Endocrinology is a branch of biology and medicine studies the hormones and the endocrine system. The endocrine system is a complex network of different glands and organs that secrete hormones into the bloodstream.
Hormones are molecules formed by peptides, amino acids, steroids that are produced by specialized cells in the endocrine glands and transported to target cells and organs throughout the body where they can bind to specific receptors on the surface or inside their target cells, causing a response that can affect various physiological processes.