28 Sep How do banding patterns change when a muscle contracts?

Pre-Lab Questions

1.            How do banding patterns change when a muscle contracts?

2.            What is the difference between a muscle organ, a muscle fiber, myofibril and a myofilament?

 

3.            Outline the molecular mechanism for skeletal muscle contraction. At what point is ATP used and why?

 

4.            Explain why rigor mortis occurs.

 

Experiment 1: Tendons and Ligaments

 

Post-Lab Questions

 

1.            Label the arrows in the slide images below based on your observations from the experiment.

 

A- chondrocytes

 

B- collagen

 

C- collagen fibers

 

 D- skeletal muscle fiber

 

E- Nuclei

 

F- Collagen fiber

 

2.            How does the extra cellular matrix of connective tissues contribute to its function?

 

3.            Why are tendons and ligament tissues difficult to heal?

 

4.            What difference do you see between the tendon – muscle insertion image and the tendon image?

 

5.            What differences do you see between the tendon and ligament sections?

 

Experiment 2: The Neuromuscular Junction

 

Post-Lab Questions

 

1.            Are there few or many nuclei at the end plate? There are many nuclei at the end plates.

 

2.            What is a motor unit?

 

3.            How is a greater force generated (in terms or motor unit recruitment)?

 

4.            What types of sensors are present within the muscle to identify how much force is generated?

 

Experiment 3: Muscle Fatigue

 

Table 1: Experimental Counts

 

                                                                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

 

Table 2: Gross Anatomy Data

 

Experiment 5: ATP and Muscle Fatigue

 

Table 3: Muscle Fatigue Data

 

Trial        Time (seconds)

 

Trial 1   

 

Trial 2   

 

Trial 3   

 

Post-Lab Questions

 

1.            What happened to the time intervals between Trial 1 and Trial 3? What caused this change?

 

2.            Identify three muscles which were engaged during the wall-sit.

 

3.            Explain the biochemical reasoning behind muscle fatigue.

 

Experiment 6: The Virtual Model – The Muscular System (Upper Body)

 

Post-Lab Questions

 

1.            What is the scientific term for the muscles of the mouth?

 

2.            Are the muscles used in deep mastication located on the ventral or dorsal side of the body?

 

3.            Do the m. pectoralis muscles belong to the deep thorax group or the superficial thorax group?

 

4.            Is the m. rectus abdominis or the m. obliques externus more deep within the body?

 

5.            Is the m. trapezius located in the abdomen, back, head, neck or thorax?

 

6.            Which muscle lies directly posterior to the m. serratus posterior inferior right and left muscle groups?

 

Experiment 7: The Virtual Model – The Muscular System (Lower Body)

 

Post-Lab Questions

 

1.            Is the extensor digitorum longus or the extensor digitorum brevis more superficial to the skin?

 

2.            How many adductor muscles exist within the body? List them here.

 

3.            Are the plantar muscles located in the foot, hip, leg, or thigh muscle group?

 

4.            Does the lateral group of muscles extend towards the hallus or the fifth toe? The fifth toe

 

5.            Which foot muscle group is most distal; the lateral group, the medial group, or the middle group?

 

Experiment 8: Virtual Model – Muscular System Coloring Activity

 

Upload images for each exercise below:

 

Abdomen:

 

 Back:

 

 Head:

 

 Upper Limb:

 

 Lower Limbs (Posterior):

 

 Lower Limbs (Anterior):

 

 Lower Limbs (Anterior – Distal):

 

Post-Lab Questions

 

1.            Describe the tissue that covers muscles.

 

2.            How many layers of abdominal muscle are there?

 

3.            What direction do the muscle fibers of the external oblique run?

 

4.            Why are muscle fibers considered excitable?

 

5.            Why is it important to have both flexors and extensors?

 

6.            How can muscle mass be influenced by training or age?