* Cell-mediated immunity: T cells directly attack and destroy infected cells or cancerous cells.
* Immune regulation: T cells help to regulate the immune response, preventing it from becoming overactive or attacking healthy tissues.
Here's a breakdown of the thymus gland's control over T cell development:
1. Production of immature T cells: The thymus produces immature T cells, which then migrate to the thymus's cortex.
2. Maturation and selection: Within the thymus, immature T cells undergo a process of maturation and selection. This process involves testing the T cells' ability to recognize foreign antigens (antigens are substances that trigger an immune response).
3. Elimination of self-reactive T cells: T cells that recognize self-antigens (antigens from the body's own tissues) are eliminated, preventing autoimmune diseases.
4. Release of mature T cells: Mature T cells that have passed the selection process are released into the bloodstream, where they circulate and protect the body from infection and disease.
In addition to controlling T cell development, the thymus gland also secretes hormones that:
* Promote T cell maturation: These hormones include thymosin, thymopoietin, and thymulin.
* Influence the immune response: These hormones help regulate the activity of other immune cells.
The thymus gland is most active during childhood and adolescence. After puberty, it gradually shrinks, but it continues to produce some T cells throughout life.
