A gland is an organ which produces and releases substances that perform a specific function in the body. There are two types of gland. Endocrine glands are ductless glands and release the substances that they make (hormones) directly into the bloodstream. These glands form part of the endocrine system and information on them is included in this website. There is another type of gland called an exocrine gland (e.g. sweat glands, lymph nodes). These are not considered part of the endocrine system as they do not produce hormones and they release their product through a duct. Information on these glands is not included on this website.
Endocrine glands, such as the pancreas and thyroid gland, use the bloodstream to monitor the body’s internal environment and to communicate with each other through substances called hormones, which are released into the bloodstream.
The adrenal glands are small structures attached to the top of each kidney. The human body has two adrenal glands that release chemicals called hormones into the bloodstream. These hormones affect many parts of the human body.