The thymus is a soft, triangular-shaped organ found in the chest posterior to the sternum. The thymus produces hormones called thymosins that help to train and develop T-lymphocytes during fetal development and childhood. The T-lymphocytes produced in the thymus go on to protect the body from pathogens throughout a person’s entire life. The thymus becomes inactive during puberty and is slowly replaced by adipose tissue throughout a person’s life.
Other Hormone Producing Organs
In addition to the glands of the endocrine system, many other non-glandular organs and tissues in the body produce hormones as well.
The anterior pituitary gland produces seven important hormones: human growth hormone (hGH), thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), adrenocorticotropic hormone (ACTH), and melanocyte-stimulating hormone (MSH). Each of these hormones targets specific receptors in the body to stimulate specific glands and tissues in the body. The thyroid gland, ovaries, testes, mammary glands, and the cortex of the adrenal glands are all stimulated by the hormones of the anterior pituitary, resulting in the pituitary gland being known as the “master gland” for its control of the endocrine system. More modern studies now show that, while still important, the anterior pituitary is subservient to the control of the hormones of the hypothalamus. Releasing hormones from the hypothalamus, such as thyrotropin-releasing hormone (TRH) and gonadotropic-releasing hormone (GnRH), stimulate the anterior pituitary to release TSH, FSH, and LH. Inhibiting hormones, such as growth hormone-inhibiting hormone (GHIH), prevent the secretion of hormones hGH and TSH.