Activity 1: Muscle Twitch and the Latent Period
Muscles have different functions in our body. They maintain body temperature by contracting, and they use the energy stored in the body, which later is transformed into heat. For muscles to contract, they must be stimulated by motor neurons; these motor neurons meats at the neuromuscular junction. When the nerve impulses reach the neuromuscular junctions voltage –regulated calcium channels open and allow calcium to enter the axon; the ca2+ inside cause’s vesicles to fuse with an axonal membrane causing it to release ACH via exocytosis. The ACH then binds to its receptors in the sarcolemma and causes an action potential in the muscle. Binding of ACH to its receptor opens chemically gated channels; …show more content…
Next, I increased the voltage is 0.2, and then I stimulated the muscle and observe the results. I continue increasing the voltage gradually by 0.1 until the minimum voltage required was generated. Lastly, the voltage was increased by 0.5 and I kept on stimulating the muscle until the voltage reached the voltage of 10.
Table 1: Activity one: Muscle Twitch and Latent Period
Voltage Length Active Force Passive Force Total Force Latent Period
0.0 75 0.0 0.0 0.0 …..
3.0 75 1.04 0.0 1.04 …..
4.0 75 1.32 0.0 1.32 3.20
6.0 75 1.65 0.0 1.65 3.20
8.0 75 1.81 0.0 1.81 3.20
10.0 75 1.82 0.0 1.82 3.20

Results
When the voltage was set at zero the muscle did not contact and there was no Excitation-Contraction Coupling. On the other hand, with a voltage of 3.0, the active forces were generated but the latent period was not recorded. From the voltage of 4 to 10.0 the Excitation-Contraction Coupling were developed and the latent period was equal.

Activity 2: The Effect of Stimulus Voltage on Skeletal Muscle Contraction
Voltage length Active force Total force
0.0 75 0.0 0.0
0.2 75 0.0 0.0
0.8 75 0.02 0.02
1.0 75 0.15 …show more content…
As I have mentioned in the introduction, motor unit consist of single motor neuron and the muscle cells. Activity 2 proved my hypothesis, which states that fewer stimuli requires very small amount of motor unit, while large stimulus requires greater motor unit. In this activity, the increase in stimulus increases muscle forces generated. This is because larger forces require greater motor units for contraction to happen. For example, we need fewer motor units when lifting a lighter object, but when forces of the object increases, greater number of motor units are required. This is so because with larger stimulus smaller motor unit cannot generate any muscles contraction. It requires couple of motor unit for a heavy object to be lifted. In activity 2 when the stimulus was increased, the larger numbers of motor unit were recruited; this is why contraction occurred. I also observed that when the required amount of motor unit were recruited, the activity remained constant. This shows that, when muscles are stimulated they require a certain amount of motor unit for contract to