HORMONE

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Hormones are stable chemicals that are released into the ............................. from glands or other organs. Unlike ............................., which are also chemical messengers, hormones are ............................. lasting to remain active while they travel throughout the body. Steroid hormone is able to pass into the nucleus without the aid of a receptor bound to the nuclear envelope. Peptide hormones are polar molecules that are not able to cross the .............................. In order to carry out their response in the cell, they need to either be transported across the membrane or somehow trigger their response from outside the cell. They perform their function by binding to a receptor on the outside of the membrane, which activates a .............................inside the cell that carries out the response. Antidiuretic hormone (ADH), also called ............................., is released from the ............................. pituitary and stimulates .............................by the kidneys. Dehydration triggers the release of ADH from the posterior pituitary and the kidneys, in response, retain water from the blood that filters through the kidneys. Without ADH, or when it is suppressed by alcohol, the kidneys do not retain water from the blood and most of the water leaves the body in the ............................. ............................. stimulating hormone is released by the anterior pituitary gland and functions in stimulating color changes in reptiles and amphibians, but its function is unknown in mammals. The .............................pituitary releases adrenocorticotropic hormone (ACTH) in response to the secretion of corticotropin-releasing hormone (CRH) from the .............................. ACTH released from the anterior pituitary stimulates the ............................. cortex to secrete corticosteroid hormones. .............................released from the parathyroid glands is one of only two hormones that are absolutely essential for survival. PTH controls the levels of ............................. in the blood by stimulating the release of calcium from ............................. and by increasing calcium absorption and reabsorption. Too much calcium levels however in the blood can cause problems, so PTH must be released in the proper amounts. Cortisol is released from the ............................., it functions to maintain ............................. homeostasis in the body Individuals with type I diabetes do not produce enough ............................. and therefore require injections of insulin. The cells in the pancreas that produce insulin, called ............................. of the islets of Langerhans, are not functional in patients with type I diabetes. The ............................. gland is found deep in the brain of vertebrates and secretes the hormone melatonin. Melatonin functions in blanching the skin in lower vertebrates by reducing the dispersal of melanin granules. Melatonin may also be involved in the establishment of ............................. rhythms.