March 20, 2025 | Hormones serve as messengers of sorts, traveling throughout the body to help it maintain some of its more complex processes, including growth, sexual function and reproduction. They can influence the function of the immune system, and even alter behavior. In response to a signal from the brain, hormones are secreted directly into the blood by the glands that produce and store them. The glands are known as the endocrine system, which produces and stores hormones, releasing them as needed. When the body needs these substances, the bloodstream carries the proper types of hormones to specific targets. These targets may be organs, tissues, or cells. To function normally, the body needs glands that work correctly, a blood supply that works well to move hormones to their target points, receptor places on the target cells for the hormones to do their work, and a system for controlling how hormones are produced and used.

March 20, 2025 | The endocrine system is made up of eight glands that secrete hormones. Scattered throughout the body, these glands are considered to be one single system because they have similar functions and mechanisms. The pituitary gland, for example, is no bigger than a pea and rests at the base of the brain. Made up of the anterior and posterior lobes, the pituitary gland produces the human growth hormone, which stimulates the growth of bone and other body tissues and plays a role in the body’s handling of nutrients and minerals. In addition, the pituitary secretes hormones that signal the reproductive organs to make sex hormones. The pituitary gland also controls ovulation and the menstrual cycle in women. The adrenal glands, located on top of each of the kidneys, secrete hormones like adrenaline, which affects your heart rate and sweating. They also secrete hormones that control the use of fats, proteins and carbohydrates in the body.

March 20, 2025 | The endocrine system includes the pineal gland, which is located in the middle of the brain, and the pancreas, situated in the abdomen. The pineal gland secretes melatonin, a hormone that may help regulate when you sleep at night and when you wake in the morning. The pancreas, meanwhile, serves two roles. As part of the endocrine system, it produces and secretes the hormones insulin and glucagon, which work together to maintain the proper level of sugar in the blood. The pancreas’ other job involves the production of enzymes that assist in digestion. Gonads, a third part of the endocrine system, are the main source of sex hormones. A woman’s gonads, known as ovaries, produce eggs and secrete the hormones estrogen and progesterone, which are involved in a woman’s menstrual cycle. The male gonads, or testes, secrete hormones called androgens, which control body programs that govern sexual development and physique.

March 20, 2025 | Once a hormone is secreted, it travels from the endocrine gland that produced it through the bloodstream to the target cells designed to receive its message. The target cells have receptors that latch onto only specific hormones, and each hormone has its own receptor, so that each hormone will communicate only with specific target cells that have receptors for that hormone. When the hormone reaches its target cell, it locks onto the cell’s specific receptors and these hormone-receptor combinations transmit instructions to the inner workings of the cell. When hormone levels reach a certain amount, the endocrine system helps the body keep that level of hormone in the blood. For example, if the thyroid gland has secreted the right amount of hormones into the blood, the pituitary gland senses the normal levels in the bloodstream and adjusts its release of thyrotropin, the hormone that stimulates the thyroid to produce hormones.

March 20, 2025 | Endocrine system diseases and disorders happen when one or more of the glands in the system are not working well. Hormones may be released in amounts that are too great or too small for the body to work normally. These irregularities are also called a hormone imbalance. There may not be enough receptors, or binding sites, for the hormones so that they can direct the work that needs to be done. These hormone imbalances may be the result of a problem with the system regulating the hormones in the blood stream, or the body may have difficulty controlling hormone levels because of problems clearing hormones from the blood. If you or your physician suspects that you have an endocrine disorder, you may need a specialist called an endocrinologist, a doctor who diagnoses and treats endocrine system diseases. They know how to treat endocrine conditions, which are often complex and involve many systems and structures within your body.