What are the anatomical, physiological, and cellular mechanisms?

*Technical Question* What are the mechanisms for growth, especially during the teen years?

• I am looking for an answer or answers that would relate to human biology, specifically at the cellular level. What hormones are related to bone activities? How are these hormones regulated by the body, age and other environmental factors? Further more, are such mechanisms consistent throughout the "growth" period, commonly known as until age 21? What website or other resources can I research into for this topic?

• Answer:

  "Growth is triggered in both boys and girls by increased levels of the sex hormone testosterone. This chemical also triggers the sexual organs to develop. In fact, the relationship between growth of the skeleton and puberty is so strong that a teenager's developmental age can be measured by looking at the maturity of the bones in their hand and wrist." "Control of Growth Hormones are chemicals produced by special cells in glands and other organs of the body; most hormones are produced by cells in the endocrine glands. These hormones, which are produced in very small amounts, are released into the bloodstream and travel to the "target organ" or tissue where they exert their effect. Several hormones are involved in regulating growth. Some act directly on target organs, while others act by triggering the production of other hormones, which activate specific organ functions necessary for growth. This finely tuned system can malfunction in several ways, causing abnormal growth. The pituitary gland is often called the master gland because it produces several hormones that control the functions of other glands. It is located in the middle of the skull below the part of the brain called the hypothalamus. The pituitary gland has two distinct parts: An anterior (front) lobe and a posterior (rear) lobe. The pituitary gland secretes its hormones in response to chemical messages from the hypothalamus, the part of the brain to which it is connected. Growth hormone is an anterior pituitary hormone whose main effect is to promote growth of body tissues. Other anterior pituitary hormones affect growth indirectly by working through other glands. These other hormones include: Thyroid Stimulating Hormone (TSH) - causes the thyroid gland to produce thyroid hormone, which regulates body metabolism and is essential for normal growth. Adrenocorticotropic Hormone (ACTH) - causes the adrenal glands to produce cortisol (stress hormone) and other hormones that enable the body to respond to stress. Too much cortisol will cause growth failure in a child. Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH) - cause the sex glands (ovaries or testes) to produce sex hormones, which are necessary for adolescent sexual development and the growth spurt that accompanies puberty. The major hormone produced by the posterior pituitary gland -is called vasopressin, or anti-diuretic hormone (ADH). It controls water output through the kidneys." hope this helps a little