Assinment: Skeletal Muscle Laboratory Marking Key
Aim: Make sure you mention all components of the laboratory.
Introduction:
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. Write a sentence or 2 on these topics (figures / tables are also allowed):
Describe Physiological properties of skeletal muscles: Describe EC coupling:
Describe Sliding filament theory: Define all or none law:
Define twitch:
Define summation: wave and recruitment: Define tetanus:
Define Fatigue:
Material and Methods:
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:
Attach a copy of the completed Toad Skeletal Muscle Data Notebook at the end of this report and label it ‘Appendix 1'
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.
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:
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.
1. Describe why you observe a graded response to increasing stimulus intensity in light of the "all or none" law governing muscle contraction.
2. Explain why muscle contracts more forcefully when stretched (ie when preload is increased).
3. Mechanistically, what happens to the muscle at the highest preload forces?
4. When the muscle was stimulated repeatedly, what happened the force of contraction? Explain the mechanism behind this phenomenon.
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?
Conclusion:
Make concluding statement of approximately 150-200 words to summarise the outcomes of laboratory.
References:
Include 5-10 references of at least 3 different types (textbooks, journal/review articles, reputable websites) to support your report.
1 - Consistent formatting
2 - Appropriate references (no generic web sites, eg: Wikipedia) all references referred to, all included in list. 1 - Appropriate in text referencing.
https://www.dropbox.com/sh/56v3rhud1i4zd22/AAA90bQqdfQH5c5jt8UBm5Sta?dl=0
Attachment:- Generic_Lab_Report_Guidelines.pdf