Hormones Topic B6

Production and function (B.6.1) primarily chemical messengers produced in endocrine glands secreted directly into bloodstream and transported to various organs, tissues, or cells in the body

have a variety of functions –adrenaline produced in the adrenal glands the ‘fight or flight’ hormone stimulant –dilates pupils and airways, increases heart beat and the release of sugar into the bloodstream –thyroxine produced in the thyroid gland regulates the body’s metabolism

–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 contain a steroid backbone consisting of three six-membered rings and a five- membered ring fused together

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

MaleFemale

cholesterol

Oral contraceptives (B.6.3) most commonly used is called the combined oral contraceptive pill –contains a combination of estrogen and progesterone –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) several steroids that resemble testosterone have been synthesized use –promote increased muscle mass and growth –can be given following injuries to rebuild muscle abuse –can enhance athletic performance

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