Thymic Medullary Epithelial Cells (Body Picture Showers)

In the middle of the thymus

Your thymus is a small organ in your chest where T cells are trained. Its middle part is called the medulla.

In the medulla live medullary epithelial cells. Some of them curl up into round swirls that look like tiny onions.

Don't attack yourself!

T cells fight germs. But a T cell that attacked your own body would cause trouble.

• These cells show young T cells little pieces of proteins from all over your body, like a picture book of you.
• If a T cell reacts too strongly to a picture of your own body, it is removed, or changed into a peacekeeper cell that calms things down.
• The T cells that pass leave the thymus and go protect you.

Thymus picture quiz