Activity 6: Investigating Fusion Frequency/Tetanus
Data: (add in EACH tracing you create here via screen shot or scanning data in)
Questions: ?answer each question; use full sentences; ask instructor if you need help
6-1: Describe the appearance of the tracing. Specifically, discuss the force appearance.
6-2: How do the tracings change as the stimulus rate is increased? Increased stimulation rate causes ___________ (increased, decreased, the same - choose one) active force; this is demonstrated by __________________ (smoother, rougher, the same - choose one) peaks shown on the tracings.
6-3: From your graph, estimate the stimulus rate above which there appears to be no significant increase in force: __________ stimuli/sec
6-4: What stimulus intensity produced smooth (active) force at Force = 2 gms? _______V
6-5: What intensity produced smooth contraction at Force = 3 gms? ________V
6-6: Explain what must happen to the intensity and frequency of the stimulus to achieve smooth contraction at different force levels. Increased stimulation rate creates _________________ (smoother, rougher, the same - choose one) contraction and decreased voltage means that _______________ (more, less, the same - choose one) force is produced.
Summary:
In this Activity, I learned/observed that: ? write 1-2 sentences on what you observed by doing this experiment – think “big picture”
Activity 7: Investigating Muscle Fatigue
Data: (add in EACH tracing you create here via screen shot or scanning data in)
Questions: ?answer each question; use full sentences; ask instructor if you need help
7-1: Why does the force begin to decrease with time? Note that a decrease in force indicates muscle fatigue. (Hint: think about what a muscle needs to contract).
7-2: Turning the stimulator off allows a small measure of recovery. 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.
7-3: Describe the difference between the current tracing and the myogram generated in step 6.
Summary:
In this Activity, I learned/observed that: ? write 1-2 sentences on what you observed by doing this experiment – think “big picture”
Activity 8: Investigating Isometric Contraction
Data: (add in EACH tracing you create here via screen shot or scanning data in)
Questions: ?answer each question; use full sentences; ask instructor if you need help
8-1: What happens to the passive and active forces as the muscle length is increased from 50 mm to 100 mm? Specifically, discuss what the force looks like at particular lengths - at what lengths did the force show large increases or decreases.
Passive force:
Active force:
Total force:
8-2: Explain the dip in the total force curve. (Hint: Keep in mind you are measuring the sum of active and passive forces).
Summary:
In this Activity, I learned/observed that: ? write 1-2 sentences on what you observed by doing this experiment – think “big picture”
Activity 9: Investigating the Effect of Load on Skeletal Muscle
Data: (add in EACH tracing you create here via screen shot or scanning data in)
Questions: ?answer each question; use full sentences; ask instructor if you need help
9-1: What do you see happening to the muscle during the flat part of the tracing? Click "Stimulate" to repeat if you wish to see the muscle action again.
9-2: Does the force the muscle produces change during the flat part of the tracing (increase, decrease, or stay the same)?
9-3: Which of the two weights used so far results in the highest initial velocity of shortening?
Weight_____ g
Velocity ______mm/sec
9-4: Repeat step 6 for the remaining two weights:
Weight _____g
Velocity_____ mm/sec
Weight _____g
Velocity _____mm/sec
9-5: What does the plot reveal about the relationship between resistance and the initial velocity of shortening? Increased resistance causes _________________ (shorter, longer, the same - choose one) initial velocity of shortening.
9-6: Describe the relationship between starting length and initial velocity of shortening.
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