Explain the structure are role of thymus in primary lymphoid organ.

Explanation

Thymus is most active during the neonatal and pre-adolescent periods.The thymus is a flat and bilobed organ located behind the sternun,above the heart.Each lobe of the thymus contains numerous lobules,separated from each other by connective tissue called septa.Each lobule is differentiate into an outer cortex and an inner medulla.Within each lobule,the inner medulla contains immature thymocytes and outer cortex has matured thymocytes.One of its main secretions is the hormone thymosin.It stimulates the T cell to become mature and immunocompetent .By the early teens,the thymus begins to atrophy and is replaced by adipose tissue.