Bi309 Lab-2: Effect of Temperature and Stimuli on Simple Muscle Twitch.

BI309 Lab-2

Name of student: Anisa Dreunibakarua
ID #: S11033198

Title: Effect of Temperature and Stimuli on Simple Muscle Twitch.

Introduction:
Skeletal muscle is a type of striated muscle that is attached to skeleton to facilitate movement by applying force to bones and joints through contraction. Skeletal muscle generally contract voluntarily when stimulated by the nerve, although they can also contract involuntarily at times.
Muscle action is controlled by the Nervous System. Nerves are in touch with muscle by motor end plates which convey a stimulus to contract.
Muscle activity is not always a smooth ride as it can be affected by its surrounding. Muscle tissues have its plasticity nature, in which case it has to adapt to its surrounding environment and activity that it carries out daily. Different environmental temperature and work intensity can influence the nature or physique of a muscle tissue.
In this Laboratory activity, the gastrocnemius muscle tissue of a toad was observed under different temperature and influence of different stimulus.
The Contration phase, relaxation phase and peak of contraction of all stimuli will be compared and contrasted.

Material and Methods: As per the lab handout

Results:

Discussion of results-

In a simple muscle curve (such as fig1) there are five points that indicate the changes of different phase. Point A is the point of stimulation. Point B is the beginning of contraction. Point C’ is the amplitude of muscle contraction. Point C is the relaxation of the muscle. Point D is the end of muscle contraction and relaxation. There are 3 different phases observed between these points in this simple muscle curve. From Point A-B is the Latent period. Point B-C is the Contraction period. Point C-D is the relaxation period. While point C’ shows the strength of muscle contraction. With the test of different temperature (as in fig 2,3 and 4) it is observed that as the temperature increases from 10oC to 35oC,the latent period, the contraction period and relaxation period decreases, while the height of the contraction increases. The Decrease in latent, contraction and relaxation period decrease due to increased rate for muscle activity.
The height of the contraction period increase due to increase of muscle strength. At the temperature of 10oC the muscle contraction phase and relaxation phase is longer than the normal room temperature. Due to this most athletes have ice bath as part of their recovery program after extensive exercise. This allows their muscle to cool and be more relaxed.
For the effect of excessive temperature, the muscle was exposed to rigor salt solution of 1000C. It could be depicted form the result (such as fig 5) that the contraction period was quite short due to increase in energy for muscle activity, and the muscle did not go through the relaxation period as the protein must have been denature resulting in a dead muscle tissue.

In Figure 6 the stimulation of a muscle twitch is observed. In this case there are two consecutive twitches. It is observed that the curve resulting from the first twitch is shorter than that of the second twitch. In such case the second twitch benefit from the energy from the first twitch. This could be compared to a marathon athlete’ muscles, when the muscle is already psyched for a long distance event.
During the first few rounds of the run the muscle will be psyched and will increase in momentum till the last round.

The curve of muscle contraction of Genesis of Tetanus shown in Figure 7, reveals that the starting point of muscle stimulation is till the time taken to reach the maximum peak of muscle contraction is very short. The contraction and relaxation of the muscle is occurring at a constant rapid rate, where the muscle does not fully relax at the end of each cycle.
Toward the end of the activity the peak of muscle contraction is shorter due to muscle fatigue. In such case it can be compared to an athlete participating on a vigorous exercise or running on a track event.
5) Identify 2 research articles on skeletal muscle contraction and incorporated the important findings to your results. Ohta,Y(et al 2010) studied the summation effect of contraction of human skeletal muscle. They noticed that the difference in the amplitude of a single pulse and two pulse train. Their results suggest that the acceleration peak is inversely proportional to the time taken to which acceleration peak is achieved.
According to the experiment carried out, this was true to the fact that the second wave or curve in a double stimulation is always greater than that of the first one. The second peak has a beneficial effect from the first peak. Secondly if the time taken for the acceleration to reach its highest peak is small, the acceleration peak will be high.

Barbra C ( et al 2008) studied the effect of Temperature on cross-bridge properties in intact frog muscle fibers. Their main observation was to correlate the relationship of the properties of frog muscle fibers contraction with increasing temperature.
In comparison to the lab experiment the relationship showed that as temperature increases, the muscle contraction peak increases while the contraction and relaxation period decreases.

Conclusion:
On the completion of this lab activity I was able to relate the effect of temperature on muscle activity. As an athlete I am able to understand how I benefit from regular exercise and being able to grasp the concept to the important of ice bath after some period of time of extensive exercise and training.

As temperature increases, muscle contraction is faster and stronger. Regular exercise can contribute to the flexibility of the muscle tissue and gain in momentum of muscle contraction. .

References: * Ohta.Y, Shima.N, Yabe.K.(2010). The effect of Summation of Contraction on Acceleration Signal in Human Skeletal Muscle. Department of Sport Sciences, Japan Institute of Sports Science,3-15-1

* Colombinim.B, Nocella.M, Benelli.G, Giovanni.C,and Bagni.M.A.(2008). Effect of temperature on cross-bridge properties in intact frog muscle fibers. Departimento di Scienze Fisiologiche and Istituto Interuniversitario di Miologia. Unicersita degli Studi di Firenzem Firenze, Italy.

References: * Ohta.Y, Shima.N, Yabe.K.(2010). The effect of Summation of Contraction on Acceleration Signal in Human Skeletal Muscle. Department of Sport Sciences, Japan Institute of Sports Science,3-15-1 * Colombinim.B, Nocella.M, Benelli.G, Giovanni.C,and Bagni.M.A.(2008). Effect of temperature on cross-bridge properties in intact frog muscle fibers. Departimento di Scienze Fisiologiche and Istituto Interuniversitario di Miologia. Unicersita degli Studi di Firenzem Firenze, Italy.