Control of Muscles Experiments Name:______
Control of Muscles Experiments Name:______
Ppt#3 Whole muscle Behavior A&P 11/2015
Procedures Part 1 – Experiment: Control of Muscles
Blink your eyes three times, then immediately begin holding your eyes open as long as you can. Do not roll your eyes around as
you hold them open. Have a friend time you.
• How long were you able to keep your eyes open without blinking? ______minutes _____ seconds
• Rest your eyes for at least five minutes with normal blinking and eye movement.
Try the experiment again. How long were you able to keep your eyes open? ______minutes _____ seconds
• Rest your eyes and try the experiment again. How long were you able to keep your eyes open?
______minutes _____ seconds
What is the average amount of time you can keep your eyes open? ______minutes _____ seconds
Compare your average to the average amount of time that other people in your class are able to keep their eyes open without blinking. Is there a significant difference? ______
If there is a significant difference, what do you believe could account for it?
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Analysis and Conclusions for Part 1– Experiment: Control of Muscles
1. What is a voluntary action? ______
______
2. List several examples of muscle actions that are voluntary.
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3. What is an involuntary action? ______
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4. List several examples of muscle actions that are involuntary.
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5. The reaction of blinking your eyes is stimulated when the surface of the eye begins to dry out. This action of blinking
your eyes is controlled by muscles.
Are the muscles that blink your eyes voluntary, involuntary, or both? ______
Why did you choose the answer you gave? ______
______
List several other actions that are controlled in the same way that eye blinking is. ______
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Background Material Part 2: Muscle Fatigue
Muscles work with the skeletal system to move parts of your body In order for the muscles to work, they must have a supply of sugar, which can be burned to provide energy However, when a muscle uses up its supply of available energy, it begins to ache and cramp rather than work properly. This cramping is called muscle fatigue. The better physical condition a person is in, the longer his or her muscles can work without experiencing muscle fatigue.
A bit more in-depth:
Skeletal muscles move the bones in the skeleton. When the muscles contract, it makes the joints able to move and lets us engage in physical activity of all kinds. Chemical energy is needed to cause muscles to contract. The chemical energy is a result of respiration. Skeletal muscle is made of two different kinds of fibers: fast twitch (FT) and slow twitch (ST). On the average, we have about half ST fibers and half FT fibers. However, elite athletes have different amounts of ST and FT fibers. Depending on their sport they may have much more of one type than the other.
Fast twitch fibers use up energy very quickly. The muscle fibers contract very fast. They are used in activities that that short, but intense. Stop-and-go, change-of-pace movements in many team sports depend on FT fibers. Sprinting and other quick, forceful movements also use the fast twitch fibers. Slow twitch fibers do not get tired as quickly. They are used during prolonged, low to moderate intensity activities. Athletes with good endurance and aerobic capacities, like marathon runners and cross-country skiers have very high percentages of ST fibers. The energy the muscles use comes from carbohydrates, fats and protein. Carbohydrates in the form of glucose are the main energy source for the body. Energy in the form of fat varies greatly in individuals, and is the next source of energy for the body. Protein is not stored for the purpose of creating energy; the function of protein is to build molecules in the body. However, when all other energy is used up, the body will use protein for energy. The brain also uses energy to stay alert and to help a person concentrate. The brain is fueled almost entirely by carbohydrates.
Procedure Part 2: Muscle Fatigue
You can do a very simple test to demonstrate muscle fatigue. Obtain a clothes pin that is held together with a metal spring. Hold the ends of the clothespin between the tips of your index finger and your thumb. Begin pinching the clothespin open and then allowing it to close slowly Continue this action as many times as possible, counting the number of times you can open the clothespin. Stop when the muscle between your thumb and index finger begins to cramp.
How many times were you able to open and close the clothespin? ______
Wait two minutes and try this test again. Repeat the test a total of five times, allowing a two-minute rest between each test. For each test, record the number of times you were able to open and close the clothespin. Record your results in the table.
Table of Muscle Fatigue
Number of Opening/closing
Test 1=
Test 2=
Test 3=
Test 4=
Test 5=
Analysis and Conclusions Part 2 : Muscle Fatigue
1. Make a graph that shows the number of times you were able to open and close the clothespin in each trial. Number of Openings for trials 1 2 3 4 5
Trial #1 Trial #2 Trial #3 Trial #4 Trial #5
2. What does your graph indicate about the onset of muscle fatigue with each succeeding trial?
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3. If a person is involved in some unaccustomed physical activity for several hours, what happens to his or her ability to
perform the activity?
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