Endocrine system (or endocrine glands) is the collection of glands that secrete hormones directly into the bloodstream. These hormones regulate the body’s growth, metabolism (the way food is used for energy), and sexual development and function. The endocrine system is essential to an organism’s survival because it coordinates its actions by controlling hormone levels in the blood.
The main organs of the endocrine system are the pituitary gland, thyroid gland, parathyroid gland, adrenal gland, pineal gland, ovaries (in females), and testes (in males). The pancreas also secretes some hormones (such as insulin) into the blood. Hormones are chemical messengers that travel through the bloodstream to target tissues or organs and cause a specific response. For example, thyroid hormone helps to regulate metabolism; insulin regulates blood sugar levels; and adrenaline prepares the body for “fight or flight” in times of stress.
Endocrine disorders occur when there is a problem with one or more of the endocrine glands or with the hormones they secrete. Common endocrine disorders include diabetes mellitus, hypothyroidism, hyperthyroidism, Addison’s disease, Cushing’s syndrome, Graves’ disease, acromegaly, and gigantism. Treatment for endocrine disorders often involves medication to correct hormone levels or surgery to remove diseased glands.