Trial 1 | Trial 2 | Trial 3 | Trial 4 | Trial 5 | |
| Predicted Value | |||||
| Actual Value |
Post-Lab Questions
1. How did the predicted results compare to the actual results?
2. Did you notice any changes in the number of repetitions you could perform, or how your hand felt after each of the trials?
3. Explain the actions that were occurring at the cellular level to produce this movement. Include sources of energy and any possible effect of muscle fatigue.
4. Hypothesize what would happen if blood flow was restricted to the hand when this experiment is performed.
Experiment 4: Gross Anatomy of the Muscular System
Muscle actions are often described as a departure of the from the anatomical position of the body. In performing the next exercise, you will understand how muscles act to affect motion.
| Materials*Participant (can be yourself) *Heavy Object (approximately 5 pounds) | *You must provide |
Procedure
1. Begin by examining muscles found in the upper limbs. First, extend your forearm so you have a clear view of your hand. What muscle is required to perform this extension? Extend your fingers out so they are straight and splayed apart. Then, retract your fingers into a tight fist. Repeat this motion several times, observing the wrist and hand muscles as the flex and relax. What muscles are used to complete this action? Record your observations in Table 2.
Note: It is helpful to palpate the area being flexed to better identify which muscles are being used.
2. Moving up the limb, extend your forearm out until it is parallel to the ground. Have a partner press down on your forearm. Flex your forearm to provide resistance as your partner pushes down. Observe the forearm and identify which muscles are being used. Record your observations in Table 2.
3. The partner should stop pushing down on your forearm, but keep it extended. Curl the forearm upward, creating a bend at the elbow. Observe which muscles are being used to complete this action, and record your observations in Table 2.
4. Find a heavy object, and pick it up. Keeping your arm straight, raise the object out to the side until it is parallel to the ground. What muscles does this require? Continue holding the object, and extend your arm back behind you. What muscles does this activate? Record your observations in Table 2.
Note: Be sure the heavy object is not too heavy before you lift it. This item should be approximately 5 – 10 pounds. This object should never be raised above your head!
5. Move down to the lower limbs, and determine what motions are needed to view the lower limb muscles in action. For example, you may want to walk, jump, sit, point your toes, etc. Engage at leave seven different muscles and indicate what motion was used to engage each muscle in Table 2.
| Table 2: Gross Anatomy Data | ||
| Movement | Muscle(s) Activated | Action(s) of Muscle(s) |
| 1. Forearm Extended (Step 1) | ||
| 2. Fingers Extended and Splayed (Step 1) | ||
| 3. Fingers Retracted (Step 1) | ||
| 4. Forearm Pressed Down Upon (Step 2) | ||
| 5. Elbow Bent (Step 3) | ||
| 6. Arm Raised to Side with Heavy Object (Step 4) | ||
| 7. Arm Extended Back with Heavy Object (Step 4) | ||
| 8. (lower limbs; student selects action…) | ||
| 9. (lower limbs; student selects action…) | ||
| 10. (lower limbs; student selects action…) | ||
| 11. (lower limbs; student selects action…) | ||
| 12. (lower limbs; student selects action…) | ||
| 13. (lower limbs; student selects action…) | ||
| 14. (lower limbs; student selects action…) |
Post-Lab Questions
1. Label the human muscle diagram.
2. Which muscle(s) were used to extend your arm backwards?
3. Which muscle(s) were used to extend and splay your fingers outward?
