part of has part contains process in taxon develops from T cell differentiation Gnathostomata <vertebrates> Homo sapiens anterior region of body endocrine system endocrine gland thymus check - a subtype of gland? not in GO. NCIT has thymus and thymus gland. EHDAA2 has ductless gland. hematopoietic system immune system thymus lymphoid tissue thymus epithelium endoderm-derived structure hemopoietic organ immune organ hemolymphoid system gland thymus primordium