A gland is a special organ. It can be found in animals (and humans) and in plants. A gland makes a special substance. Very often, this is a hormone. If this substance is then put into the bloodstream, the gland is called endocrine gland. If the substance is released to somewhere else, the gland is called an exocrine gland.
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