Compare And Contrast Fast Twitch Fibres

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

Abstract: In this experiment the measurements of skeletal muscle fibers of the rabbit are in millimeters. The average length for the three muscle fibers after adding the solution A which contained only 0.25% ATP in distilled water was 20 mm. The average length for the three muscle fibers after adding the solution C which contained 0.5M KCl and 0.001M MgCl2 in distilled water was 1.77 mm and the average length for the three muscle fibers after adding the solution B which contained 0.25 % ATP and 0.5 M KCl with 0.001 M Mgcl2 in water was 1.77 mm.

In turn, this result in the allowance of the muscles to contract is involuntary and requires no thought.

These are the smallest of the muscle fibres. These will be red in colour as they have a good blood supply and will also have a dense network of blood vessels. They also contain many mitochondria to make them more efficient at producing energy using oxygen. They contract slowly and also fatigue slowly suiting them best to aerobic endurance activities such as the 10,000m. These fibres are most effective during the middle part of the race when the athlete has found a constant speed, allowing the muscles to work for longer, as they are not being over-exerted. This is because they give there energy over a long period of time allowing the athlete to run for a sustained period of time. They are also slow to fatigue because they have an incredibly high aerobic capacity, meaning the athlete will be able to run long distances without feeling tired. To be able run a long distances, the

Smooth muscle is one of three muscle fiber types found in animals. Unlike skeletal and cardiac muscle cells, smooth muscle cells are not striated, and have single nuclei. Smooth muscles are typically under control of the autonomic nervous system, and do not contract voluntarily. Smooth muscle contracts slowly,

These fibers are known as "white fibers" because they do not contain much blood. The major difference between a and b is type IIa uses oxidative glycolytic which uses oxygen to help convert glycogen to ATP. Type IIb fast glycolytic, which rely on ATP stored in the muscle cell to generate energy. These fast-twitch muscle fibers have a much high activation threshold than slow-twitch. These muscles are activated when slow-twitch are unable to sustain the force needed for the body. The major down fall of type IIa and type IIb is the ability to fatigue quickly. The fast-twitch muscle group is responsible for the growth and shape of particular muscles within the body. Fast-twitch fibers are better suited for weight lifting and sports such as football. Most bodily muscles are evenly made of slow-twitch and fast-twitch

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.

The three categories include, A-delta (Aδ) fibers, C fibers, and A-beta (Aβ) fibers. The A-delta fibers are medium lightly myelinated fibers that are stimulated by mechanonociceptors a severe mechanical deformation, or mechanothermal nociceptors which is extremes of temperature. The A-delta fibers causes reflex withdrawals before pain stimulus is induced in the body. The C fibers are small unmyelinated and are stimulated by mechanical, thermal, and chemical nociceptors. They convey the dull, aching, or burning feeling that are poorly localized and the feeling stay longer. The A-beta fiber are large myelinated fibers that transmit touch and vibration feelings but not the pain feeling. However, they play part in pain modulation (McCance & Huether, 2014).

Exercise 2: Skeletal Muscle Physiology: Activity 3: The Effect of Stimulus Frequency on Skeletal Muscle Contraction Lab Report Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1. During a single twitch of a skeletal muscle You correctly answered: b. maximal force is never achieved. 2. When a skeletal muscle is repetitively stimulated, twitches can overlap each other and result in a stronger muscle contraction than a stand-alone twitch. This phenomenon is known as You correctly answered: c. wave summation. 3. Wave summation is achieved by You correctly answered: a. increasing the stimulus frequency (the rate of stimulus delivery to the muscle). 4. Wave summation increases the force produced in the muscle.

The initial burst of speed and subsequent 5 seconds in the 100m sprint, is fuelled by the Phosphagen ATP- PC system as there is 4-5 times more Phosphocreatine (PCr) readily available in the skeletal muscles compared to that of ATP (1). The initial ATP stored is used within 2 seconds of maximal activity by the Myosin ATPase enzyme to cleave energy, leaving Adenosine Diphosphate (ADP)

By looking at the results for the twitch experiment, the results supported my hypothesis. In my hypothesis, I thought that the force generated by the muscle would increase if the stimuli were increasing. The significance to this is because it means that the skeletal muscle can create some type of contraction if the strength of the stimulus is strong enough. This means that the muscle won’t use an overflow of energy to create a high amount of tension if given a small stimulus (Holbrook and Leicht 2017). These skeletal muscles are able to use certain amounts of muscle fibers/motor unit with the strength of the stimuli.

Muscular endurance is very important for people playing sports and who have to sustain an activity for long periods of time. Muscular endurance is determined by how well your slow twitch muscle fibers are developed. In case your wondering what slow twitch muscle fibers are, I will explain. There are generally two types of muscle fibers in your body, slow twitch and fast twitch. Slow twitch muscle fibers cannot exert as much force as fast twitch, but can sustain an effort over a much greater period of time. Fast twitch muscle fibers can exert a great amount of force but for a very limited amount of time. Therefore, slow twitch equals endurance, while fast twitch equals strength.

Kathryn North, a neurologist and geneticist, sequenced the ACTN3 gene. North found that one variation she named the “X variant” of ACTN3, instructed muscles to produce less alpha-actinin-3, a protein North suspects is directly related to muscle performance. Furthermore North observed an “R variant” of ACTN3, which tells special “fast-twitch muscle fibers” to produce AA3 along side other muscles. Following this logic North deduces that runners with one or more copies of the X variant should preform substantially worse than runners with one or more copies of the R

twitch muscles. Fast twitch muscles have a fast form of myosin ATP and are very

The more stimuli per second, the greater the force generated by the muscle due to a