General features Relationships between endocrine and neural regulation The meaning of the term hormone has been extended beyond the original definition of a blood-borne secretion, however, to include similar regulatory substances that are distributed by diffusion across cell membranes instead of by a blood system. This mode of discharge (directly into the bloodstream) is called endocrine secretion. The classical view of hormones is that they are transmitted to their targets in the bloodstream after discharge from the glands that secrete them. Hormones carry out their functions by evoking responses from specific organs or tissues that are adapted to react to minute quantities of them. Hormone, organic substance secreted by plants and animals that functions in the regulation of physiological activities and in maintaining homeostasis. SpaceNext50 Britannica presents SpaceNext50, From the race to the Moon to space stewardship, we explore a wide range of subjects that feed our curiosity about space!.Learn about the major environmental problems facing our planet and what can be done about them! Saving Earth Britannica Presents Earth’s To-Do List for the 21st Century.Britannica Beyond We’ve created a new place where questions are at the center of learning.100 Women Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.COVID-19 Portal While this global health crisis continues to evolve, it can be useful to look to past pandemics to better understand how to respond today.Student Portal Britannica is the ultimate student resource for key school subjects like history, government, literature, and more.

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Hormones of adrenal gland