Name:
Hour:
THE MUSCULAR SYSTEM I–
STUDYGUIDE ON MUSCLE TISSUE & THE MECHANISM
OF CONTRACTION
1. Fill in the chart below to compare and contrast the 3 types of muscle tissue.
Skeletal
Cardiac
Involuntary
Smooth
Striated
Uninucleate
Does not tire
Branching or figure 8 shape
2. Besides movement, what 3 other functions does the muscular system have?
a.
b.
c.
ANATOMY OF A SKELETAL MUSCLE:
3. What are the 3 connective tissue layers found in muscles?
4. Muscle is generally fragile and easily torn. What does the connective tissue provide to
help with this problem?
5. Which connective tissue ensheathes the muscle belly?
6. What is a fascicle?
7. Which connective tissue surrounds each fascicle?
8. Which connective tissue envelopes each muscle fiber?
9. The muscle fiber is essentially what structure?
10. Which of the 3 connective tissue layers is continuous with the tendon?
11. Each muscle fiber contains myofibrils. What are myofibrils?
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12. Label the diagram below with the following terms: epimysium, perimysium,
endomysium, muscle belly, fascicle, muscle fiber, myofibril, sarcomere.
13. The picture below shows the cross-section of an actual muscle. Do your best to label the
picture with the following terms: epimysium, perimysium, endomysium, muscle belly,
fascicle, muscle fiber. (You may want to circle certain parts while labeling in order to
correctly identify the structure.)
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MUSCLE CONTRACTION
14. Using an electron microscope, scientists have been able to see the inner workings of the
muscle fiber. Label the diagram below with the following terms: muscle fiber,
sarcolemma, sarcoplasmic reticulum, T-tubules (transverse tubules), mitochondria,
myofibril, sarcomere, Z-line, A-band, I-band, H-zone, actin, myosin.
15. What is a myofilament?
16. Which myofilament is thick?
17. Which myofilament is thin?
18. Which myofilament pulls the other in order to contract the muscle?
19. As muscle contracts, do Z-lines move closer together, farther away, or stay the same?
20. Which myofilament has regulatory proteins that prevent muscle contraction in a relaxed
muscle?
21. What are the names of these two regulatory proteins?
a.
b.
22. During contraction, what substance(s) will bind to the regulatory proteins to allow the
myofilaments to attach?
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23. Where is this substance stored in a relaxed muscle?
24. There is a sarcoplasmic reticulum and T-tubules (transverse tubules) that communicate
between the inner parts of the muscle cell and the sarcolemma. What is the sarcolemma?
25. A motor neuron is a specific kind of ________ cell that carries an impulse that tells
muscles to contract.
26. What is the neuromuscular junction?
27. The sarcolemma is affected by what neurotransmitter as it crosses the neuromuscular
junction from the motor neuron?
28. As this neurotransmitter binds to protein receptors on the sarcolemma, the sarcolemma
becomes permeable to what substance which is now allowed to rush into the muscle cell?
29. What charge does this substance have, negative or positive?
30. When sodium rushes into a cell, an action potential is created and it sweeps down the
entire length of the cell. This action potential also is carried into the inner part of the cell
by way of the T-tubules. Where will the action potential travel next?
31. In order to reverse this process and allow the muscle to relax again, what must happen?
a. Acectylcholine gets broken down by ____________________________.
b. Potassium (K+) moves into / out of the cell.
c. The sodium-potassium pump actively transports 3 __________ ions out of the cell
for every 2 _____________ ions that it pumps in, getting the cell ready for the
next contraction signal. Repolarizing the cell membrane.
d. As the relative charges of the cell are restored, _______________ is reabsorbed
into the sarcoplasmic reticulum and the ______________________________
complex binds to actin again in a way that prevents myosin from attaching.
e. The myofilaments slide away from each other and the muscle relaxes.
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