The endocrine system consists of a series of glands throughout the body which secrete specific hormones. These hormones travel through the blood stream to their target organs to regulate organ function. The endocrine glands are regulated by a system called the hypothalamic-pituitary axis. The hypothalamus, a structure within the limbic system of the brain is the overall control centre. This secretes hormones which control the pituitary gland which is also located in the brain. The pituitary gland is often thought of as being the master gland since it, in turn secretes hormones which control the other endocrine glands. There are a number of endocrine glands including the pineal gland, the thyroid gland, the parathyroid glands, the thymus gland, the pancreas, the adrenal glands, the testes and the ovaries.
The adrenal glands are the most important in the stress response.