Health Library

Endocrine System

The endocrine system is made up of glands (located throughout the body), hormones (which are made and secreted by the glands into the bloodstream) and receptors in various target organs and tissues (which recognize and respond to the hormones). The endocrine system works to regulate a wide range of biological processes, such as control of blood sugar, growth and function of the reproductive systems, regulation of metabolism and brain and nervous system development. (Read about "Nervous System")

According to the American Medical Association, the endocrine system includes:

• Pituitary gland - located in the brain (Read about "The Brain"), the pituitary is sometimes called the "master gland" because it produces a variety of different hormones that influence both other endocrine glands as well as a number of bodily processes.
• Hypothalamus - located in the brain, this area also produces hormones that control the functions of various other endocrine glands.
• Pineal gland - located at the base of the brain, it produces the hormone melatonin.
• Thymus - located behind the breastbone, the thymus is a part of the immune system (Read about "The Immune System")
• Adrenal glands - there are two adrenal glands, one located on top of each of the kidneys. The adrenals secrete hormones that influence the body's metabolism, blood chemicals and body characteristics, as well as influence the part of the nervous system that is involved in the "fight or flight" response to stress. (Read about "Stress")
• Thyroid - a butterfly-shaped organ located in the neck, the thyroid produces hormones that affect metabolism, bone growth and other functions. (Read about "Thyroid")
• Parathyroids - surrounding the thyroid are four small glands called the parathyroids. (Read about "Parathyroid Glands") They produce parathyroid hormone, which helps control the amount of calcium in our bodies and how it is used. If the parathyroids don't balance the calcium in our bodies, this can cause problems such as bone loss (Read about "Osteoporosis") and kidney stones (Read about "Kidney Stones"), according to the American Academy of Family Physicians.
• Pancreas - located in the abdomen, the pancreas secretes hormones that help regulate the use of glucose by the body. The pancreas can also be considered a part of the digestive system. (Read about "Digestive System")
• Testes in men - secrete hormones that affect sexual development and functions. (Read about the testes in "Genital Health - Male")
• Ovaries in women - secrete hormones that affect sexual development and functions. (Read about "The Ovaries")

Because of the complexity of the endocrine system, a number of diseases and conditions can be traced to problems in this system. Problems with the endocrine system can be referred to an endocrinologist, or physician who specializes in the area. According to the Endocrine Society, endocrinologists can provide treatment for a variety of conditions including menopause, osteoporosis, cholesterol disorders, obesity, and infertility (Read about "Menopause" "Osteoporosis" "Cholesterol" "Obesity" "Infertility") as well as endocrine-related diseases including the following: