Thymus

The thymus is a temporary organ, attaining its largest size at the time of puberty, when it ceases to grow and gradually decreases. During thymus development many cells migrate towards it, most of which are lymphocytes. The thymus divided into two distinct compartments, the outer cortex and the inner medulla, which are densely populated with lymphocytes. The main function of the thymus is to develop immature T-cells into immunocompetent T-cells.