Hormones are chemical messengers produced by glands and organs in the body that travel through the bloodstream to target tissues or organs, where they regulate various physiological processes and behaviors. They coordinate functions such as growth, metabolism, reproduction, mood, and many other bodily activities by sending signals that tell cells what to do and when to do it
. Hormones are essential for maintaining homeostasis and normal development in animals and plants. They can be steroids, peptides, amino acid derivatives, or even gases, and they exert their effects far from their site of production
. The endocrine system, which includes glands like the pituitary, thyroid, adrenal glands, pancreas, ovaries, and testes, is responsible for producing and releasing hormones. Because hormones act in very small amounts, even minor changes in their levels can lead to significant effects on the body and may cause medical conditions if imbalanced
. Examples of hormone functions include regulating blood sugar (insulin), controlling growth (growth hormone), managing stress response (cortisol), and influencing sexual development (estrogen, testosterone)
