Quick, point to your thymus gland.
If you pointed to the front of your upper chest, well done! The thymus gland sits just behind the upper part of the breastbone, between the tops of the lungs and in front of and above the heart. In newborns, the thymus gland may be 2.5 inches long and weigh 1 ounce, but it shrinks over time beginning in the first year of life.
If you pointed elsewhere or had no idea, don’t feel bad. For most people, the thymus is unfamiliar and so is its whereabouts. And, for good reason: in most adults, the thymus gland is a tiny gland that’s been largely replaced by fat. But it wasn’t always that way.
How does the thymus gland help the immune system?
During fetal development, infancy, and early childhood, the thymus gland is quite important for the developing immune system. That’s when the thymus produces a special type of immune cells called T-cells (named for the thymus gland).
T-cells are essential to healthy immune function because they can kill cells infected by bacteria or viruses. They also attack tumor cells and help regulate other parts of the immune system.
Do you actually need your thymus gland?
The answer to this question depends on whether you are a developing fetus, young child, or adult. For the fetus and young child it’s quite essential, as noted above.
But there’s been uncertainty regarding the role of the thymus gland among adults. One reason is that over time it becomes a shrunken vestige of its former self, weighing in at a fraction of an ounce and shrinking to just one inch.
In addition, adults seem to do just fine without a thymus gland if it needs to be removed as a treatment for certain diseases, such as cancerous or benign tumors. Along with medications, thymus removal (thymectomy) may be part of treatment for myasthenia gravis, an autoimmune disease that causes muscle weakness, droopy eyelids, and double vision. The thymus gland seems to be the source of abnormal immune cells that cause this disease.
