This study was conducted to elucidate histoarchitectural and histochemical changes in thymus during development of chick embryo. In 6, 11 and 14 day old embryos, thymus was made up of epithelial cords. At 16th day of incubation it was faintly divided into lobules which on 18th day were well demarcated by connective tissue septae. On 18th day medulla was staining lightly with few Hassell's corpuscles. Demarcation between cortex and medulla became more distinct on 21st day of incubation. Acid phosphatase activity, in 18 and 21 day old embryos, was mild and scattered in the thymic follicles. In 18 day old embryo, uniformly scattered intense cholinesterase activity was observed in thymic follicles. Very weak activity of Adenosine tri-phosphatase was found in periphery of thymic follicles in 21 day old embryo. No activity of glucose-6-phosphatase, lipase, 5′-nucleotidase and alkaline phosphatase was found. Similarly lipids, mucopolysaccharides and Periodic Acid Schiff positive material was not found at any developmental stage of thymus in chick embryo.
Histology, histochemistry, development, thymus, chicken embryo
