THYMUS
- It is primary lymphatic organ (Produce T & B lymphocytes)
- Location: ventral part of the superior mediastinum, just behind the Sternum.
- It contains T-lymphocytes undergoing maturation.
- The thymus is the largest and most active during the neonatal (newborn) period
During the teenage years it begins to atrophy & involute.
After the age of around fifty, the thymus is almost completely replaced by an adipose tissue
Structure:
- Capsule - connective tissue.
- Trabeculae - Extensions from the capsule.
- Thymic Lobes: right & Left lobes
- Cortex: Contains immature T-cells (thymocytes) that undergo maturation & selection processes.
- Medulla: Contains mature T cells that have successfully passed through the processes.
- Criticomedullary junction: the transition zone between the cortex & medulla.
- Thymic (Hassal's) Corpuscles: structures found in the medulla.
- Their exact function is not fully understood.
- Thymic Arteries & veins.
Functions:
- Facilitate the maturation of T-cells
- Positive & Negative Selections
- ↳ to detect which T-cells can be send to ..