Athletes use performance enhancing drugs to overcome physiological challenges that are not normally overcome. In the case of overcoming fatigue, athletes often use stimulants. “Use is made of these stimulants above all to push back the limits of fatigue in the central nervous system and in this way allow the organism to use its autonomous natural reserves” (Howald, 1978). As in any case, if all natural resources are fully used up then the community or organism will perish. Therefore, by using these stimulants athletes are over exerting themselves, and will eventually experience severe exhaustion. Death can even result if the athlete pushes too far enough beyond their natural limits.
Proper nutrition is key to avoiding fatigue. Obtaining
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Each muscle is made up of several individual muscle fibers bound together by connective tissue. Each muscle fiber contracts individually when stimulated, and each fiber fully contracts or it doesn’t contract at all. The smallest unit of a muscle fiber is a sacromere. Sacromeres are made up of actin and myosin filaments. Each sarcomere contracts and requires energy to do so. Like all other bodily functions, muscle contraction requires energy. Contraction requires an energy source of ATP. ATP stands for adenosine triphosphate and is made of one adenine molecule, one ribose molecule, and three phosphate molecules. ATP provides energy in many metabolic processes. It is synthesized in the process called glycolysis. Most ATP is produced in the electron transport chain (ETC), which takes place in the mitochondria. After ATP is synthesized it is sent to be used or stored for later use. The basic unit of muscle contraction is the sacromere. The sacromeres are attached at Z lines, made from actin filament. These Z lines give skeletal muscle its striated appearance. In each sacromere, there is an A band, this is where actin and myosin overlap. This overlap is the point of connection when shortening takes place. This shortening is a part of a theory called the Sliding Filament Theory. The Sliding Filament Theory explains how when a muscle is stimulated the
Introduction: According to the “Human Physiology Laboratory Manual “,BIOL 282 ,page 31 , the reason of performing this experiment is to learn how the muscle contraction occurs based on the molecular level and what kind of factors are involved .As a matter of fact, skeletal muscles contain a lot of nuclei because of the cell fusion while being developed and are made of cylindrical cells that have myofibrils. The myofibrils contain sarcomeres and the
In turn, this result in the allowance of the muscles to contract is involuntary and requires no thought.
These muscle tissue cells specialised to contract and move parts of the body. It is also capable of responding to stimuli. There are three types of muscle in the body such as: skeletal, cardiac and smooth. Each muscle is created of muscle fibers that are capable of contracting and returning back to original state-relaxation. Contraction causes movement of the skeleton, soft tissue, blood or specific material. Skeletal muscle is attached to the bones of the skeleton. Some facial muscles are attached to the skin. They have direct control over them through nervous impulses from our brain sending messages to the muscle. Contractions can vary to produce fast, powerful movements. These muscles also have the ability to stretch and contract to return to original shape. Cardiac muscles are found in the chambers of the heart such as the atria and ventricles. It is under the control of the automatic nervous system; however, even without nervous input contractions can occur. It is completely different to all the other muscles. Smooth muscles are also known as involuntary due to our inability to control its movement. This muscle is usually found in the walls of hollow organs
Muscle fibres, as shown in Diagram 1, consist of myofibrils, which contain the proteins, actin and myosin, in specific arrangements . The diagram illustrates how a muscle is made up of many fascicles, which in turn are made up of many endomysiums, and within them, many muscle fibres. Each muscle fibre is made up of many myofibrils that consist of sarcomeres bound end on end . Actin is a thin filament, about 7nm in diameter, and myosin is a thick filament, about 15nm in diameter , both of which reside in the sarcomere. They are held together by transverse bands known as Z lines . Diagram 2 shows actin and myosin filaments within a sarcomere, and the Z lines that connect them.
Myofibrils are made up of long proteins that include myosin, titin, and actin while other proteins bind them together. These proteins are arranged into thin and thick filaments that are repetitive along the myofibril in sectors known as sarcomeres. The sliding of actin and myosin filaments along each other is when the muscle is contracting. Dark A-bands and light I-bands reappear along myofibrils. The alignment of myofibrils causes an appearance of the cell to look banded or striated. A myofibril is made up of lots of sarcomeres. As the sarcomeres contract individually the muscle cells and myofibrils shorten in length. The longitudinal section of skeletal muscle exhibits a unique pattern of alternating light and dark bands. The dark staining, A-bands possess a pale region in the middle called the H-zone. In the middle of the H-zone the M-line is found, that displays filamentous structures that can join the thick filaments. The light-staining bands also known as I-bands are divided by thin Z-line. These striated patterns appear because of the presence of myofibrils in the sarcoplasm (IUPUI, 2016).
Martini, F. H., Nath, J. L., and Bartholomew, E. F. “Muscle Tissue.” Anatomy & Physiology. 9th
ATP is often referred to as the energy currency of life. The cells use a form of energy called ATP to power almost all activities, such as muscle contraction, protein construction, transportation of substrates, communication with other cells and activating heat control mechanisms. Adenosine Triphosphate (ATP), an energy-bearing molecule found in all living cells. Formation of nucleic acids, transmission of nerve impulses, muscle contraction, and many other energy-consuming reactions of metabolism are made possible by the energy in ATP molecules. The energy in ATP is obtained from the breakdown of foods.
Muscles contract through an action potential moving along a motor neuron toward the skeletal muscle and they connect to a neuromuscular junction acetylcholine vesicles being released binding on the sarcolemma causes Na+ influx in the muscle fiber generating an action potential within the muscle fiber action potential moves through the T-tubules Calcium channels open calcium is released into the cytoplasm actin-myosin binding sites and cross-bridges are activated by calcium ions between the actin/ myosin heads ATP is hydrolyzed to flex myosin head this flexion makes the actin filaments move close to the middle of the sarcomere The length of the sarcomere becomes shorter contraction. I would like to define a few terms discussed within this
This activity is the critical driving force of muscle contraction. The stream of action potentials along the muscle fiber surface is terminated as Acetylcholine at the neuromuscular junction is broken down by acetyl cholinesterase. The release of Calcium ions is ceased. The action of the myosin molecule heads is obstructed because of the change in the configuration of troponin and tropomyosin due to the absence of calcium ions. This will eventually cause the contraction to be ceased. Together with these physical processes, an external stretching force such as gravity pulls the muscle back to its normal length.
The desire to compete — and win — is as old as history itself. From the beginnings of sport, athletes have sought out foods and potions to turn their bodies into winning machines. As early as 776 BCE, the very first Olympic games, there are records of attempts to increase testosterone levels (“Steroid Abuse in Sports”). Ancient Greek wrestlers ate vast amounts of meat to gain muscle mass, and Norse “Berserker” warriors took hallucinogenic mushrooms before battle. The first competitive athletes to be charged for doping, however, were swimmers in 1860s Amsterdam. Doping of all kinds, from caffeine to cocaine to anabolics quickly spread to other sports (“Anabolic Steroids, a Brief History”).
The phosphate from an ATP molecule will bond to a protein called myosin. This will attract to an actin, which therefore causes muscles to contract. So, muscles are able to contract using the energy provided by the phosphate given off by ATP. ATP is also used in the formation of polymers. To build a polymer, the most efficient way to do this is by using a phosphate.
PEDs and steroids provide better stamina, stronger muscles, and more muscular endurance. "Society cares because steroid use is a form of cheating. Since steroids work so well, they create an unfair advantage for those who take them, and this breaks the social contract athletes have implicitly agreed to: We are going to have a fair contest. There are things we can and cannot do. Even if there were a safe performance-enhancing substance, if it weren't available to everybody, using it would still be cheating" (Dillingham). The end game will be actions that are increasingly violent, extreme, and meaningless, practiced by a class of chemical and or genetic mutant gladiators. The use of performance-enhancing drugs is not accidental; it is planned and deliberate with the sole objective of getting an unfair
how the sections move during a contraction. The Z line is in the middle of the I bands
Both of these muscles expand and contract as they have complex structures so it is essential how they do this. The cardiac muscle needs the contractions to occur in order to pump blood out of the atria and into the ventricles and round the circulatory system so the structure of this muscle shows the systole of the heart. The contractions of the skeletal muscle also depend on its structure. The binding and releasing of two strands of sarcomere is how the repeated pattern of contractions occurs. ATP is used to prepare myosin for binding to allow the contractions to happen. The skeletal and cardiac muscle also both has elasticity. The elasticity is used to restore the muscles back to their original lengths which enable them to resume back to their original length once they have contracted and been stretched.
In sports, the competitive drive to win can be very intensive between athletes. Winning in the game usually brings rewards to athletes both financially and psychologically. Such temptations and the consecutive pressures faced by athletes to excel in the sporting events, attempts to achieve a rival edge especially when the application of performance enhancing drugs by athletes in sports activities has becoming a new trend and relatively common. Performance enhancing drugs are used so athletes could achieve better results with least efforts, even as their health and their athletic careers will be placed in danger. That explains why athletes, sports people and body builders turn to performanc enhancing drugs.