MICROANATOMY

Detailed explanation-1: -The chemical product of an endocrine gland is called a hormone. Hormones turn on, turn off, speed up, or slow down the activities of different organs and tissues. You can think of a hormone as a chemical messenger. Hormones are carried throughout the body by the blood.

Detailed explanation-2: -Hormone production and release are primarily controlled by negative feedback. In negative feedback systems, a stimulus elicits the release of a substance; once the substance reaches a certain level, it sends a signal that stops further release of the substance.

Detailed explanation-3: -It makes the thyroid hormones thyroxine (thy-RAHK-sin) and triiodothyronine (try-eye-oh-doe-THY-ruh-neen). These hormones control the rate at which cells burn fuels from food to make energy. The more thyroid hormone there is in the bloodstream, the faster chemical reactions happen in the body.

Detailed explanation-4: -Lipid-derived (soluble) hormones can enter the cell by diffusing across the plasma membrane and binding to DNA to regulate gene transcription and to change the cell’s activities by inducing production of proteins that affect, in general, the long-term structure and function of the cell.

Detailed explanation-5: -Humoral Stimuli A humoral stimulus refers to the control of hormone release in response to changes in extracellular fluids such as blood or the ion concentration in the blood. For example, a rise in blood glucose levels triggers the pancreatic release of insulin.