The endocrine system and hormones

The endocrine system is a network of glands that make hormones, chemical messengers released into the blood that travel throughout the body but affect only target cells with matching receptors. Compared with the nervous system, which sends fast electrical signals along nerves, hormones usually act more slowly but have longer-lasting effects, such as regulating growth, metabolism, and development. Major glands include the pituitary gland at the base of the brain, often called the master gland because many of its hormones control other glands; the hypothalamus, a part of the brain that links the nervous and endocrine systems by directing the pituitary; the thyroid gland in the neck, whose hormones set the body's metabolic rate; the adrenal glands on top of the kidneys, which release adrenaline (epinephrine) in the fight-or-flight response to stress; and the pancreas, which releases insulin and glucagon to control blood sugar. Most hormone levels are kept in balance by negative feedback: once a hormone's effect is achieved, signals reduce the release of more of it. Too much or too little of a hormone can cause disorders, such as diabetes, when the body does not make enough insulin or does not respond to it properly.

This explanation is AI-generated and can occasionally be wrong. 🚩 Report