Muscle lab report

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PC1001: Week 8 Skeletal Muscle Laboratory Marking Key Title: (1 mark)

Aim: Make sure you mention all components of the laboratory. (2 marks)

Introduction: (24 marks total) Your introduction should describe the physiological properties of skeletal muscle, excitation – contraction (EC) coupling and sliding filament theory. Define the “all or none” law governing a muscle twitch. Define: twitch, summation, tetanus, and fatigue. Cite references in text using the Harvard (Author‐date) or AMA/Vancouver (superscript number) referencing system (check JCU Library Libguides here (http://libguides.jcu.edu.au/referencing) if unsure). Write a sentence or 2 on these topics (figures / tables are also allowed): Describe Physiological properties of skeletal muscles: (4 marks) Describe EC coupling: (4 marks) Describe Sliding filament theory: (4 marks) Define all or none law: (2marks) Define twitch: (2 marks) Define summation: wave and recruitment: (4 marks) Define tetanus: (2 marks) Define Fatigue: (2 marks) Material and Methods: (2 marks) Quickly summarise the experimental set up here (it is OK to quote PC1001 Week 8 Laboratory Notes), a picture of the set up is also permitted.

Results: (40 Marks total, 5 exercises x 8 marks) Attach a copy of the completed Toad Skeletal Muscle Data Notebook at the end of this report and label it ‘Appendix 1’ Graph marking: 0.5 = correct graph type (bar, line etc) 0.5 = correct data plotted 2 = data plot on correct axis, axis labeled, correct units 1 = complete figure legend Table marking: may appear just in the appendix rather than a repeated table 1.5 = Complete table header (above table) 0.5 – Correct data (with units) Text: 2 marks for appropriate text describing each exercise, must refer to Figure / Table. EXERCISE 1: The effect of stimulus intensity on contraction force Draw a line graph of contraction force (Y) versus stimulus intensity (X), label it ‘Figure 1: Contraction force versus stimulus intensity’ Use the data from Table 1 of the Data Notebook. In words, describe what is happening to contraction force as stimulus voltage increases.

http://libguides.jcu.edu.au/referencing

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Table 1 may be here or in appendix 1.

EXERCISE 2: The effect of preload on muscle contraction force Draw a line graph of net twitch force (Y) versus preload force (X), label it ‘Figure 2: Net twitch force versus preload” Use the data from Table 3 of the Data Notebook. Can be a line graph or a scatter plot In words, describe what is happening to net twitch force as preload increases

Table 3 may be here or in appendix 1.

EXERCISE 3: The effect of stimulus frequency on contraction force Draw a bar chart of force of first and second peak (Y) versus stimulus frequency (X), label it ‘Figure 3: Effect of stimulus frequency on force of two consecutive contractions” Use the data from Table 4 of the Data Notebook. Cannot be a line graph In words, describe what is happening to force of the second peak as stimulus frequency increases. Table 4 may be here or in appendix 1.

EXERCISE 4: Tetanus Draw a line graph of maximum force (Y) versus stimulus interval (X), label it ‘Figure 4: Maximum force versus stimulus frequency” Use the data from Table 5 of the Data Notebook. In words, describe what is happening to force of the second peak as stimulus frequency increases. Table 5 may be here or in appendix 1.

EXERCISE 5: Muscle fatigue Draw a line graph of contraction force (Y) versus time since stimulation (X), label it ‘Figure 5: Contraction force versus time since stimulation” Use the data from Table 6 of the Data Notebook. In words, describe what is happening to force of contraction as the time since stimulation increases. Table 6 may be here or in appendix 1.

Discussion: (24 marks total) Answers the following questions in your discussion (questions (or #) can be repeated, or paragraph breaks use to define questions. Refer to figures and tables rather than inserting in discussion text.

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1. Describe why you observe a graded response to increasing stimulus intensity in light of the “all or none” law governing muscle contraction. 5 marks

2. Explain why muscle contracts more forcefully when stretched (ie when preload is increased) 5 marks 3. Mechanistically, what happens to the muscle at the highest preload forces? 4 marks 4. When the muscle was stimulated repeatedly, what happened the force of contraction? Explain the mechanism

behind this phenomenon. 5 marks 5. Explain why muscle fatigue occurs. How long was your preparation able to maintain a maximal contraction? Would

your results have differed if you were measuring from smooth muscle tissue? Why? What approach do working muscles use to delay the onset of fatigue? 5 marks

Conclusion: (2 marks) Make concluding statement of approximately 150-200 words to summarise the outcomes of laboratory. References: (5 marks) Include 5-10 references of at least 3 different types (textbooks, journal/review articles, reputable websites) to support your report. 1 - Consistent formatting 3 - Appropriate references (no generic web sites, eg: Wikipedia) all references referred to, all included in list. 1 - Appropriate in text referencing Any plagiarized section or report receives mark of zero Summary of Marking allocation for this laboratory report:

Title 1 Aim 2 Introduction 24 Materials and Methods 2 Results 40 Discussion 24 Conclusion 2 References 5 Total 100 (10% Final Assessment)

PC1001: Week 8 Skeletal Muscle Laboratory Marking Key

Title: (1 mark)

Aim: Make sure you mention all components of the laboratory. (2 marks)

Introduction: (24 marks total)

Results: (40 Marks total, 5 exercises x 8 marks)

EXERCISE 2: The effect of preload on muscle contraction force

EXERCISE 3: The effect of stimulus frequency on contraction force

EXERCISE 4: Tetanus

EXERCISE 5: Muscle fatigue

Discussion: (24 marks total)