Writing Assignment 1
1. Discuss the relationship between distribution of muscle fiber type and performance. How might exercise training modify or change a person’s fiber-type distribution? Muscle fiber types as we understand have two types which are type I and type II. Type I is which is also called the slow twitching muscles has the ability to generate high amount of force. Type II are fast twitching muscles which generate a lower amount of force. Type I fibers take approximately 110 ms to reach peak tension when stimulated. Type II fibers, on the other hand, can reach peak tension in about 50 ms. (Wilmore, J., 2008) According to the article in http://www.brianmac.co.uk/, called “Muscle Type”, Type I muscle fibers are mostly found in the
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The liver synthesizes glycogen from glucose which is process called glycogenesis. After that process, glycogen or glucose must be converted to glucose-6-phosphate before energy can be generated. Glucose-1-phosphate is converted to glucose-6-phosphate. Glycolysis requires 10 to 12 enzymatic reactions for the breakdown of glycogen to pyruvic acid, which is then converted to lactic acid. All steps in the pathway and all of the enzymes involved operate within the cell cytoplasm. (Wilmore, J.) For each glycogen broken down, the result is 3 molecules of ATP.
3. Describe how a nerve impulse is transmitted along its axon. Nerve impulses are a results of chemicals of neurotransmitters along the neurons dendrites and soma. Understanding that this occurs throughout our body since nerves are connected all over. The neurotransmitter begins the stimulation by opening the neuron. The action along an axon of a neuron is an interchange of Sodium and Potassium ions, which propagates the impulse the action potential. (http://hyperphysics.phy) The transfer of sodium and potassium ions between the nerve cells is a process during nerve impulse. The process begins
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.
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.
3. At the axon terminal, each action potential causes the release of neurotransmitter. This neurotransmitter diffuses to the receiving end of an interneuron, where it binds to receptors and causes
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 end of the axon spread into some shorter fibers that have swellings on the ends called synaptic knobs. The synaptic knob has a number of little saclike structures in it called synaptic vesicles. Inside the synaptic vesicles are chemicals hung in fluid, which are molecules of substances called neurotransmitters which are inside a neuron and are going to transmit a message. Neurotransmitter are released into the synapse from synaptic vesicles. The neurotransmitter molecules bind to receptor sites on the releasing neuron and the second neuron or glands or even muscles causing a reaction.
As the message arrives at the end of the nerves, the message is transmitted to the muscles. Before the message is transmitted to the muscles it has to pass the space between the end of the nerve and the muscle, and that space is called neuromuscular junction. The message is transmitted from the brain to the end of the nerve and from the nerve to the neuromuscular junction, and when the message arrives the chemical called neurotransmitters are released.
As well as these there are also the axon of the cell which is covered in myelin sheaths which carried information away from the cell body and hands the action potentials, these are small short bursts of change in the electrical charge of the axon membrane through openings of ion channels, off to the following neurons dendrites through terminal buttons at the end of the axons. Whenever an action potential is passed through these terminal buttons it releases a chemicals that pass on the action potential on to the next neuron through the terminal button and dendrite connection. The chemicals that are
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.
The tissue of skeletal muscle is made of muscle fibers and have a strip appearance. Muscle fibers are grouped together to create muscle groups and is often paired with other groups in two and sometimes even four. There are two types of skeletal muscle; fast-twitch and slow-twitch.
Once in the synapses, the impulses triggers the release of chemical messages called neurotransmitters; which then bind to receptors on the receiving cell as the transmission of the impulse repeated again. The message or impulse continues traveling from one neuron to the next throughout the body until it reaches its destination as it relays a signal. All of this activity happens in less than a split second and without conscious thought. At the end of this process, the brain has the task of interpreting the message and making the decision as to what to do with this new information. (Carlson, 2011.Pg.45-52)
In this study, skeletal muscle-specific force, maximal isometric force per cross-sectional area of the muscle, concentric force, contractile properties, activation capacity and the structural characteristics of the muscle were tested. The results showed through the measures of body composition and physical function. (Jordan, what were you trying to say here? I’m a tad confused.)
Muscle fiber CSA and the minimum Feret’s diameter were measured in a total of 1678 muscle fibers in the GG, and in a total of 1604 muscle fibers in the SG. As noted previously, the HG was not included in this analysis due to the extent of elongated or elliptical fibers present in the
There are three types of muscle tissues in the human body: skeletal, smooth and cardiac muscle. Skeletal muscles are striated muscles that attach to the bone by tendons and permit movement. Skeletal muscles promote movement by contracting and relaxing in response to voluntary messages from the nervous system, deeming skeletal muscles, the only voluntary muscles in the human body. Smooth muscles are involuntary muscles found inside the walls of the stomach,
Neurotransmitters are substances that are produced by neurons and are transferred chemically. Once an axon releases these substances the action potential moves through the axon into the terminal branch where they are kept and then released. This helps neurons pass impulses to other
The impulse is then sent to another neuron, and the process repeats until the nerves are at rest. The effect of the signals depends on what the target is. If the target of the signal is a muscle cell, the effect might be a muscle contraction. The speed of the electrical impulse depends on the size of the nerve fiber. In small nerves, the rate it transmits impulses is from a half to two meters a second. The larger the diameter of the nerve fiber, the higher rate of conducting impulses. There is less electrical resistance in thick fibers. When nerve impulse jumps from one node (gaps in nerve fibers) to the next, it is called saltatory conduction. Saltatory conduction conducts faster because it contains an insulator that prevents leakage of currents. The rate of conduction is 2 to 120 meters a second. Not all nerves conduct impulse electrochemically. Some impulses jump from nerve to nerve, bypassing the synapse. Unlike other cells, once neurons are lost, they can’t be regenerated. Fortunately, there are about 10 billion neurons and they have other cells to aid them in carrying messages to other nerves. But if nerves are severed, the nerve fibers can regenerate if the two ends are reattached precisely. However, restored functions may produce different actions because the nerves might not be connected to the right channel.