The thymus, which is the largest lymphoid organ found in mammals, is located between the heart and the sternum. It functions as a site for t-cell production, because t-cells are white blood cells that are responsible for fighting off infections.
Additionally, it also produces hormones involved with positive emotional response during times of stress or illness.
Do you know which lymphoid organ is primarily active during the early years of life?
You may not know that although weakened after childhood, the thymus regenerates later in life to produce different forms of t-cells.
Here some points are discussed-
1. The thymus regenerates after childhood.
The thymus is a lymphoid organ that is formed during childhood. If you were to observe a child, you would notice that the area around their sternum has a ridge of tissue which gives the child a mature appearance.
This is the thymus which produces hormones (thyroid hormones especially) and various types of white blood cells. The thymus is really important in early life, because it helps us fight infections, and produce growth hormones that help us build bone and muscle tissue.
But this is not all. The thymus also plays an important role in repairing or replacing the body’s immune system after injury or illness.
However after childhood, the thymus begins to shrink, until it becomes almost completely non-functional. At this time, the immune system relies on other means to fight off infections and repair damaged tissue.
2. The thymus regenerates later in life.
The thymus does not stay in a dormant state for too long. After adulthood, it begins to regrow, and during this time the body’s immune system is slowly restored, so that it can fight off infections and repair damaged tissue in the same way that it did during youth.
3. Regeneration of the thymus is an ongoing process.
Many studies have shown that various parts of the thymus regenerate continually over an adult’s life span, rather than stopping and starting all at once as previously thought. The thymus regenerates to some degree at various points throughout adulthood.
4. The thymus has a number of functions in adulthood.
Even though the thymus is greatly reduced during adulthood, that doesn’t mean that it has no importance to the immune system. In fact, studies have shown that the thymus actually produces important immune cells like B cells and t-cells, which are responsible for memory responses and cellular immunity.
In addition, t-cells produced in the thymus also aid in tissue repair or replacement. Evidence also suggests that thymic rejuvenation may allow the body to produce new t-cells as needed if the immune system were to be weakened.
5. The thymus is not limited to humans.
Many other species of vertebrates have a thymus including salamanders, turtles, snakes and lizards, and even some fish species. The specific tasks that the thymus performs in these species are different from what humans do, but it is believed that the principle remains the same for all of these living organisms.
6. There are many kinds of cells in the thymus.
There are three main kinds of cells within the thymus: B-cells, T-cells, and dendritic cells.
B-cells in the thymus make up about 20-30% of all cells, and are responsible for producing antibodies. Antibodies are proteins that promote the destruction of foreign substances, like bacteria or viruses. T-cells are also found in the thymus and make up about 70% of all cells. They mature into T-cells that aid the immune system through specific tasks such as cellular immunity or memory responses.
Finally, dendritic cells make up another 10% of all thymic cells. They help B-cells produce antibodies, and also stimulate further immune response after an initial response has been initiated by other means.
7. The thymus is located in the upper chest area.
The thymus is a soft, but firm organ that is located between the heart and the sternum (the breastbone). It is an organ that forms during fetal development and continues to function until adulthood. It is also a part of the bone, which makes it visible on an X-ray.
8. The thymus forms during fetal development.
During fetal development, the thymus develops from embryonic cells in the body or from underdeveloped tissue in the heart or the kidneys areas. The thymus starts as a single bud-like structure, then divides into multiple buds over several weeks until it reaches its adult size. It then continues to divide, forming three layers: cortex (outer structure), medulla (inner structure) and crypts (tissue that produces T-cells).
