hormonal and metabolic disorders
Endocrine Function
Introduction
The main function of Endocrine Glands is to secrete hormones directly into the bloodstream. Hormones are chemical substances that affect the activity of another part of the body (target site). In essence, hormones serve as messengers, controlling and coordinating activities throughout the body. (See also Upon reaching a target site, a hormone binds to a receptor, much like a key fits into a lock. Once the hormone locks into its receptor, it transmits a message that causes the target site to take a specific action. Hormone receptors may be within the nucleus or on the surface of the cell. Ultimately, hormones control the function of entire organs, affecting such diverse processes as growth and development, reproduction, and nutrient metabolisms. Hormones also influence the way the body uses and stores energy and control the volume of fluid and the levels of salts and sugar (glucose) in the blood. Very small amounts of hormones can trigger very large responses in the body. Although hormones circulate throughout the body, each type of hormone influences only certain organs and tissues. Some hormones affect only one or two organs, whereas others have influence throughout the body. For example, thyroid-stimulating hormone, produced in the Overview of the Pituitary Gland , affects only the thyroid gland. In contrast, thyroid hormone, produced in the Most hormones are derived from Proteins or their building blocks (called amino acids). Others are steroids, which are fatty substances derived from cholesterol. 