Abstract

The thymus is the lymphoid organ of greatest importance. It is a structurally separated lobules through the tissue of the connective septa. That lobule has a cortex and a medulla in it. Many studies of this organ related to the histology of early fetuses are focused on animals. The present study focuses on certain features relating to the histogenesis of the thymus and adolescent fetuses. Materials and methods: Thirty human foetuses (19 males and 11 females) of different age groups ranging from 9th to 38th gestational week were procured from the Department of Anatomy of Chirayu Medical College & Hospital for the research work with due permission of the Medical Superintendent of the mentioned hospital and respective parents. Result: The histometric analysis of parenchyma (cortex and medulla) and connective tissue indicates that there was no significant variation in their ratio. These corpuscles were frequently seen in thymuses of the early gestational period which were called as Solid Hassall Corpuscle (SHC) and were located at the periphery of the medulla within the age group of the present study. Their size ranged from 25-35 μm with a mean of 31.166 μm. This epithelial capsule was separated from the central mass by a subcapsular space that gave a cyst like an appearance hence named primary cystic Hassall’s corpuscle (CHC I). Their size varied from 35-70 μm with a mean of 52.177 μm thickness Externally the whole structure was surrounded by an epithelial capsule as found in CHC I, hence named as secondary cystic corpuscles (CHC II). They were mainly observed in the central core of the medulla. Their size ranged from 50-100 μm with a mean of 74.185 μm thickness late stages were noticed. Conclusion: Thymus is responsible for the provision of the T-lymphocytes to the whole body in newborns and children until puberty. For this reason it is important to know the histology of the gland at different ages.

Description