Worksheet 9 (11-7 to 11-11) Muscles
1. A single muscle cell is a
A) Fasciculus
B) Sarcomere
C) Myofiber
D) Myofibril
2. Most of the interior of muscle fibers are filled with these; which extend from one end of the muscle fiber
to the other.
A) Myofibrils
B) Nuclei.
C) Sarcoplasm.
D) Sarcoplasmic reticulum
3. What is the functional and contractile unit of a muscle? (Segment from one Z disk to the next)
A) Fascicle
B) Sarcomere
C) Myofibril
D) Sarcoplasm
4. Thin reticular connective tissue that covers each (individual) muscle cell
A) Endomysium
B) Perimysium
C) Epimysium
5. Connective tissue sheath that covers a fascicle (bundle of muscle fibers)
A) Endomysium
B) Perimysium
C) Epimysium
6. Connective tissue sheath that covers the entire muscle like an overcoat. (Hint: what Epidermis is to skin)
A) Endomysium
B) Perimysium
C) Epimysium
7. Thin myofilament which resembles two strands of pearls twisted together and provides a binding site for
myosin
A) Actin
B) Myosin
C) Troponin
D) Tropomysin
8. A regulatory protein attached to actin which provides a binding site for calcium
A) Actin
B) Myosin
C) Troponin
D) Tropomysin
9. Thick myofilament who’s head contains 2 globular subunits that will attach to actin to form a cross bridge
necessary for a muscle contraction.
A) Actin
B) Myosin
C) Tropomysin
10. The part of the myofibril that contains only actin myofilaments
A) Z disk
B) A Band
C) H Zone
D) I Band
11. Part of the myofibril where actin and myosin overlap
A) Z disk
B) A Band
C) H Zone
D) I Band
12. ________ is the cell membrane of a muscle fiber and the cytoplasm is called _________.
A) Sarcolemma / Sarcoplasm
B) Sarcolemma / Sarcoplasmic Reticulum
C) Sarcoplasm / Cisternae
13. Channels that transvers the muscle fiber that carry electrical signals from the cell surface to its interior
are called.
A) Terminal Cisternae
B) Triads
C) T-tubules
D) Axons
14. Sac-like regions of the sarcoplasmic reticulum that contain calcium ions that bind T-tubules
A) Terminal Cisternae
B) Triads
C) Transverse or T-tubules
D) Axons
15. A T-tubule surrounded by 2 terminal cisternae forms a
A) Sarcomere
B) Triad
C) Aponueroses
D) Synaptic Cleft
16. Muscle contraction theory in which the H and I band shorten to pull Z disks toward the center of the
sarcomere. (Note: the A band size will remain unchanged)
A) Contracting sarcomere Theory
B) Action Potential Theory
C) Sliding Fiber Theory
D) Sliding Filament Theory
17. Nerve cell that carries action potentials to skeletal muscle fibers is
A) Motor neuron
B) Afferent neuron
C) Motor unit
D) Synaptic vesicle
18. The point where the motor neuron axon and muscle cell meet; site where an action potential is created
A) Neuromuscular junction
B) Motor end plate
C) Motor Junction
19. The space between the presynaptic terminal and the muscle fiber membrane is called the
A) Neuromuscular Junction
B) Motor End Plate
C) Motor end plate
D) Synaptic cleft
20. Neurotransmitter released from the synaptic vesicles of the presynaptic terminal
A) Norepinephrine
B) Acetylcholinesterase
C) Acetylcholine
D) Synaptic Fluid
When a muscle cell is stimulated, ____________(Na+) gates open causing sodium to move into the
cell. This movement causes ____________________ of the cell (the inside becomes more positive).
Then; the sodium gates close and the ____________________(k+) gates open causing potassium to
move out of the cell. This movement causes _____________________ of the cell (the outside
becomes more positive). The cell process of depolarization and repolarization is called an
___________ _________________. Directly following the action potential, an active transport
pump restores the ion balance and returns the cell to its normal _______________________
________________ (resting membrane potential).
WORD BANK
Sodium Potassium
Depolarization
Repolarization
Action Potential
Transmembrane Potential