The endocrine system in humans consists of the glands and organs that make hormones and release them directly into the blood so they can travel to tissues and organs all over the body. The hormones released by the endocrine system control many important functions in the body, including growth and development, metabolism, and reproduction. They act as a messenger system, controlling the hormones released by internal glands into the circulatory system, regulating distant target organs. In humans the major endocrine glands are the thyroid, parathyroid, pituitary, pineal, testes, ovaries and adrenals.

In this series of drawings Mat Brown characterises the endocrine system as a single pink wormlike creature interacting with its human host, sometimes cooperatively and sometimes antagonistically. In this way he draws attention to the ways in which our bodies can respond internally and externally to the signals it receives.