PATHOLOGY

Detailed explanation-1: -The first defined hormone and its discovery In 1902, William Bayliss and Ernest Starling found that in response to the delivery of acidic fluid from the stomach to the intestine, secretin, an internal secretion, was released into the blood from the endocrine cells of the duodenum.

Detailed explanation-2: -Hormones are molecules that are produced by endocrine glands, including the hypothalamus, pituitary gland, adrenal glands, gonads, (i.e., testes and ovaries), thyroid gland, parathyroid glands, and pancreas (see figure 1).

Detailed explanation-3: -A hormone (from the Greek participle , “setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior.