The Effect Of Different Stretching Techniques On Myosin Actin

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.

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

For muscle to contract, actin and myosin filaments need to slide past each other, causing the sarcomere to shorten in length . Each myosin filament has a protruding bulbous head, which can bind with the binding sites on the

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).

As the neurotransmitters bind to the receptor on the muscle cells, it allows calcium or Ca2+. As calcium ion(s) enters the muscle cell it activates troponin and tropomyosin which causes muscle cells to change conformation and uncover the A:M binding site. As long as the Calcium ion(s) levels remain high, actin and myosin cycle between bound and unbound states, such as contraction of the muscles. When Calcium ion(s) decreases, tropomyosin blocks myosin binding sites and skeletal muscle tissue entering the resting

(Table 1) ATP alone causes myosin to break the cross-bridge and allow the myosin to reattach to the actin causing a muscle contraction, since the solution we used had ATP; I believed that that was enough to cause the fiber contraction. I thought that we had done our experiment in correctly because there was no muscle contraction. I believed that it was due to the amount of solution we added to the fiber. We re did the experiment and added four drops of the solution but there was no muscle contraction as

Heart contraction is produced by stretching of sarcomere units, which produces strokes between myosin head and actin monomers located in the thin filament of sarcomere (Robinson, Dong et al. 2004). Changes in the resting tension of heart muscle affect the range of heart contraction. The heart has the capacity to adjust its contraction force as result of variations in ventricular filling (end-diastole), this effect is known as the Frank–Starling Law (Sequeira and van der Velden 2015). An increased systolic contraction is the results of the ventricle stretching due to greater end-diastolic volume happens (Schneider, Shimayoshi et al. 2006). However,

The sarcomere is the smallest unit of muscle fiber and linked end-to-end within a muscle fiber, which is located between two Z lines and is approximately 2.5 μm long (Toldrá, 2002). The overlapping arrangement of myofilaments results in dark (A) and light (I) bands will cause the striated appearance. The A band is known as area where the actin and myosin overlap. When the area in the A band contains no thin filaments, it will called as H zone, while I band is the region which contains no thick filaments (Feiner, 2006). I bands are bisected by Z-lines which results in dark lines, while A bands bisected by M-lines (Toldrá, 2002). Actin and myosin are connected to the Z line and M line,

As discussed in paper one, readers can see the complexity that lies behind muscle fibers and the contractile units that make up each muscle cell. At the normal physiology level, muscle fibers exist as complex bundles of small muscle filaments. These filaments, known as actin and myosin bind in such a way that allows for sarcomere contraction. In assistance with calcium flowing into muscle cells, proteins known as tropomyosin and troponin ultimately allow “cross bridging” to occur. Throughout the body three types of muscle fibers exist, these types of fibers are slow oxidative, fast oxidative and fast glycolytic. Activation or recruitment of these fibers varies from person to person depending on the muscle specificity needed to perform a given contraction. In other words the innervation of each fiber depends solely on the muscle needed to engage in a specific exercise. By first knowing the anatomy behind a muscle cell one can then have a better understanding of the effects training has on muscle cell hypertrophy.

Many research studies have been conducted till date to investigate the effects of static stretching on lower limb force production and agility in athletes. As contrary to the popular belief, most of the research data suggest that static stretching immediately prior to a competition enhances the rate of injuries instead of reducing them. An acute bout of stretching does not improve force production and agility in basketball players. When maximal velocity contraction, power, jump height, jump force, and jump velocity were measured after static stretching, it was observed that the session

Muscle myopathy is a disease in which the skeletal muscle in human body weakens and difficult to move (Carnell et al., 2012). This disease can also affect the smooth muscle in respiratory tract that leads to shortage in oxygen and carbon dioxide accumulation in blood. This disease is caused by the mutation of ATP-binding activity of actin filaments. Therefore, muscle contraction cannot occur, being that ATP is essential for the muscle to contract. There is no effective cure for this disease (NINDS, 2015). However, some treatments can be done to overcome the weakness of the muscle. Treatment for this disease is based on the muscle condition of the patient. Some physical therapy and using brace as a support of the muscle can help the patient who

The sarcomeres are grouped into two types of filaments, actin filaments and myosin filaments. Actin filaments are thin protein fibers that are pulled to cause muscle contraction. The ends of the actin filaments

The sliding filament theory of a muscle action has five phases. The first phase is resting. In this phase there is no calcium available to bind the myosin to the actin. This is the normal state of the muscle until activated by the excitatory phase. During this second phase, the sarcoplasmic reticulum becomes stimulated. This releases calcium ions and binds with troponin. This is a protein that is strung along the actin filaments. Tropomyosin runs along the actin filaments. The actin is pulled closer to the sarcomere. The contraction phase is when it gets interesting. ATP is broken down into ADP in order to create energy for the contraction. To return to the normal state of the muscle, ATP replaces ADP and aids in detachment of the myosin cross

Only one contraction was seen in the results. This could be because the muscle was put into the warm ringer and did not warm up with the ringer slowly. The results that should have been obtained was at 40°C the first shortening of myosin should have taken place. Myosin will start to move to a state of disorder at 20°C, and start to denature at 40°C causing the shortening (Leepo, 2003). Then at 47°C a shortening should have taken place for tropomyosin and at 56°C a shortening for troponin. Troponin and actin has an effect on the thermal properties of tropomyosin (Kremneva et al., 2003). Troponin I and Troponin T have not shown any thermal changes up to 100°C in a previous study, Troponin C was the only component that denatured at 56°C (Kremneva