Spinal cord is the major nerve tract of vertebrates, extending from the brain through the vertebral canal. Primordium, the neural tube was initially with thick lateral walls having three layers: inner germinal/ependymal layer, middle mantle layer forming the gray matter and outer marginal layer forming white matter. It presented a diamond-shaped lumen with a sulcus limitans, alar, basal, roof and floor plates and limiting membranes. Gray matter of the cord occupies the central region of spinal cord and in amniotes has in cross section, the well-known &lsquo;H&rsquo; or butterfly-like shape. The white matter forms a thick peripheral zone of the cord and is divided by the gray columns into dorsal, lateral and ventral funiculi. There are three coumns for the gray matter, viz. the dorsal, ventral and lateral horns, with ventral ones being wider at the enlargements of the cord. Lateral horn appears only at thoracic, anterior lumbar and middle sacral levels. The layers of gray matter were laminae I to X. Lamina I or marginal zone capped the dorsal horn. Lamina II represented substantia gelatinosa and covered the dorsal horn, beneath marginal zone. Lamina III was an area with loosely arranged larger cells, entering the substantia gelatinosa. Lamina IV was a poorly defined cell column with nucleus proprius. Lamina V was a broad zone extending across the cervix of the dorsal horn; had spinal reticular nucleus and reticular processes. The region showed small to medium-sized cells which were most numerous in the zone between the ventral part of the dorsal horn and the lateral funiculus of white matter. Lamina VI was broad with unclear boundaries, related medially to central canal. It had compact medial and less compact lateral zones. Lamina VII shows the intermediate gray matter, with intermediolateral and intermediomedial nuclei, cervical nucleus of Stilling and Clark&rsquo;s column. Lamina VIII had cells of small and medium size and was not sharply distinguished from lamina VII. Lamina IX had alpha and gamma type of neurons, which were larger at enlargements. Ventral horn had lateral and medial nuclear groups of multipolar neurons. Medial nuclear groups were seen in all regions and lateral groups only at enlargements. Medial nuclear group had dorsomedial and ventromedial nuclei; whereas the smaller lateral nuclear group had dorsolateral and ventrolateral nuclei. In addition, the enlargements also had central and retrodorsolateral nuclei. Lamina X was seen around the central canal. Laminae varied in cell size and thickness between regions of the cord. Development of laminae and nuclei of spinal gray in fetuses corresponded to the progressive growth of muscles and skeleton. All the ten laminae were together present in the spinal gray matter by the end of gestation.

Developmental Anatomy of Gray Matter of Spinal Cord in Animals with Special Reference to Prenatal Goat: A Review

Background: The digestive system is responsible for the intake, conversion and absorption of nutrients and the elimination of wastes from the body in order to provide the necessary energy for the continuation of vitality and functions. The aim of this study was to examine the glandular stomach of the Chinese goose (Anser cygnoides) by histological, histochemical and scanning electron microscopic methods. 
 
Methods: The glandular stomachs of 12 (6 males and 6 females) healthy adult Chinese geese (Anser cygnoides) were used in the study. The tissues taken were subjected to routine histological procedures.&nbsp; 
 
Result: Gross anatomically, it was seen that the Proventriculus was a fusiform or spindle-shaped organ, extending along the median plane between the esophagus and the muscular stomach. Scanning electron microscopic (SEM) observations revealed that the glandular stomach surface of Chinese goose (Anser cygnoides) contained many mucosal folds. Parallel grooves and proventricular gland openings were observed between these folds. Histologically, it was observed that the glandular stomach wall of Chinese goose (Anser cygnoides) consisted of four layers: tunica mucosa, submucosa, tunica muscularis and tunica serosa. The tunica mucosa was observed to have lamina epithelialis, lamina propria and lamina muscularis sublayers. Single layer prismatic cells secreting mucus were found in the lamina epithelialis layer. These cells showed local Alcian Blue (AB) pH:2,5 positive reaction. Lamina muscularis consisted of longitudinal smooth muscle fiber bundles. Compound, branched tubular glands were observed in the submucosal layer. Again, a regional AB positive reaction was observed in the lumen-facing parts of the tubular glands. Periodic acid Schiff (PAS) positive reaction was noted in the basal parts of the tubular glands. In Gordon-Sweet (GS) staining method, reticular threads easily distinguished in all areas where connective tissue present.

Gross Anatomical, Histological, Histochemical and Scanning Electron Microscopic Examination of Glandular Stomach of Chinese Goose (Anser cygnoides)

<div>Background: To have a better understanding of the lympho glandular complexes (LGC) along with the histoarchitecture of large intestine and associated M cells, the proposed study have been undertaken. 
 
Methods: Present study was conducted on 12 (twelve) numbers of apparently healthy weaned crossbred piglets of 3 to 4 months irrespective of sex. After humane sacrifice of the animals with the approval of institutional animal ethics committee, the representative tissue samples were collected preserved, processed and stained as per standard methods of Luna (1968).&nbsp;&nbsp; 
 
Result: Columnar cells predominated the follicle associated epithelium (FAE) and the crypts. M cells were recorded in the follicle associated epithelium as well as in lower crypt epithelium in toluidine blue stained ultra thin sections. M cells were observed with intraepithelial lymphocyte and basally placed euchromatic nucleus. In the colon and rectum of crossbred pigs the lympho glandular complex (LGC) typically consisted of a pore like depression on surface epithelium from which extensions of mucosal glands passed through the circular gap into lamina muscularis mucosae. The lymphatic aggregation of LGC in the lamina propria and tunica submucosa showed three distinct zone viz. follicle, interfollicular area and dome area and distinct FAE could be appreciated. The epithelium lining the solitary lymphatic nodule (SLN) showed (Periodic acid-Schiff) PAS positive reaction. The mucous substance showed strong reaction in the gland in LGC and the FAE epithelium the number of goblet was less. The LGC was formed by aggregation of lymphoid follicles with invagination of crypt gland inside the follicle in the tunica sub mucosa. The follicle associated epithelium devoid of goblet cells were observed on the LGC with interspersed of diffuse migrating lymphocytes in the lamina propria. In the LGC, secondary follicle with interfollicular area was appreciated. In mesenteric lymph node the secondary follicles with inner germinal centre and outer corona could be seen in cortico medullary area. Meshwork of reticular fibers was abundantly present around the crypts in the lamina propria and in the pore like depression of LGC and around the secondary follicle. Collagen fibers could be seen surrounding the LGC and glands. Scanty collagen fibres were observed in the inter-follicular glands. Innervations of nerve fibre was observed around the lymphoid follicle and penetrating the LGC. The mucosal glands were PAS positive.</div>

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Histoarchitecture of Large Intestine and Lympho Glandular Complex of Pig

<div>Background: The study on Gut Associated Lymphoid Tissue (GALT) of Pati duck of Assam is of great value in regard to normal academic and bio-medical research aspects. The aim of the study was to evaluate the gross, histomorphological and scanning electronic microscopic examination of gut-associated lymphoid tissue of the intestine of Pati duck at different age group. 
 
Methods: For this study, forty five Pati ducks were divided into five groups depending on its age viz., 1st week, 4th week, 16th week, 24th week and 42nd weeks old. The pieces of gut having lymphoid tissue or Peyer&rsquo;s patches were collected immediately after slaughter. These samples were fixed in 10% neutral buffered formalin solution and were processed as per the standard technique of procedure (<a href="#luna_1968">Luna, 1968</a>). The paraffin blocks were sectioned in Shandon Finesse microtome at 5 &micro;m thickness and the sections were stained with Mayer&rsquo;s Haematoxylin and Eosin staining technique for Cellular details, Van Gieson&rsquo;s method for collagen fibres, Gomori&rsquo;s method for reticular fibres, Hart&rsquo;s method for elastic fibres and Bielchowsky&rsquo;s method for axis cylinder and dendrites as per the method of <a href="#luna_1968">Luna (1968)</a>.&nbsp; 
 
Result: Gut-associated lymphoid tissue was found in the duodenum, jejunum, ileum, caecum and the terminal part of the rectum in all the age group of Pati duck. The lymphoid compartment of the gut-associated lymphoid tissue in duck included a follicular structure, dome, follicle associated epithelia and interfollicular area. Lamina propria of jejunum was heavily infiltrated with diffuse lymphatic tissue in the 16th, 24th and 42nd week of age of Pati duck. The scattered and diffuse lymphatic infiltration occurred in all age groups. The lamina propria of the colorectum revealed an extensive network of reticular fibre with diffused lymphatic tissue in all the age group of duck. In Scanning Electron Microscope, the lumen of the jejunum was covered by finger-like villi with numerous opening of goblet cells. The lymphoid follicle of Lamina propria contains numerous lymphocytes along with connective tissue fibres.&nbsp;</div>

Gross, Histomorphological and Scanning Electronic Microscopic Studies on Gut Associated Lymphoid Tissue of Intestine of Pati Duck (Anas platyrhynchos domesticus) of Assam

The objective of this study was to investigate the morphological features of the proventriculus of African ostrich (Struthio camelus). The location, appearance, and histological characteristics of the proventriculus were observed on postnatal day 90. The entire proventriculus had the appearance of a distensible sac; and &nbsp;exhibited a large number of glands. Under light microscope, the proventriculus wall was composed of &nbsp;mucosa, submucosa, muscular layer and adventitia. The mucosa was further divided into the lamina epithelialis, lamina propria, and muscularis mucosae. The submucosa was relatively thick and contained &nbsp;compound tubular glands having oxynticopeptic cells, mucous cells, and endocrine cells. These features of the proventriculus are possibly related to the dietary habits of the African ostrich, and they imply that this specie has a strong ability to digest and absorb food.

Morphology of the proventriculus of African ostrich

<div style="text-align: justify;">A study was undertaken to appraise the macro anatomical development of fore stomach of foetal goat. For this study 36 foeti/ embryos were divided into three groups viz. Group I (0-50 days of gestation), II (51-100 days of gestation) and III (101 days of gestation to till term) having 12 foeti in each group. All the four compartments of the goat stomach were clearly discernible by 38 days of gestation. Under stereozoom microscope, by 34 days of gestation the digestive tube showed three dilatations and two constrictions. Quadrilateral rumen was placed on left side of the median plane between 8thrib to 1st lumbar vertebra at term. Except cranio- dorsal coronary groove all other ruminal grooves were discernible before birth. Large dorsal and small ventral sacs were noticed at 46 days of gestation. Fine ruminal papillae were noticed from 90 days onwards. The reticulum became cranial most compartment of stomach after 50 days. Pear-shaped reticulum was placed on left side of the abdominal cavity in group I and pushed to just left of the median plane after 50 days of gestation. Near term (134 days), it was extended between 7th to 9th rib. Internally the reticulum showed honey comb-like folds at 107 days of intra uterine life. Originally the circular omasum was placed on the left of median plane and from 55 days onwards gradually shifted to the right side. During gestation, a cranial ascent of the omasum was noticed with its placement between 9th -11th ribs at term. &nbsp;Under stereozoom microscope, leaf-like omasal lamina was observed from 38 days of gestation. Primary, secondary, tertiary and quarterly laminae were observed on 38, 51, 55 and 87 days of gestation, respectively. Statistical analysis of the data revealed that biometrical parameters of fore stomach increased significantly with advancement of age and were highly significantly correlated with each other.</div>

Gestational variations in the macro anatomy of the fore stomach of goat&nbsp;(Capra hircus)

The process of follicular development and features of morphological changes are essential to understand the factors involved during folliculogenesis and to improve fertility in buffalo. Hence the objective of the present study was to report ultrastructural features of atretic ovarian follicles in buffalo. In the early stage of atresia, the involvement of mitochondria was observed and whereas in the later stages of atresia, involvement of macrophages were observed. The granulosa cells of buffalo atretic tertiary follicles were observed to contain undulation of the nuclear membrane, crescent formation of the pyknotic nuclei and loopiness and undulations of the basal lamina. These features are similar to the reports in other species. The involvement of mitochondria in the early stage of atresia suggested the probable role of a reactive oxygen free radical induced damage.

Ultrastructural features of atretic ovarian follicles in buffalo (Bubalus bubalis)

Irisin, a novel peptide, was first identified in skeletal muscle cells. It is an exercise protein that is secreted into the bloodstream, through which it reached the white adipose tissue, and interacted with an unknown receptor and cause fat destruction by converting the white adipose tissue to brown adipose tissue. The presence of irisin immunoreactivity in porcupine lung and tongue was studied. In lung, irisin immunoreactivity was found in type II pneumocytes, bronchus, bronchioles and blood vessel. Positive irisin immunostaining was also detected in the lamina epithelialis, striated muscle cells and serous glands in porcupine&rsquo;s tongue. The function of locally synthesized irisin is currently unknown. Therefore, further study is required to reveal the precise effect of irisin.

Immunohistochemical distribution of irisin in the lung&nbsp;and tongue of Porcupine (Hystrix cristata)

Histological studies were conducted on the tonsil of soft palate in six month-old male crossbred goats. The tonsil was located on the nasopharyngeal side of the soft palate. The tonsillar surface epithelium presented small folds and was lined by pseudostratified ciliated columnar epithelium in the rostral half and stratified squamous epithelium in the caudal part. The epithelium mounting over the lymphoid accumulation or follicle associated epithelium was modified into a lympho-epithelium and was disrupted and heavily infiltrated by lymphocytes. Distinct crypts were not seen. In the lamina propria, lymphoid tissue constituted only a small portion of the tonsil and only two to three nodules were seen per low power microscopic field. Most of the lymphoid nodules had germinal centers. The average diameter of the nodules was 131.97&plusmn;8.03 &micro;m. Loose irregular connective tissue, lymphoid tissue and glands comprised the propria submucosa. The tonsil of soft palate was not encapsulated.

Histological studies on the tonsil of soft palate in goats

<div style="text-align: justify;">The present investigation was conducted on the comparative anatomical study of vagina (sperm storage organ) of Pati and Chara-Chemballi ducks during laying periods. The vagina was collected immediately after death and anatomical studies were made on it. The vagina was a narrow muscular tube, sharply curved and was tightly bound by ligament. The length, width thickness and weight of vagina of Chara-Chemballi ducks were significantly (p&lt;0.01) higher than Pati duck. The lining epithelium consisted of pseudostratified columnar epithelial cells with few goblet cells. The mean height of lamina epithelialis mucosae of vagina of the present study was significantly (p&lt;0.01) higher in Chara-Chemballi duck (26.508&plusmn;0.298 &micro;m) than Pati duck (23.058&plusmn;0.330 &micro;m). A weak PAS positive reaction was noticed in the lining epithelium of vagina of Pati and Chara-Chembali ducks.</div>