What is the minimal, or threshold, stimulus? 0V. 2. What is the maximal stimulus? 10V. 3. How can you explain the increase in force that you observe? he increase is how many volts went into the muscle. Activity 4: Investigating Treppe 1. What happens to force production with each subsequent stimulus? It gets higher.
Activity 5: Investigating Wave Summation 1. Is the peak force produced in the second contraction greater than that produced by the first stimulus? yes 2. Is the total force production even greater? yes. 3. In order to produce smooth, sustained muscle contraction at Active Force = 2 gms, do you think you will need to increase or decrease the voltage? State your hypothesis. decrease. 4.
Test your hypothesis.At what voltage were you able to achieve Active Force = 2 gms? 2V. 5. How does the frequency of stimulation affect the amount of force generated by the muscle? Hint: Compare the force generated from a single click and from rapidly clicking Single Stimulus several times. It gets greater with each time. Activity 6: Investigating Fusion Frequency / Tetanus 1. Describe the appearance of the tracing.
It gradually goes up also forming hills. 2. How do the tracings change as the stimulus rate is increased? it is steeper and then it gradually becomes consistent. 3.From your graph, estimate the stimulus rate above which there appears to be no significant increase in force. 3 stimuli / sec. 4.
What stimulus intensity produced smooth force at Force = 2 gms? 2. 5V. 5. Which intensity produced smooth contraction at Force = 3 gms? 3. 6V. 6. Explain what must happen to the intensity and frequency of the stimulus to achieve smooth contraction at different force levels.
the force much almost match the v required to achieve smooth contractions. Activity 7: Investigating Muscle Fatigue 1. Why does the force begin to decrease with time?Note that a decrease in force indicates muscle fatigue. Because there is not enough ATP being produced to allow the muscle to contract that many times and for the length of time. 2. The muscle will produce force for a longer period if the stimulator is briefly turned off than if the stimulations were allowed to continue without interruption. Explain why.
Because for the brief time that the stimulation is off the muscle can produce more ATP to supply the contractions with. 3. Describe the difference between the current tracing and the myogram generated in step 6.The current tracing does not dip as much but gradually decreases as the muscle fatigues. Activity 8: Investigating Isometric Contraction 1. What happens to the passive force as the muscle length is increased from 50mm to 100mm? The passive force increases. 2.
What happens to the active force as the muscle length is increased from 50mm to 100mm? The active force increases until 74-76 then starts to decrease again.