TEST 6 Flashcards
The basic unit of contraction in a skeletal muscle is?
a) Myofibril
b) Sarcomere
c) Tendon
d) Myosin
Sarcomere
The ___________ is the contractile protein found in the thick filaments of a sarcomere.
a) Actin
b) Tropomyosin
c) Myosin
d) Troponin
Myosin
The _______ is a specialized endoplasmic reticulum found in skeletal muscle cells.
a) Sarcoplasmic reticulum
b) Golgi apparatus
c) Mitochondria
d) Nucleus
Sarcoplasmic reticulum
The _______ is a thin filament protein that covers the active sites on actin molecules in a relaxed muscle fiber.
a) Myosin
b) Tropomyosin
c) Troponin
d) Sarcomere
Tropomyosin
The __________ is the regulatory protein that binds calcium ions and initiates muscle contraction.
a) Actin
b) Tropomyosin
c) Myosin
d) Troponin
Troponin
The __________ is the region of a sarcomere where actin and myosin filaments overlap.
a) Z-line
b) M-line
c) H-zone
d) A-band
H-zone
The __________ is the protein that connects the Z-lines and helps stabilize the sarcomere during contraction.
a) Actin
b) Titin
c) Myosin
d) Nebulin
Titin
The __________ is the thin filament protein that anchors actin to the Z-line.
a) Tropomyosin
b) Myosin
c) Nebulin
d) Dystrophin
Tropomyosin
The __________ is the area in the center of the sarcomere that contains only myosin filaments.
a) I-band
b) H-zone
c) A-band
d) Z-line
H-zone
The __________ is the structure that connects the muscle to the bone.
a) Tendon
b) Ligament
c) Cartilage
d) Fascia
Tendon
The __________ is the neurotransmitter released by motor neurons to initiate muscle contraction.
a) Dopamine
b) Serotonin
c) Acetylcholine
d) Norepinephrine
Acetylcholine
The __________ is the structure where the motor neuron and muscle fiber meet.
a) Neuromuscular junction
b) Synaptic cleft
c) Sarcolemma
d) Sarcoplasmic reticulum
Neuromuscular junction
The __________ is the structural protein that surrounds individual muscle fibers.
a) Endomysium
b) Perimysium
c) Epimysium
d) Sarcolemma
Endomysium
The __________ is the plasma membrane of a muscle fiber.
a) Epimysium
b) Endomysium
c) Sarcolemma
d) Perimysium
Sarcolemma
The __________ is the functional unit of a muscle fiber.
a) Sarcomere
b) Myofibril
c) Sarcoplasm
d) T-tubule
Sarcomere
The __________ is the storage form of glucose in skeletal muscle.
a) Glycogen
b) Glucagon
c) Insulin
d) Glucose-6-phosphate
Glycogen
The __________ is the type of muscle fiber that is adapted for aerobic endurance activities.
a) Type I (slow-twitch)
b) Type IIa (fast-twitch oxidative)
c) Type IIb (fast-twitch glycolytic)
d) Type III (intermediate)
Type I (slow-twitch)
The __________ is the protein responsible for releasing calcium ions from the sarcoplasmic reticulum.
a) Actin
b) Tropomyosin
c) Myosin
d) Ryanodine receptor
Ryanodine receptor
The __________ is the energy molecule used by muscle fibers to power contraction.
a) ATP
b) ADP
c) AMP
d) GTP
ATP
The __________ is the enzyme that breaks down acetylcholine in the synaptic cleft.
a) Acetylcholinesterase
b) Monoamine oxidase
c) Cholinesterase
d) Adenosine triphosphatase (ATPase)
Acetylcholinesterase
The specific area on the muscle fiber where the motor neuron releases acetylcholine is known as the __________.
a) Sarcolemma
b) T-tubule
c) Sarcoplasmic reticulum
d) Synaptic cleft
Synaptic cleft
Acetylcholine binds to receptors on the __________, which triggers an electrical impulse in the muscle fiber.
a) Sarcolemma
b) T-tubule
c) Sarcoplasmic reticulum
d) Synaptic cleft
Sarcolemma
The electrical impulse generated in the muscle fiber travels deep into the muscle fiber via structures called __________.
a) Sarcomeres
b) Actin filaments
c) Myosin filaments
d) T-tubules
T-tubules
The presence of the electrical impulse in the T-tubules triggers the release of __________ from the sarcoplasmic reticulum.
a) Calcium ions
b) Sodium ions
c) Potassium ions
d) Chloride ions
Calcium ions