Gland
Appearance
![](http://upload.wikimedia.org/wikipedia/commons/thumb/3/3c/Tepegua-2-glands.jpg/220px-Tepegua-2-glands.jpg)
A gland is a group of cells in the body which make substances such as hormones. They are in humans and other animals, and in plants.
- If the substance is put directly into the bloodstream, the gland is called endocrine gland.
- If the substance is carried by a duct, the gland is called an exocrine gland. Exocrine ducts empty outside the body, or into cavities inside the body.
Examples of glands in humans are:
- Sweat glands that produce sweat for perspiration.
- The pineal gland in the brain, which produces the hormone melatonin at night.