Looking at the events that lead to skeletal muscle contracti

Looking at the events that lead to skeletal muscle contraction: the somatic motor neuron has an action potential (AP) and slightly after that the skeletal muscle fiber has an AP. There is another time delay (the latent period) between the muscle fiber\'s AP and the mechanicat twitch. Summarize the events that occur between:^A the AP in the motor neuron and the AP in the muscle fiber and^B the AP in the muscle fiber and the mechanical twitch that account for these time delays between the events. TRUE or FALSE: Sarcomeres can change size without any actual shortening of the muscle cell. Briefly explain your answer. A study of world-class athletes found that many have tendinous (muscle) insertions that are farther from the joint than an average person. Explain why this trait would translate into an advantage for the athlete. Feel free to use a diagram.

Solution

4. Skeletal muscle contraction follows twitch, summation, and tetanus procedure. Latent period is the time frame between the stimulus to the motor nerve and the contraction of muscle. The process in between AP of neuron and AP of muscle starts when chemical synapse in between neuron and muscle transmits signal from neuron to muscle. When AP reaches to terminal bouton of chemical synapse, Ca2+ ions influx starts into the terminal. That influx causes the acetylcholine to fuse with membrane of neuron and activates the nicotinic acetylcholine receptors of the synapse. That causes the opening of sodium/potassium channel which turn the AP on in muscles.

5. It is true; during muscle isometric contraction the muscle cell cumulative contracts to create contraction pressure. Sarcomere achieves that contraction by increasing and decreasing the I-bands and the H-zone of sarcomere but the length of muscle will not change.

6. The tendinous insertion helps in forward flexion which will result into frequent movement of athletes\' body.