YOUR CONTRACTING MUSCLES: WORKSHEET
Use your notes, textbook or other sources to answer the following questions.
PART A: Multiple choice
1. Which of the following is not a function of the muscular system?
a) movement
b) posture c) movement inside intestines
d) production of heat
2. All of the following groupings are correct except:
a) cardiac, striated, voluntary
b) skeletal, striated, voluntary
c) smooth, nonstriated, involuntary
d) skeletal, nonstriaetd, voluntary
3. Striations are present in which of the following:
a) cardiac muscle b) smooth muscle c) both a and b
d) neither a or b
4. Which of the following is the term for the muscle cell membrane?
a) sarcoplasm
b) sarcoplasmic reticulum
c) sacromere
d) sarcolemma
5. In a sacromere, which of the following is found in the H band?
a) thick myofilaments
b) thin myofilaments
C) both of the above
6. What is stored in terminal cisterns?
a) sodium
b) calcium
c) potassium
d) magnesium
7. Where is myosin found in skeletal muscle cells?
a) in thin filaments
b) in thick filaments
c) in sarcoplasmic reticulum
d) in transverse tubules
8. The term referring to a muscle’s ability to shorten in length is:
a) irritability
b) contractibility
c) extensibility
d) conductivity
9. ______ refers to a muscle’s ability to respond to a stimulus.
a) irritability
b) contractibility
c) extensibility
d) conductivity
10. The sheath of connective tissue that envelopes the entire muscle is the ___.
a) perimysium
b) epimysium
c) endomysium
d) sacrolemma
PART B: SHORT ANSWER
1. According to the sliding filament theory, when a muscle cell contracts, the _______________
filaments slide past the ___________ filaments and the ____________ shortens.
2. List the six most important chemicals involved in muscle contraction.
3. a. What are the two parts to a myosin molecule?
b. Which part moves providing the power stroke for muscle contraction?
c. Which part of the myosin molecule has a hinge which allows vertical movement so that the crossbridge
can bind to actin?
4. What two important binding sites are found on the cross bridges (heads) of myosin?
5. What three protein molecules are the thin filaments made of?
6. What is the function of tropomyosin?
7. What is the function of troponin?
8. What causes the tropomyosin to move away from the myosin binding sites on the actin?
9. a) Which of the following will attach to myosin?
actin
tropomyosin
troponin
ATP
calcium ions
b. Which of the following will attach to actin?
actin
tropomyosin
troponin
ATP
calcium ions
c. Which of the following will attach to troponin?
myosin
tropomyosin
actin
ATP
calcium ions
10. What causes the release of calcium ions into the cytosol from the terminal cisternae?
11. What causes the myosin binding sites on actin to be exposed?
12. What is it called when the cross bridge flexes, pulling the filament inward toward the center
of the sarcomere?
13. What happens to the myosin head (cross bridge when the power stroke occurs)?
14. During the contraction of a muscle cell, what is happening to
a. the length of the sarcomere?
b. the position of the Z lines with respect to one another?
c. the length of the thin filament?
d. the length of the thick filament?
e. the width of the H zone?
15. Describe how muscle fibres react to exercise (p.42).