An adrenal gland is located in close proximity to each kidney. Each adrenal is composed of a cortex and a medulla, the cortex being derived from mesodermal tissue, the medulla migrating neural crest tissue. The cortex secretes a host of steroid hormones. The adrenal medulla secretes two types of amine hormones. The cortex responds to chemical stimulation. The medulla responds to nerve impulses. Being derived from neural crest tissue, the adrenal medulla can be viewed as part of the sympathetic nervous system.