Effects Training Has on Muscle Cell Hypertrophy

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.

-Sarcoplasmic Reticulum (SR) then releases Calcium which binds to troponin in the thin filament, exposing myosin-binding sites;

Smooth muscle contraction occurs when calcium is present in the smooth muscle cell and binds onto calmodulin to activate myosin light chain kinase (Wilson et al., 2002). Phosphorylation of myosin light chains result in myosin ATPase activity thus cross-bridge cycling occurs causing the muscle to contract (Horowitz et al., 1996). There are two known models of excitation and contraction in smooth muscle, electromechanical coupling (EMC) and pharmomechanical coupling

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

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.

Rationale, Significance and Hypothesis. An extrinsic factor, which exerts a dominant influence on skeletal muscle fiber phenotype, is the nervous system. Buller et al. (1960) elegantly demonstrated the plastic nature of skeletal muscle fibers in response to changes in innervation type. Later, Lφmo and Westgaard (Lφmo and Westgaard, 1974; Westgaard and Lφmo, 1988) demonstrated that depolarization of muscle with specific patterns and frequencies of electrical activity are sufficient to cause changes in mature muscle fiber phenotypes. However, how myofibrillar gene expression and structural organization is affected by the frequency of impulses during activity, the amount of activity over time, or other characteristics of patterned activity is essentially unknown. To answer these questions will require the isolation and study of subsets of muscle-specific proteins in relation to different electrical activation patterns in vivo, an issue that cannot be easily addressed in preparations currently used in the study of muscle development and maintenance. However, using novel in vivo approaches can, in part, circumvent this difficulty.

Martini, F. H., Nath, J. L., and Bartholomew, E. F. “Muscle Tissue.” Anatomy & Physiology. 9th

The body has many amazing systems within it. The muscular system is on of the systems that is the most intriguing. Type I, Type IIa, and Type IIb comprise the muscular fiber types within the human body. Type I or Slow-twitch fibers contain mitochondria. These mitochondria use the oxygen that is taken in to create adenosine triphosphate (ATP). ATP fuels muscle contraction. Type I fiber is considered to be aerobic due to the use of oxygen. The slow-twitch muscle fibers are also known as red fibers. This alias is due to the dark red appearance cause by the amount of myoglobin within the fiber. Slow-twitch fibers are the first within the body to be activated due to having a lower activation threshold. They create their own energy source which allows these fibers to sustain force for a longer period of time. The negative aspect is they are unable to create a large amount of force. If the fibers are unable to generate the amount of force that is needed then the fast-twitch fibers will be activated.

When a muscle contracts, myosin heads in thick filaments bind to actin in thin filaments and pulls the thin filament, shortening the length of the muscle fiber. However, without Ca++ when troponin binds to actin, the tropomyosin moves into a position that

A strong belief in most gyms is that you have to lift heavy weights to build muscle. However, according to a study by Nicholas Burd, “lifting heavy weights may not be the most effective way to build muscle. Muscle growth, sometimes known as hypertrophy, is the development of mass, density, shape, and function of muscle cells. This adaptation allows the muscle to meet exercise, function induced stress. Muscle cells are sort of like a bunch of sticks bundled up for firewood. Myofibrils are cylindrical bundles of filaments composed of sarcomeres. Sarcomeres are the fundamental unit of muscle contraction and are composed of myosin and actin. After you work out, your body repairs or replaces damaged muscle fibers through a cellular process where it fuses muscle fibers together to form new muscle protein strands or myofibrils. These repaired myofibrils increase in thickness and number to create muscle hypertrophy (Kwon and Kravitz). Muscle growth occurs whenever the rate of muscle protein synthesis is greater than the rate of muscle protein breakdown. This adaption, however, does not happen while you actually lift the weights. Instead, it occurs while you rest. So how do you actually add muscle to your muscle cells? This is where satellite cells come in

650 muscles operate the body. The voluntary Skeletal Muscles are long, slender, multinucleate disks with obvious striations have T-tubules utilizing actin and troponin. All muscles need Ca2+. These aerobic and non-aerobic muscles obtain Ca2+ from the sarcoplasmic reticulum (SR). The, intrinsic system, ANS, hormone regulated, voluntary, aerobic muscle of the heart get their Ca2+ from SR and Extra Cellular Fluid(ECF). They utilize the same site of calcium regulation as smooth muscle and contain intercalated disks. Smooth muscle, also voluntary, SR and ECF, aerobic, utilizes calmodulin in the cytosol for its source of Ca2+.

supply more oxygenated blood in time to assist with the activity the muscle is undertaking. If a

form of myosin ATP and are not very good at delivering calcium to the muscle

Hypertrophy training is a very specific type of training. It is not a goal that all athletes may want to strive for. Hypertrophy training is training to increase overall muscle mass and muscle size in the individual. Some athletes may wish to increase their physical size, but not necessarily to the size of Arnold Schwarzenegger.

Another effect of exercise to muscular system is the enlargement of the muscle. As regular as you do an exercise in the gym by lifting weights, your body will continue adding size to meet the imposed demand (Jordan T.S.).Having a long term exercise can generate muscle fibers growth known as hypertrophy. Having a resistance training will increase overall synthesis which is the main building block for muscle. When you lift an overload weights it will increase the number of contractile filaments with in the muscle cells. This will make the enlargement of muscle cells that makes the entire muscle larger(Weir J., 2010).