Download INTRODUCTORY LAB REPORT

BIOL 260 REPORT #3: MUSCLES (20 points)
Team Names: _____________________
A Note Regarding Lab Reports:
1. ALL group members must contribute equally to all aspects of the report (performing experiments, writing, and
final editing), and all members must be ALLOWED to contribute equally to all aspects of the report.
2. Percent (%) contribution of each group member should be specified (especially if not equal to the others), & signed.
3. Report should be finished and be submitted to ALL group members for FINAL EDITING at least 24 hours before
turning it in during your weekly lab time.
PART 1: WHOLE MUSCLE CONTRACTION (10 points)
1. With reference to Activity 1 of the BioPac Electromyography (EMG) Lab, state your complete
hypothesis (including dependent and independent variables), for Activity 1. What are your predictions
if your hypothesis is true? What do you predict if you hypothesis is false?
2. Refer to the Electromyography lab. (a) Construct an XY-line graph from Table 1 to compare how
variable forces affect Integrated EMG (to show the correlation between Force and EMG; Plot EMG vs.
FORCE!! Which should be on the X or Y axis??  ). Plot the results from both forearms on the same
graph. Include a full caption for the graph, that briefly describes the conditions of the experiments, and
briefly summarizes the main outcomes. (b) In a few sentences, describe what can you conclude about
the performance of both arms. Are they fairly evenly matched? Explain why or why not you think
differences exist or not.
3. (a) What specifically is occurring in a muscle when you observe increased EMG activity? (think about
what is ACTUALLY being measured!) (b) Students often find that for any given force, one forearm
requires more EMG activity to generate the same amount of force as the other forearm. How might you
account for such a difference? (Assume that both forearms have the same total number of fibers and
motor units.)
4. Recall the IP exercise: Contraction of Motor Units quiz in which you manipulated the size of motor units
in the legs and arms of a basketball player. Some combinations resulted in blocking of the ball, others
in overshooting, and one in making a basket. (a) From what you’ve learned in these lab activities,
explain why the specific combination of motor units was required to generate the necessary force and
precision to make the shot. (b) Why were the other combinations not successful? (Remember: motor
unit size is NOT the same thing as muscle size.)
In the PhysioEx 9.0 Simulations, focus on Exercise 2: Skeletal Muscle Physiology, Activities 1-6, and
answer the following Review Questions: You may save and submit this part of the Lab Report pdf with your
report, or directly type it into this Report Template DOC file.
5. Activity 1: Muscle Twitch and the Latent Period. Answer Review Questions 3-5. You may save and submit this
part of the Lab Report pdf with your report, or directly type it into this Report Template DOC file.
a. Describe the process of excitation-contraction coupling in skeletal muscle fibers.
b. Describe the three phases of a skeletal muscle twitch.
c. Does the duration of the latent period change with different stimulus voltages? How well did the results
compare with your prediction?
6. Activity 2: Effect of Stimulus Voltage on Skeletal Muscle Contraction. Answer Review Questions 1-3.
Save and submit with your Lab Report.
a. Describe the effect of increasing stimulus voltage on isolated skeletal muscle. Specifically, what
happened to the muscle force generated with stronger electrical stimulations and why did this change
occur? How well did the results compare with your prediction?
b. How is this change in whole-muscle force achieved in vivo?
c. What happened in the isolated skeletal muscle when the maximal voltage was applied?
Rpt_muscles.doc
1
Revised 6.28.17 NCS, DJH
BIOL 260 REPORT #3: MUSCLES (20 points)
Team Names: _____________________
7. Activity 3: Effect of Stimulus Frequency on Skeletal Muscle Contraction. Answer Review Questions 2,
3, & 5. Save and submit with your Lab Report.
a. In this experiment you observed the effect of stimulating the isolated skeletal muscle multiple times in a
short period with complete relaxation between the stimuli. Describe the force of contraction with each
subsequent stimulus. Are these results called treppe or wave summation?
b. How did the frequency of stimulation affect the amount of force generated by the isolated skeletal muscle
when the frequency of stimulation was increased such that the muscle twitches did not fully relax between
subsequent stimuli? Are these results called treppe or wave summation? How well did the results
compare with your prediction?
c. Compare and contrast frequency-dependent wave summation with motor unit recruitment (previously
observed by increasing the stimulus voltage). How are they similar? How was each achieved in the
experiment? Explain how each is achieved in vivo.
8. Activity 4: Tetanus. Answer Review Questions 1 & 3. Save and submit with your Lab Report.
a. Describe how increasing the stimulus frequency affected the force developed by the isolated whole
skeletal muscle in this activity. How well did the results compare with your prediction?
b. Beyond what stimulus frequency is there no further increase in the peak force? What is the muscle
tension called at this frequency?
9. Activity 5: Fatigue. Answer Review Questions 2-4. Save and submit with your Lab Report.
a. What are some proposed causes of skeletal muscle fatigue?
b. Turning the stimulator off allows a small measure of muscle recovery. Thus, the muscle will produce more
force for a longer time period if the stimulator is briefly turned off than if the stimuli were allowed to
continue without interruption. Explain why this might occur. How well did the results compare with your
prediction?
c. List a few ways that humans could delay the onset of fatigue when they are vigorously using their skeletal
muscles.
PART 2: MUSCLE METABOLISM & FATIGUE (5 points)
10. Refer to the data in Table 2 of your lab manual and construct a single GRAPH containing all related
data sets. How did the results compare to the hypothesis you wrote in the lab manual? Discuss and
explain any differences you observed in the endurance of your two forearms. Include quantitative data
in your explanation.
Hint: just because you may be “right handed” doesn’t necessarily mean your right hand is stronger.
Consider what sorts of activities you engage with your right compared to your left. Are these
anaerobic or aerobic activities?
11. Refer to IP: Sliding Filament Theory and (a) identify all the sources of ATP that were used by your
muscle during the endurance test. (b) Identify all of the roles (functions) ATP plays in muscle activity.
(c) What is occurring as your muscle fatigues? (d) What physiologic factors within the muscle might
affect your time to fatigue?
12. Describe the physiologic processes that occur within a muscle and its myocytes when you are
repaying your oxygen debt.
Rpt_muscles.doc
2
Revised 6.28.17 NCS, DJH
BIOL 260 REPORT #3: MUSCLES (20 points)
Team Names: _____________________
PART 3: INVESTIGATIVE WORK (6 points)
13. Experiment 6, Activity 2: EMG Investigation: With reference to your planned EMG Experiment, Report
the hypothesis you proposed and identify the predicted results..
a. Hypothesis (including dependent and independent variables):
i.
Predicted results if hypothesis is true:
ii. Predicted results if hypothesis is false:
b. Methods: (insert your actual experimental protocol here)
c. Results: (briefly describe [do not explain] your results here; insert appropriate graphs, with captions)
d. Discussion: (insert your analysis/explanation of the results and your conclusions here). Interpret and
explain the meaning of your data. Indicate whether the results support your hypothesis. If they
do not, describe what further experiments would need to be done to clarify the issue.
14. Include the summary (500 words) of your literature research on muscle physiology. Summarize the
background and hypothesis, very briefly describe what was done, and summarize the major
conclusions. Cite your source using APA style.
 Suggestions for topics: (be sure to use a professional, PRIMARY literature source – with actual
experiments and data to review! See “Literature Research” guide in WebAccess):
a. Sources of muscle fatigue
b. Factors affecting post-exercise recovery of muscle function
c. Diseases that affect muscular function or development: Muscular Dystrophy, tetanus,
botulism, paralytic shellfish poisoning (red tides), etc.
d. Causes of muscular soreness
e. Can muscles and tendons (and bones) be strengthened, and how much so, by “high
impact/contact” athletic training: eg -- martial arts, football, rugby, etc.
f. Any interesting and relevant topic you find on muscle FUNCTION.
*** See further instructions for making this report the main entry for your Biology Program e-Portfolio.
Rpt_muscles.doc
3
Revised 6.28.17 NCS, DJH