Hormone Hormone A hormone (from the Greek participle “”, "to set in motion, urge on") is any member of a class of signaling molecules produced by glands in multicellular organisms that are transported by the circulatory system to target distant organs to regulate physiology and behavior. Hormones have diverse chemical structures, mainly of 3 classes: eicosanoids, steroids, and amino acid/protein derivatives (amines, peptides, and proteins). The glands that secrete hormones comprise the endocrine signaling system. The term hormone is sometimes extended to include chemicals produced by cells that affect the same cell (autocrine or intracrine signalling) or nearby cells (paracrine signalling).
Gastric glands neck cells" that produce mucus. This is thought to be different from the mucus produced by the gastric mucosa. Fundic glands found in the fundus and also in the body have another two cell types–gastric chief cells and parietal cells (oxyntic)). The chief cells are found in the basal regions of the gland and release a zymogen – pepsinogen, a precursor to pepsin. The parietal cells ("parietal" means "relating to a wall") are found in the walls of the tubes. The parietal cells secrete hydrochloric acid–the main component of gastric acid. This needs to be readily available for the stomach