Question

9. Sarcomeres contain thin filaments of ________ and thick filaments of ________.
a.         creatine, adenosine
b.         hemoglobin, myoglobin
c.         troponin, tropomyosin
d.         actin, myosin

10. When stimulated by a muscle impulse, what do the terminal cisternae release into the sarcoplasm?
        A)    sodium ions, Na+
        B)    calcium ions, Ca2+
        C)    adenosine triphosphate, ATP
        D)    acetylcholine, ACh

11. In the sliding filament model, ________ stay in place and ________ are pulled toward the center of the
sarcomere.                                                                          
a. Z bands, A bands
b. muscle cells, myofibrils
c. thin filaments, thick filaments
d. myosin filaments, actin filaments

12. Skeletal muscle contractions are controlled by___ that stimulate or inhibit contraction of sarcomeres.                                                                                    
a. motor neurons
b. neuroglia
c. myoglobins
d. mitochondria

13. Calcium ions that cause sarcomeres to contract are stored in the ________.    
a. T tubule
b. sarcoplasmic reticulum
c. myofibril
d. motor neuron

14. Nerve impulses pass from a neuron to a muscle cell ________.         
a. across neuromuscular junctions
b. across a synapse
c. carried by neurotransmitters
d. all of the choices

15. In muscle contraction, calcium ions bind to ___, changing its shape and allowing cross-bridges to form.
a. ACh
b. myosin
c. actin
d. troponin

16. The connective tissue wrapping around a muscle that is continuous with tendons is the:
a.Perimysium
b.Endomysium
c.Epimysium
d.Ectomysium

17. When does a muscle develop oxygen debt?
a.when the supply of oxygen is inadequate to meet the demand of aerobic respiration
b.when lactic acid builds up in muscle tissue
c.when supplies of ATP are depleted
d.all of the above

18. A motor neuron and the muscle cells it synapses with form a ________.        
a. sarcomere
b. myofibril
c. synapse
d. motor unit

19. Rapid, repeated stimulation produces a sustained muscle contraction called ________.
a. muscle twitch
b. muscle tension
c. muscle tone
d. tetanus

20. Muscular dystrophies are genetic diseases in which ________.    
a. no motor neurons develop
b. muscle fibers break down and muscles progressively weaken
c. muscles stay contracted, sometimes fatally
d. muscles suddenly and involuntarily contract

21. Which of the following is NOT TRUE?
a All muscle tissue is contractile
b. Skeletal muscle is voluntary but smooth muscle is not
c. Superficial fascia holds skin to muscle
d. Muscles use the skeleton as leverage points as they push against bones to produce body
movement

22. Skeletal muscle is described by all of the following EXCEPT:
a.Striated
b.Voluntary
c.Multinucleate
d.Autorhythmic
e.Contractile

23. The walls of hollow organs and some blood vessels contain this type of muscle tissue.
a.Striated
b.Skeletal
c.Cardiac
d.Voluntary
e.Smooth

24. Which of the following is unique to cardiac muscle tissue?
a.Involuntary
b.Striated
c.Non-striated
d.Contains actin AND myosin
e.Contains intercalated disks

26. A muscle fascicle is a bundle of____surrounded by a membrane.
a. Myofibrils
b. Sarcomeres
c. Muscle Fibers
d. Muscles
e. Myofillaments

27. What actually shortens when a muscle fiber contracts?
        A)    thick and thin filaments
        B)    A bands, M lines, and Z discs
        C)    sarcomeres, H zones, and I bands
        D)    both b and c

28.Sarcoplasmic reticulum is the name given to which of the following?    
a.Rough endoplasmic reticulum in smooth muscle cells
b.Smooth endoplasmic reticulum in cells of the epimysium
c.Smooth endoplasmic reticulum in all muscle cells
d.Rough endoplasmic reticulum in cardiac muscle cells

29.Which of the following actions is caused by skeletal muscle?
a.Vasoconstriction
b.Vasodilation
c.Pupillary dilation
d.Eye movements
e.Heartbeat

30.Which of the following does NOT occur in a muscle during a contraction?
a.Thick and thin filaments interact
b.Muscle fibers stretch
c.Thick and thin filaments "slide" past one another
d.Muscle fibers shorten

31. A nerve impulse triggers the release of what chemical at a neuromuscular junction?
        A)    adenosine triphosphate (ATP)
        B)    acetylcholinesterase (AChE)
        C)    acetylcholine (ACh)
        D)    none of the above

32 .Rigor mortis demonstrates that skeletal muscle tissue
        A)    normally requires energy to end as well as to start a contraction
        B)    can survive and function for some time after the heart stops beating

        C)    maintains powerful contractions even with no ATP, until autolysis occurs
        D)    all of the above

36. A reduction in muscle size, tone, and power is called
        A)    atrophy
        B)    a spasm
        C)    hypertrophy
        D)    hyperplasia

37. Jogging, swimming, and aerobics all have this effect on skeletal muscle tissue.
a.Increased # of mitochondria per muscle cell
b.Increased # of muscle fibers
c.Increased # of motor units
d.Decreased # of skeletal muscle fibers
e.None of the above

Answer 1

Question 9- d. Actin and myosin

Explanation-Actin molecule are the major constituents of the thin actin filament. Each actin molecule is called F-actin and it is polymer of a small protein known as G-actin. Each F-actin molecules has an active site to which the myosin head is attrached.

Myosin filament are formed by myosin molecules. Myosin filament are thick filament wirh diameter of 115 Angstrom. These filament are situated in 'A' band.Each myosin molecule has two portions:

1. Tail portion.

2. Head portion.

Each myofibril consist of a number of two alternating bands which are also called sections. The two bands are

1. Light band or 'I' band .

2. Dark band or 'A' band.