Biology Study Sheet #4

Biology Study Sheet #4 - Muscles & Steroids Steroids...

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Steroids treat conditions that occur when the body produces abnormally low amounts of testosterone. However, the doses prescribed to treat these conditions are 10 to 100 times lower than the doses for performance. Muscles accomplish movement by PULLING on bones (not pushing). Most muscles are in antagonistic pairs. When the muscles contract, they pull on the bones and cause movement. It is by using antagonistic pairs of muscles that controlled movement is accomplished. The muscles of the body respond to stimuli provided by the nervous system. A motor neuron from the spinal cord carries a nerve impulse to the muscle cell. A neuron is composed of three parts (dendrites, cell body, axon) and that the impulse is carried to the muscle via an axon. The skeletal muscle fibers consist of columns of sarcomeres (muscle cells) The neurotransmitter that carries an impulse from a motor neuron to a muscle cell is called acetylcholine (ACh). When ACh binds to the muscle cell it causes sodium channels to open, which allows the depolarization wave to begin. To ensure that the muscle stimulus is for only a short time, there are enzymes which break down the neurotransmitter as quickly as it is released. The most common cause of paralysis is damage to the nerve fibers that are responsible for stimulating the muscle cells Nerve gas is absorbed through the lungs and causes disruption in the ability of the enzymes that break down acetylcholine from working properly Tetanus when the muscle contracts forcefully and cannot relax. Botulism bacteria produce botulism toxin, which can be injected into to muscles from causing wrinkling (Botox) There are many forms of arthritis, but the most common is osteoarthritis. It is estimated that is preventable in many cases. Estimated that by 2020 there will be over 40 million Americans suffering from this condition. Cartilage can be worn down due to overuse of the joint, or poor muscles and tendons that control the joint movement. Excess weight is often a contributing factor to this condition. As the cartilage breaks down, inflammation sets in resulting in the swelling. Genetic mutations have also been linked to causing this. According to Newsweek, about 300,000 students between the eighth and 12th grades used steroids. Not all of this is by male athletes. A third are by girls and some students take them because they want to look like models. Transgenic Organisms Researchers have launched more than 300 trials of genetically engineered crops to produce everything from fruit-based hepatitis vaccines to AIDS drugs grown in tobacco leaves. They call this biopharming.
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Environmentalists are worried that unnaturally combined genes will spread all over. Consumer advocates, who have never warmed to today's genetically modified foods, fear that plant-grown drugs and industrial chemicals will end up on dinner tables. The Gov’t is developing regulations aimed at assuring
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Biology Study Sheet #4 - Muscles & Steroids Steroids...

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