesenchymal cells beneath the germinal epithelium were transformed to tunica albugenia. Sex cords were first appeared at 44 days foetal testes. The dark small cells were modified to form Sertoli cells and were first observed at 46 days of gestation. At 69 days, the lumenization was observed in more number of seminiferous tubules. At 94 days, very few tubules were closely adherent with the endothelial cells and formed blood testes barrier. At 46 days of foetal life, the interstitial endocrine cells gradually modified to form isolated Leydig cells. At 44 days of gestation, the central area of the testis was devoided of sex cords and tailored as mediastinum testis. In group III, the mediastinum consisted of densily packed collagen and reticular fibres in between the rete tubules. At 73 days of gestation, the density of cell clusters in the area of mediastinum testes was increased. Vacuolation was observed in the central area of cell clusters resulted in the initiation of the lumen formation in rete testis. Histochemical studies of testes revealed that in group III at 122 days of gestation, intense positive reaction in the capsule, basement membrane of seminiferous tubules and blood capillaries was identified for mucopolysaccharides. Intense positive reaction was identified in the capsule, basement membrane of seminiferous tubules and blood capillaries for glycogen at 122 days. In group II and III mild reaction for lipids in the capsule was recorded.ThesisItem Open Access MICROANATOMICAL STUDIES ON THE TESTIS AND PINEAL GLAND OF ADULT RAM (Ovis aries)(SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA, 2015-10) GOPI KRISHNA, B; RAJU, N.K.B(MAJOR); JAGAPATHI RAMAYYA, P; DHANA LAKSHMI, NABSTRACT : The present work on microanatomical studies on the testis and pineal gland of adult ram (Ovis aries) was conducted on adult healthy rams. The testis was enclosed by a capsule the tunica albuginea and a visceral tunica vaginalis. The tunica albuginea was composed of very dense collagen and reticular fibres and several blood capillaries noticed at deeper portion of the tunica albuginea. The mean thickness of the tunica albuginea was 558.37 ± 26.63 μm. Centrally located mediastinum testis with collagen fibres predominantly. The convoluted seminiferous tubules were lined by spermatogenic epithelium which was stratified showed spermatogonia, spermatocytes, spermatids, spermatozoa and Sertoli cells. The seminiferous tubules were separated from each other by interstitial tissue. The mean diameter of the seminiferous tubules was 128.45 ± 3.15 μm. The spermatogenic cells located in groups between the Sertoli cells, in three to seven layers. Three types of spermatogonia were observed viz., A-type, Intermediate type and B-type spermatogonia. The A-type spermatogonia were largest and had a round nucleus with fine chromatin granules. The intermediate type spermatogonia had a spherical nucleus with centrally distributed chromatin. The B-type spermatogonia consisted of small and spherical nuclei with thick chromatin concentration. The primary spermatocytes had spherical shaped darker nuclei with lightly stained cytoplasm. The secondary spermatocytes were rounded in shape with centrally placed spherical nucleus and scanty cytoplasm. The spermatids were smallest cells of the spermatogenic epithelium. They were round or elongated possessed spherical or elongated nuclei with thin peripheral cytoplasmic rim. The Sertoli cells were located in between the spermatogenic cells and they were elongated tall columnar type rested on the basement membrane with indistinct cell boundaries and had large deeply indented ellposidal nucleus with homogenous nucleoplasm. The Leydig cells were located in the meshes of interstitial connective tissue in single or groups with a large centrally placed spherical nucleus and granular cytoplasm. The capsule of testis, basement membrane of the seminiferous tubules and maturing spermatids showed strong positive reaction for neutral and acid mucopolysaccaharides and very weak reaction for lipids. Strong reaction for lipids was noticed in spermatogonia and the primary spermatocytes and moderate reaction for lipids in spermatids and Leydig cells. The spermatogonia, primary and secondary spermatocytes and Sertoli cells showed weak reaction for PAS and wall of blood vessels showed moderately positive reaction for PAS. The Leydig cells showed strong reaction for glycogen. The acid phosphatase activity was strong in the basement membrane and spermatogenic cells and moderate to weak in Leydig cells. Alkaline phosphatase activity was mild in seminiferous tubules and almost negative in the interstitial tissue. The pineal gland in adult ram was highly vascularised and innervated by nerve fibres and had a very thin capsule. Capsule was made up of collagen and reticular fibres with indistinct lobulation. The parenchyma consisted of two types of cells viz., pinealocytes and interstitial cells scattered throughout the interstitial tissue. The interstitial tissue was made up of reticular and collagen fibres observed in the vicinity of blood vessels. Pinealocytes were the thickly populated at the periphery and arranged in cords in the centre portion of the gland. The pinealocytes showed oval or round nucleus and possessed numerous cytoplasmic processes. Ultrastructurally, the pinealocytes were categorised into light and dark types. The light pinealocytes had round to oval nucleus with one (or) more nucleoli with chromatin material accumulate as smaller clumps attached to the nuclear membrane. Dark pinealocytes were sparse and showed pear shaped nuclei with irregular outer surfaces with evenly distributed chromatin material. The interstitial cells were neuroglial cells categorised into three types. Type-1 cells were large, oval (or) round with one (or) two processes and distributed as small groups showed smooth surface and chromatin material was aggregated in small irregular clumps towards the nuclear membrane. Type-2 cells had large, elongated (or) oval nuclei. Type-3 cells were smaller and showed numerous fine processes mainly associated with blood vessels and had large indented nuclei. PAS activity was mild in capsule of the pineal gland and interstitial cells, strong pinealocytes and intense in blood vessels. The interstitial cells showed moderate to strong reaction for acid mucopolysaccaharides in their cytoplasm. The pinealocytes and the interstitial cells showed very mild reaction for alkaline phosphatase and intense acid phosphatase activity. The varied sizes of corpora arenacea were observed in the pineal parenchyma.ThesisItem Open Access DEVELOPMENTAL STUDIES ON PANCREAS IN SHEEP FOETUS (Ovis aries)(SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI – 517 502. (A.P) INDIA, 2016-12) SWETHA, NANDAGARI; NAGAMALLESWARI, YAMANI (MAJOR); RAJU, N. K. B; HARIKRISHNA, N.V.VABSTRACT: The present study was conducted on the prenatal development of pancreas in sheep foetuses of age 37 to 122 days of gestation. Morphologically pancreas was undifferentiated from 37 days (0.7CRL) to 43 days (3.7CRL) old foetuses. At 38 days of gestation (CRL- 1.5 Cm) histologically dorsal pancreatic lobe was present towards the duodenum and the ventral lobe towards liver. In the pancreatic primordia, ductules were also present, lined by single to double layered cuboidal cells by leaving a wide lumen and few endocrine cells were differentiated in 44 days. During 51 to 52 days of gestation, round bulb like acini without lumen were closely adhered to the ductules. At 55 days, the developing lobules were located towards the periphery of the pancreatic parenchyma. In 61 days, initiation of the interlobular septa with collagen and reticular fibres and islet groups with blood cells were observed in the parenchyma. Nerve fibres were evidently surrounding the forming lobules and also in the interlobular connective tissue in 74 days of foetal pancreas. In 80-84 days , duct system was clearly noticed in the developing exocrine part, intralobular and interlobular ducts lined by cuboidal cells. During 87 to 90 days, developing islets of varying sizes were noticed at the periphery of lobules as well as in the interlobular connective tissue and were separated from the acini by a thin connective tissue capsule At 90 days the apical surface of acinar cells contained cytoplasmic granules and centroacinar cells were distinctly appeared in some lobules with euchromatic nucleus. At 122 days of gestation, lobules were more obvious divided by a thick connective tissue septa and cluster of endocrine cells were surrounded by blood islands which might be the future sinusoids. Histochemical studies revealed that the acinar cells in the lobule expressed moderate reaction for some neutral mucopolysaccharides. Some of the differentiated acini at periphery of the lobule expressed the reaction in 80 to 90 days. Few cells present at the terminal portions of exocrine acini of pancreas were immunologically reactive to insulin antibody. These cells appeared to be beta (β) cells at 90 days. In 122 days immunologically reacted cells against insulin antibody were present between exocrine portions within the lobule.ThesisItem Open Access HISTOMORPHOLOGICAL STUDIES ON CEREBRAL AND CEREBELLAR CORTICES OF RATS EXPOSED TO METHYL MERCURY(SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI – 517 502. (A.P) INDIA, 2015-12) NAGENDRA REDDY, MOILLA; NAGAMALLESWARI, YAMANI (MAJOR)ABSTRACT: The present study was conducted on 36 adult male Sprague Dawley rats aged 6 weeks, which were randomly grouped into control (group I), 2.5ppm methyl mercury exposure (group II) and 5ppm methyl mercury exposure (group III). There was a significant increase in body weight of 5ppm group compared to 2.5ppm and control groups at 35 days post exposure. Mean brain weight was higher in 5ppm group at 14 days post exposure and 2.5ppm group at 35 days post exposure. The average length of brain was higher in both the treated groups when compared to control at 14 days post exposure.Histological study of motor and visual area of cerebral cortex revealed deranged cortical cell organization with reduced number and shrunken neurons in both the treatment groups at 14 days post exposure and further increased in 35 days of exposure. In the motor area Perineuronal space, haemorrhages in capillaries and vacuolation in neuropil were evident in 5ppm group at 35 days post exposure. Deranged neurofibrillar network was also observed. Astrogliosis was observed in all the treated groups but more evident in 2.5ppm group at 35 days post exposure. The visual cortex showed increased vascularity with hypertrophy of the capillaries in both the treated groups and was markedly visible in 5ppm group at 35 days post exposure compared to 14 days post exposure. Ruptured endothelial basement membrane was thrown in to capillary lumen, astrocytes invaded in to some capillaries, vacuolated external and internal pyramidal cells were more evident in 2.5ppm compared to 5ppm in 35 days than at 14 days post exposure. This might be one of the reasons for the disruption of blood brain barrier in low doses for long period of exposure.In the cerebellar cortex, the average thickness of molecular cell layer, granular cell layer, average number and size of Purkinje cells were reduced in both the treated groups in both the treatment periods. Many of the Purkinje cells lost their dendritic arborization at 14 days post exposure and were further intensified in 5ppm than in 2.5ppm group at 35 days post exposure. Purkinje cell shape was altered in both exposure periods in 5ppm group and loss of nucleoplasm and karyolysis in 2.5ppm at 35 days post exposure. In the granular layer, granule cells were disoriented and few altered in their shape in both the treatment groups at 35 days post exposure. Vacuolation was predominant in 5ppm group at 14 and 35 days post exposures and also disorganized afferent and efferent fibers and loss of basket around the Purkinje cells were observed. Autometallographic analysis revealed the accumulations of mercury particles in neuropil, neuronal cell bodies and capillaries of motor and visual areas of cerebral cortex and also observed at the capillary walls. Molecular, Purkinje and granular layers showed the presence of mercury particles in the neuropil, Purkinje cells and granular cells. Sub cortical white matter was also presented with mercury localization in both the treatments with various intensities.