(thymus) A specialized organ of the immune system located in the upper-middle chest where T cells mature.

(thymus) An organ that is part of the lymphatic system, in which T lymphocytes grow and multiply. The thymus is in the chest behind the breastbone.

(thymus) Corticomedullary organ, each instance of which is some lymphoid organ consisting of two pyramidal lobes located in some anterior superior mediastinum, anterior to some heart and posterior to some sternum.

(thymus) Single, unpaired primary lymphoid organ situated in the mediastinum; it is necessary for normal development of immunologic function early in life but by puberty it begins to involute and much of the tissue is replaced by fat.

A bi-lobed organ surrounded by a connective tissue capsule. It is located in the upper anterior portion of the chest, behind the sternum. It is composed predominantly of lymphocytes and fewer epithelial cells. Connective tissue septa separate the lobes into lobules. The lobules contain an outer portion (cortical zone) which is rich in lymphocytes and an inner portion (medullary zone) which is rich in epithelial cells. It is an organ essential for the development of the immune system. Its function is the maturation of the progenitor lymphoid cells to thymocytes and subsequently to mature T-cells. It reaches its greatest weight at puberty and subsequently begins to involute.

A primary lymphoid organ generally located in the mediastinum near the thoracic inlet and/or along lateral aspects of the neck.

A single, unpaired primary lymphoid organ situated in the MEDIASTINUM, extending superiorly into the neck to the lower edge of the THYROID GLAND and inferiorly to the fourth costal cartilage. It is necessary for normal development of immunologic function early in life. By puberty, it begins to involute and much of the tissue is replaced by fat.

Thymus, pyramid-shaped lymphoid organ that, in humans, is immediately beneath the breastbone at the level of the heart. The organ is called thymus because its shape resembles that of a thyme leaf. Unlike most other lymphoid structures, the thymus grows rapidly and attains its greatest size...