Thymus Gland Lobule Detail
The darker purple area (cortex) contains many immature T -lymphocytes which will go through selection or "education" of lymphocytes. This is the first step in making T cells immunocompetent or able to distinguish self antigens from foreign antigens.
The lighter purple area (medulla) contains larger more mature T-lymphocytes going through the final selection stage.
Click on the green square to see the cellular detail.