Hormones Topic B6

Production and function (B.6.1) primarily chemical messengers produced in endocrine glands – –organs that secrete directly into bloodstream and transported to various target cells in the body hormone examples are…….

epinephrine (adrenaline) –produced in the adrenal glands –the ‘fight or flight’ hormone –stimulant dilates pupils and airways, increases blood supply to heart and muscles thyroxine –produced in the thyroid gland –regulates the body’s metabolism

ADH (antidiuretic hormone) –produced in the hypothalamus –most important function is to conserve water by reducing the amount of water passed out in the urine

aldersterone –produced in the adrenal glands – –serves as the principal regulator of the salt and water balance of the body estrogen – –produced in the ovaries – –primary female sex hormones – –promote the development of female secondary sexual characteristics – –involved in the thickening of the endometrium and other aspects of regulating the menstrual cycle

progesterone – –produced in the ovaries and the adrenal glands – –plays important roles in the menstrual cycle and in maintaining the early stages of pregnancy testosterone – –secreted primarily by the testes – –promoting secondary sexual characteristics such as increased muscle, bone mass, and the growth of body hair

insulin – –protein (51 amino acids) produced in the pancreas – –regulates blood sugar by triggering cells to uptake sugar stimulating the liver to store glucose in the form of glycogen – –diabetics produce too little insulin

Compare structures of cholesterol and sex hormones (B.6.2) all are steroids all have backbone consisting of three six- membered rings and one five-membered ring fused together

but they differ in the type and position of functional groups on the steroid backbone

cholesterol

MaleFemale

Oral contraceptives (B.6.3) most commonly used is called the combined oral contraceptive pill –contains a combination of estrogen and progesterone take these for 21 days then a placebo for 7 days so period still occurs but no release of eggs

–mimics pregnancy by keeping hormones at high levels prevents ovulation from occurring makes the lining of the uterus thinner so that it is unsuitable for implantation of a fertilized egg makes the mucus in the cervix thicker to prevent sperm from reaching the egg

Use and abuse of steroids (anabolic) (B.6.4) use –the “pill” as previously mentioned –hormone replacement therapy (HRT) for women going through menopause –promote increased muscle mass and growth after a serious illness or injury abuse –can enhance athletic performance in order to win competitions

– –taking large doses cause harmful side effects – –in men: impotence, baldness, problems in urinating, smaller testes – –in women: changes in secondary sex characteristics, build up of muscles and increased facial hair – –both men and women also experience violent temper/aggressive behavior liver tumors, high blood pressure and heart attacks