• A system of glands and cells that make hormones that are released directly into the blood and travel to tissues and organs all over the body. The endocrine system controls growth, sexual development, sleep, hunger, and the way the body uses food.
  NCI Dictionary of Cancer Terms
  U.S. National Cancer Institute, 2021
• The body system that comprises the organs and glands that produce hormones that are secreted into the blood and control physiological functions that include reproduction, growth and development, metabolism, and stress responses.
  NCI
  U.S. National Cancer Institute, 2021
• The system of glands that release their secretions (hormones) directly into the circulatory system. In addition to the ENDOCRINE GLANDS, included are the CHROMAFFIN SYSTEM and the NEUROSECRETORY SYSTEMS.
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2025
• (endocrine gland/system) Ductless glands that secrete substances which are released directly into the circulation and which influence metabolism and other body functions.
  CRISP Thesaurus
  National Institutes of Health, 2006
• The endocrine system coordinates functioning between different organs through hormones, which are chemicals released into the bloodstream from specific types of cells within endocrine (ductless) glands. Once in circulation, hormones affect function of the target tissues, which may be another endocrine gland or an end organ. Some hormones...
  Merck Manuals
  Merck & Co., Inc., 2025
• The endocrine system coordinates functioning between different organs through hormones, which are chemicals released into the bloodstream from specific types of cells within endocrine (ductless) glands. Once in circulation, hormones affect function of the target tissues, which may be another endocrine gland or an end organ. Some hormones...
  Merck Manuals
  Merck & Co., Inc., 2025
• The endocrine system�the other communication system in the body�is made up of endocrine glands that produce hormones, chemical substances released into the bloodstream to guide processes such as metabolism, growth, and sexual development. Hormones are also involved in regulating emotional life.
  Medscape
  WebMD, 2025
• Human endocrine system, group of ductless glands that regulate body processes by secreting chemical substances called hormones. Hormones act on nearby tissues or are carried in the bloodstream to act on specific target organs and distant tissues. Diseases of the endocrine system can result from the...
  Encyclopedia Britannica
  Encyclopedia Britannica, Inc., 2025
• Endocrine system, any of the systems found in animals for the production of hormones, substances that regulate the functioning of the organism. Such a system may range, at its simplest, from the neurosecretory, involving one or more centres in the nervous system, to the complex array of glands...
  Encyclopedia Britannica
  Encyclopedia Britannica, Inc., 2025