The endocrine system is referring to the collection of cells, glands, and tissues of an organism that secrete hormones directly into the bloodstream (some of which are transported along nerve tracts]citation needed[) to control the organisms' physiological and behavioral activities. The endocrine system is in contrast to the exocrine system, which secretes its chemicals using ducts. The word endocrine derives from the Greek words "endo" meaning inside, within, and "crinis" for secrete. The endocrine system is an information signal system like the nervous system, yet its effects and mechanism are classifiably different. The endocrine system's effects are slow to initiate, and prolonged in their response, lasting from a few hours up to weeks. The nervous system sends information very quickly, and responses are generally short lived. Hormones are substances (chemical mediators) released from endocrine tissue into the bloodstream where they travel to target tissue and generate a response. Hormones regulate various human functions, including metabolism, growth and development, tissue function, sleep, and mood. The field of study dealing with the endocrine system and its disorders is endocrinology, a branch of internal medicine.
Features of endocrine glands are, in general, their ductless nature, their vascularity, and usually the presence of intracellular vacuoles or granules storing their hormones. In contrast, exocrine glands, such as salivary glands, sweat glands, and glands within the gastrointestinal tract, tend to be much less vascular and have ducts or a hollow lumen.
a Mexican American b Mexican Canadian
c Mexicans in Spain
Mexican people (Spanish: Pueblo mexicano (collective), Mexicanos (individuals)) refers to all persons from Mexico, a multiethnic country in North America, and/or who identify with the Mexican cultural and/or national identity.