lab report

Name _________________________________

Lab Report #8

I. Virtual Skeletal Muscle Electrical Simulation Lab

1. Complete the data table below (10 points)

Output Voltage (v)	Force Generated (grams)
0
.2
.4
.6
.8
1.0
1.2
1.4
1.6
1.8
2.0

2. Graph the data in the above table and include it here (10 points):

Output Voltage versus Force Generated (grams).

Assignment Questions: (5 points each numbered question)

1. What muscle is used in the experimental setup utilizing a frog muscle?

2. What was the purpose of the:

a) Electrode (3 points):

b) Transducer (3 points):

3. Based on the results of this experiment, what conclusions can you draw about the relationship between a muscle's workload and its threshold of stimulation?

4. What will happen if you increase the voltage stimuli after all motor units have been recruited?

II. Muscle Control

For this part of the lab exercise, you will need a timer or clock to do this exercise, or someone to help you that can record the time.

1. Rapidly blink your eyes four times. Then start the timer or note the time and hold your eyes open for as long as you can without blinking. Do not roll your eyes as you do this.

How long were you able to keep your eyes open without blinking?

_____min. ____seconds (1 point)

2. Now rest your eyes for 5-10 minutes, with normal eye movements including normal blinking. Then repeat the first experiment.

How long were you able to keep your eyes open this time without blinking? ______min. ____seconds (1 point)

3. Rest your eyes and repeat the experiment again.

Record the time that you were able to keep your eyes open without blinking for the third time. ____min. ___ seconds (1 point)

4. Calculate the average time that you can keep your eyes open. _________ (1 point)

· Is there a significant difference in these times? What do you think might account for this difference? (2 points)

· The reaction of blinking your eyes happens when the surface of your eye begins to get dry. This action is controlled by your muscles. Are the muscles that blink your eyes voluntary, involuntary or both? Explain. (4 points)

III. Muscle Fatigue

To do this exercise you will need any type of ball that you can squeeze like a tennis ball or a stress ball (not hard rubber or plastic, or one so soft it does not offer any resistance, etc.) or a clothes pin with a hinged spring. You will also need a timer/clock with a second hand. It may be easier if you also have a partner that can assist you.

1. You will either squeeze a ball as rapidly as you can and count the number of contractions for 15 second intervals for a total of 150 continuous seconds or open and slowly close a wooden clothespin with a metal spring for an equivalent amount of time. You will repeat this experiment 3 times waiting two minutes between each trial. If this causes your hand to cramp up at any time, stop.

Record the data below: (30 points)

Time Intervals	Trial #1 Number of contractions/openings	Trial #2 Number of contractions/openings	Trial #3 Number of contractions/openings
0 – 15 seconds
15-30 seconds
30-45 seconds
45-60 seconds
60 -75 seconds
75- 90 seconds
90-105 seconds
105-120 seconds
120-135 seconds
135-150 seconds

Calculate the average number of contractions/openings for each trial:

Avg. Trial #1 ____________ (2 points)

Avg. Trial #2 ____________ (2 points)

Avg. Trial #3 _____________(2 points)

What does this data tell you about the onset of muscle fatigue? (7 points)

Relate this information to someone who is performing some type of physical activity. What happens to this person’s ability to perform this task? (7 points)

This assignment must be completed by 11:59 PM ET Sunday evening