The Endocrine System

Organic Functional Groups

Zymogens

Tissues and Histology

Human Embryology

The Lymphatic System and Immunity

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.