PATHOLOGY

Detailed explanation-1: -Endocrine signaling: a cell targets a distant cell through the bloodstream. A signaling molecule is released by one cell, then travels through the bloodstream to bind to receptors on a distant target cell elsewhere in the body.

Detailed explanation-2: -A second type of specialized signaling cell that controls the behavior of the organism as a whole is an endocrine cell. These cells secrete their signal molecules, called hormones, into the bloodstream, which carries the signal to target cells distributed widely throughout the body (Figure 15-4D).

Detailed explanation-3: -Signals from distant cells are called endocrine signals, and they originate from endocrine cells. (In the body, many endocrine cells are located in endocrine glands, such as the thyroid gland, the hypothalamus, and the pituitary gland.)

Detailed explanation-4: -Endocrine glands make chemicals called hormones and pass them straight into the bloodstream. Hormones can be thought of as chemical messages. From the blood stream, the hormones communicate with the body by heading towards their target cell to bring about a particular change or effect to that cell.

Detailed explanation-5: -Endocrine signals travel through the bloodstream to reach target tissues and cells. Signals that originate in one part of the body and travel to their target through the bloodstream are called hormones. Growth hormone (GH) is a great example.