What is thymus?
The thymus is a gland located behind the breastbone that plays a key role in immune function. It is where T-cells mature and learn to distinguish self from non-self. The thymus is largest in childhood and gradually shrinks with age.
Key Functions
- •T-cell maturation — trains immune cells
- •Immune competence — strong thymus = robust immune response
- •Stress sensitivity — chronic stress can impair thymic function
Why does Thymus matter?
The thymus matters because it trains T cells, a central part of the adaptive immune system. Immature T cells travel there from the bone marrow and learn to recognize foreign threats while ignoring the body's own tissues.
Cells that react too strongly against the self are mostly eliminated, which helps prevent autoimmune disease. The thymus is most active in childhood and gradually shrinks and is replaced by fat after puberty, a process called thymic involution, which is thought to contribute to weaker immune responses in older age.
What happens when the Thymus goes wrong?
When the thymus does not develop or work properly, T-cell immunity can be seriously impaired. In DiGeorge syndrome, the thymus may be small or absent, leading to vulnerability to infections in severe cases.
Thymus problems are also linked to autoimmunity. Myasthenia gravis is often associated with thymus abnormalities, including thymomas, which are tumors of the thymus. Surgical removal of the thymus is sometimes part of treatment. These conditions require diagnosis and management by medical specialists.
In ONDA Life
Part 5 aims to "restore the link between the sense of social safety and a powerful immune response" through the thymus. This is a practice image: chronic stress is associated with changes in immune function, but no practice has been shown to switch the thymus or immunity on through a felt sense of safety.