Muscle Lab Report

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Lab Report Assistant
This document is not meant to be a substitute for a formal laboratory report. The Lab Report Assistant is simply a summary of the experiment’s questions, diagrams if needed, and data tables that should be addressed in a formal lab report. The intent is to facilitate students’ writing of lab reports by providing this information in an editable file which can be sent to an instructor.

Exercise 1: Muscle Twitch

Study the data for the three muscles in Tables 1A, 1B, and 1C.

1. Make a scatter plot graph in Microsoft Excel® using Data Tables 1A, 1B, and 1C that show the twitch tension timelines of the eye, rectus femoris, and plantaris muscle fibers. For each muscle, connect the dots together in sequence. Refer to the section in the Introduction of this lab manual titled: “Computer Graphing Using Microsoft Excel®” for help with this process.

2. Graph all three sets of data on one graph. Label the three muscles on the graph. Then, graph each muscle set on three separate graphs. Label the latent period, contraction phase and relaxation phase on the three separate graphs. Connect the dots of the scatter plot graph to make a line graph for each muscle.

Data Table 1A: Muscle twitch of the lateral rectus eye muscle|| Time
(milliseconds)|Tension
(kilogram-force)|
0|0|
1|0|
2|0|
3|10|
4|20|
5|30|
6|40|
7|30|
8|20|
9|10|
10|5|
11|2|
12|0|

Data Table 1B: Muscle twitch of quadriceps femoris||
Time
(milliseconds)|Tension
(kilogram-force)|
0|0|
3|10|
6|20|
9|30|
12|35|
15|40|
18|35|
21|30|
24|25|
27|22|
30|15|
33|12|
36|5|
39|0|

Data Table 1C: Muscle twitch of the plantaris||
Time
(milliseconds)|Tension
(kilogram-force)|
0|0|
5|5|
10|15|
15|20|
20|25|
25|30|
30|32|
35|36|
40|40|
45|38|
50|35|

55|32|
60|25|
65|22|
70|18|
75|15|
80|12|
85|10|
90|5|
95|3|
100|0|
Questions

A. What is a muscle twitch?
A muscle twitch is a small local involuntary muscle contraction and relaxation which may be visible under the skin or detected in deeper areas.

B. According to the graphs, which muscle has the fastest twitch? Why?

C. What is the latent period and why does it occur?Latent period is the time lapse that occurs between application of stimulus and its targeted effect. e.g when a nerve impulse arrives on a muscle fiber (stimulus), it takes a few milliseconds before the muscle begins to contract. It occurs because the metabolic machinery is at work. various preparatory processes are occuring.

Exercise 2: Treppe: The Staircase Effect

1. Data Table 2 shows muscle tension with increasing time. Observe the values in Data Table 2.

Data Table 2: Treppe||
Time
(milliseconds)|Tension
(kilogram-force)|
0|0|
3|2|
6|0|
9|4|
12|0|
15|8|
18|0|
21|10|
24|0|
27|12|
30|0|
33|15|
36|0|
39|15|
42|0|
45|15|
2. Create a scatter plot graph of the data from Data Table 2. Ensure that you connect the scatter plot dots to create a line graph for better visualization. Plot the time vs. tension in a Microsoft Excel® graph.

3. Use arrows to indicate where each subsequent stimulus occurred on the graph.

Questions

A. Why is treppe an important phenomenon for athletes to understand? The concept or phenomenon of "Treppe" occurs when a muscle contracts more forcefully after it has contracted a few times than when it first contracts. This is due to the fact that active muscles require decreasing degrees of succeeding stimuli to elicit maximal contractions. Returning to our example of the second set of squats feeling easier than the first, during the first set there was insufficient warm-up, and the second set felt easier because the first set actually served as a warm-up. The phenomenon in which the contraction strength of a muscle increases, due to increased Ca2+ availability and enzyme efficiency during...
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