Muscle Contraction Lab Report

Improved Essays
The use of neurons and muscle is utmost for any animal’s survival. The experiment studies the principles of muscle contractions and nerve conductions, and the characteristics of muscle twitches and AP. The nerve and muscle work in conjunction and allow organisms to be motile. Thus looking at the properties and understanding the process has immense influence on science and the world in general. Through the experiment it was determined that an increase in stimulation amplitude in both muscle and neurons correlates positively with their activity. In increase in amplitudes in muscle causes recruitment of more motor unit thus allowing contraction of more muscle fibers. Similarly, increasing intensity in neurons helps increase the CAP by recruiting …show more content…
However, there are only a limited motor unit and nerve fibers in a given organism therefore, there will be point at which all the units and fibers will be saturated and the intensity of stimulation. A single AP can cause a twitch in a muscle. The latent time in this experiment was 33 ms. This signifies the time it takes for the stimulus to depolarize the t-tubule, send an AP towards the muscle fiber, activate the Ca++ channels, and to allow actin myosin to join and start a contraction. The rate of contraction compared to the rate of relaxation of the muscle was found to be higher. This is due to Ca++ channels opening and allowing diffusion of Ca++ across the SR membrane down its concentration gradient. However, relaxation requires the use of Calcium ATP transporter, which actively transports Calcium and uses ATP as energy against its concentration gradient. Furthermore, the movement of transporter is slower because it must interact with two molecules (Ca++ and ATP) to transport. When a muscle is overworked, it causes fatigue and results in a longer relaxation period. This can be explained by the use of ATP. After overworking, the ATP reservoir is depleted in a muscle cell due to the need to constantly efflux Ca++ ion …show more content…
This is due to the refractory period of the CAP. At a certain point following a depolarization, the cell hyperpolarizes and causes a destructive effect on the upcoming CAP thus lowering its amplitude. According to this experiment, the relative refractory period of the nerve used was 5 ms. After which the amplitude of the second CAP was not affected. Finally, the changes in temperature also have effect on the duration of CAP. Decreasing the temperature lowers the kinetic energy of the ions thus increasing the time it takes for them to efflux/ influx and slowing the propagation of the CAP. Furthermore, protein also get effected as they are only capable of working at their optimal temperature, changes in temperature may lead to a decrease in activity and slowing down the signal propagation even

Related Documents

  • Superior Essays

    Muscle Fatigue Lab Report

    • 1289 Words
    • 6 Pages

    Surface Electromyography Amplitude During Sustained Isometric Contractions Connor Howe 31451131 HMKN 310 UBC Okanagan Greg duManoir October 18, 2015 Introduction Muscle fatigue is the result of a series of structural, metabolic and energetic changes in muscle fibers caused by changes in nervous system efficiency as well as decreased oxygen and nutrient supply (Cifrek, Medved, Tonković, & Ostojić, 2009). A major driving force behind muscle fatigue is lactate buildup. As lactate builds up there is a shift in intracellular pH levels which causes a change in the waveform shape of the motor unit action potential. This causes a decrease in the conduction velocity of the muscle fiber.…

    • 1289 Words
    • 6 Pages
    Superior Essays
  • Improved Essays

    Jenbrassik Case Study

    • 841 Words
    • 4 Pages

    Also, both the alpha and gamma motor neurons meet at the same effector muscles. Furthermore, when the extrafusal fibers of the muscle spindle contract, the intrafusal fibers change length in correlation to the muscle tone to activate the feedback to the brain, which is done by the gamma neurons. The feedback process is performed by afferent neurons located in the spinocerebellar tract, in which they relay the message to the central nervous system regarding the length and tension of the muscle fibers.…

    • 841 Words
    • 4 Pages
    Improved Essays
  • Decent Essays

    Unit 3 Muscle Lab

    • 248 Words
    • 1 Pages

    The brain sends impulses to muscles, causing them to contract and pull on the bones that they’re connected to. In detail, muscle contraction starts when the central nervous system sends electrical impulses to the neuromuscular junction and causes it to release Acetylcholine. Acetylcholine then binds to the receptors present on the muscle…

    • 248 Words
    • 1 Pages
    Decent Essays
  • Superior Essays

    These action potentials are affected because the responses of inhibiting and excitatory potentials throw off the balance of the nerve firing. The animal of interest is…

    • 1100 Words
    • 4 Pages
    Superior Essays
  • Improved Essays

    The firing of gamma motor neurons in sync with alpha motor neurons pulls muscle spindles, innervating the muscle. The spindle is innervated by type Ia sensory fiber that goes on to synapse with alpha motor units. Therefore, there are more motor units being put to work and the type 1a afferents maintain their sensitivity.…

    • 399 Words
    • 2 Pages
    Improved Essays
  • Improved Essays

    The source of energy in muscles is called adenosine triphosphate. The fibers making up the muscles link with adenosine triphosphate to obtain the energy required to allow the muscles to contract and relax (Dickinson, 2000). The fibers after obtaining the energy and receiving the necessary signal, they perform the required action. In the limbs, the signals are to allow movement or stop movement depends on the concentration of the intercellular calcium ions. Around the limbs, the muscles contain a very elastic protein known as titin (Ting, 2012,).…

    • 974 Words
    • 4 Pages
    Improved Essays
  • Decent Essays

    Twitch is a single muscle fiber stimulated briefly that produces a quick contraction and relaxation, but not enough to do any full muscle movement. The first phase is called the lag phase as a stimulation occurs, a brief 2 millisecond lag between stimulus and contraction as the calcium is being released from the SR. The second contraction phase occurs the muscle cell shortens, and external tension is visible. The third and final phase is the relaxation phase causes the tension decreases and the calcium is drawn back into the SR.…

    • 421 Words
    • 2 Pages
    Decent Essays
  • Improved Essays

    Muscle Fatigue Lab Report

    • 497 Words
    • 2 Pages

    INTRODUCTION The proteins actin and myosin is the caused of excitement of skeletal muscle. It can be made chemical, electrical and mechanic. When the muscles are use many times to the maximum force, the muscle will decline. That decline is called muscle fatigue.…

    • 497 Words
    • 2 Pages
    Improved Essays
  • Improved Essays

    Muscle Fatigue Analysis

    • 983 Words
    • 4 Pages

    Fatigued muscles contract weaker than rested muscles (Saladin, 2012). This is especially evident when maximum isometric force is measured in repeated tetani and reveals the there is an improved decline that is obvious even on the second tetanus of the series (Allen, Lamb, & Westerblad, 2008). Other parts of muscle performance are altered during fatigue. One such example is the shortening velocity reduction and the time course of slowed relaxation. Almost every activity that humans participate in depends on the power output of the muscles involved and, since power output is the result of both force and shortening velocity, the decrease in performance can be bigger than the decrease in isometric force (Allen, Lamb, & Westerblad, 2008).…

    • 983 Words
    • 4 Pages
    Improved Essays
  • Decent Essays

    M1 Somatotopic Map

    • 332 Words
    • 2 Pages

    1. The figure in the question shows the motor and sensory topographic organization through the use of a homunculus. The homunculus in the motor system figure is correct in both pathways due its somatosensory nature. There is evidence though that while this map technically is correct in broad terms, the M1 somatotopic map is much more complex and non-linear then this. It was originally thought that the motor system had sequential operations that were encoded at each step by a different neuronal population and its only role was that of which muscles to contract, when, and with how much effort.…

    • 332 Words
    • 2 Pages
    Decent Essays
  • Improved Essays

    Muscles Lab Report

    • 786 Words
    • 4 Pages

    One nerve cell can control lots of muscle fiber, they can form a motor unit. When we do muscle contraction, motor units are activated to send electron signal to muscles, then muscles can do contraction. According to the different physiological function, motor unit can be divided into 2 categories, kinetic motor unit and tonic motor unit. The high frequency of electron signal released when the motor unit of the muscle fiber is excited, the contraction force is strong, but is easy to fatigue, it is the fast fatigable motor unit. When the muscle fibers in the tonic motor unit are excited, the impulse frequency is low, but it can be released for a long time, it is slow oxidative unit.…

    • 786 Words
    • 4 Pages
    Improved Essays
  • Improved Essays

    Blood Supply P2

    • 1192 Words
    • 5 Pages

    During exercise you muscles will need more oxygen which carried in your blood stream. There will be more oxygen to be in use so vasodilation and vasoconstriction will have to…

    • 1192 Words
    • 5 Pages
    Improved Essays
  • Improved Essays

    Time To Task Failure

    • 589 Words
    • 3 Pages

    This evidence explained that the greater muscle mass involved in stronger person makes them to adapt with the time to failure. Next, Matkowski, Place, Martin, and Lepers (2011) further a study in comparing the different of unilateral and bilateral exercise on time to task failure and associated maximal voluntary contraction force performed on knee extensor muscle. The researcher found there is a significant different on time to task failure where the bilateral exercise were shorter as compared to unilateral exercise. However, the maximal voluntary contraction force and maximal voluntary activation losses were greater after a unilateral exercise as compared after a bilateral exercise. The reason behind this is due to the differences in the activation pattern, in muscle perfusion and/or in the muscle mass involved.…

    • 589 Words
    • 3 Pages
    Improved Essays
  • Decent Essays

    Muscle Contraction

    • 360 Words
    • 2 Pages

    For this, the head of the myosin binds to the troponin site of the actin filament. Then, an ATP molecule will bind to myosin to separate actin and myosin and thus allow its attachment to the neighboring troponin site due to hydrolysis of ATP in ADP + Pi. This creates a slippage of myosin fibers on the actin fibers and allows for muscle contraction.…

    • 360 Words
    • 2 Pages
    Decent Essays
  • Improved Essays

    Essay On Skeletal Muscle

    • 1270 Words
    • 5 Pages

    For example, when you think of moving your leg using your quadriceps, the brain directs a signal down a nerve cell to your quadriceps muscle to contract. The amount of muscle being contracted depends on the signal that the nerve sent. A muscle is consisted of a lot of conjoined cells called fibers. Imagine these fibers as elongated cylinders.…

    • 1270 Words
    • 5 Pages
    Improved Essays