The integrin system is composed of ductulus glands that secrete hormones, chemical messengers that control homeostasis. The hypothalamus controls the secretions of the pituitary. Nerve cells in the hypothalamus send releasing hormones to anterior pituitary to release hormones. Hormones are growth hormone, TSH, ACTH, MSH, FSH, LH, and prolactin. Hormones produced by the hypothalamus are stored in the posterior lobe of the pituitary. Hormones are ADH, increases the reabsorption of water, and oxytocin contracts the pregnant uterus. Pituitary gland is called the master gland because it controls the function of other endocrine glands. T3 and T4 regulates metabolism of nutrients for normal growth and matures the nervous system, calcitonin lowers blood calcium and phosphates. Parathormone raises the blood calcium to normal levels. Madula secreeds adrenaline and norepinephrine that prepare the body for stressful situations. Cortex secreeds, al dastorone regulates sodium reabsorption and potassium excretion in the kidney. Cortisol reduces inflammation. Androgens stimulate male sex characteristics. Testes produce testosterone. Ovres produce estrogen and progesterone. Hormones necessary for development of reproductive systems and secondary sex characteristics. Diamacin is necessary for the development of T lymphocytes. Melatonin regulates the body, wake, and sleep cycles and inhibits the function of the reproductive system. Serotonin acts as a neurotransmitter and vasoconstrictor. Ilets of Langerhans produce insulin and glucagon that regulate the blood glucose level essential for energy.