During muscle contraction, calcium ions bind to
Actin filaments
Myosin filaments
Troponin
Tropomyosin
Troponin
During muscle contraction, binding sites for myosin are uncovered by the movement of
Troponin
Tropomyosin
Actin myofilaments
ADP
Tropomyosin
What is released when myosin heads attach to actin filaments?
Phosphate
Tropomyosin
ADP
ATP
phosphate
The actin-myosin bond is broken by the attachment of
ATP
Phosphate
Tropomyosin
ADP
ATP
Energy produced when ATP is converted to ADP and phosphate is stored in
Myosin heads
Tropomyosin
Actin myofilaments
Troponin
Myosin heads
Cross bridges form between binding sites on actin myofilaments and
Calcium ions
Troponin
Myosin heads
Tropomyosin
Myosin heads
An action potential for a muscle cell is propagated along the
Sarcolemma
Sarcomere
Sarcoplasm
Tropomyosin
Sarcolemma
An action potential enters a muscle cell at the
Nucleus
Sarcomere
T-tubule
Actin myofilaments
T-tubule
Uncovering binding sites for myosin on actin myofilaments is involves troponin binding to
Tropomyosin
T-tubules
Calcium ions
Phosphate
Calcium Ions
Calcium ions released from the sarcoplasmic reticulum enter the
T-tubules
Sarcoplasm
Sarcolemma
Nucleus
Sarcoplasm
Movement of sodium ions into the muscle cell at the neuromuscular junction causes
Repolarization of the muscle cell membrane
Depolarization of the muscle cell membrane
Re-uptake of acetylcholine
Release of acetylcholine
Depolarization of the muscle cell membrane
Choline formed from the breakdown of acetylcholine in the synaptic cleft is
Ingested by macrophage cells in the synaptic cleft
Absorbed into the muscle cell
Concentrated and stored in the synaptic cleft
Resorbed by the presynaptic terminal membrane
Resorbed by the presynaptic terminal membrane
Increased calcium ion permeability of the presynaptic terminal cell membrane is caused by an
Sodium ions
Increased concentration of calcium ions
Action potential
Acetylcholine
Action potential
The neurotransmitter at the neuromuscular junction is
Calcium ions
Acetylcholine
Choline
Sodium ions
Acetycholine
The neurotransmitter at the neuromuscular junction increases permeability of the muscle cell membrane to
Sodium ions
Phosphate
Choline
Calcium ions
Sodium ions
Myofibrils are composed of protein filaments called actin and myosin.
True
False
true
A bundle of muscle fibers is known as a
Sarcomere
Fascicle
Myofibril
Myofilament
Fascicle
A skeletal muscle fiber (cell) contains a single nucleus.
True
False
False
The muscle cell membrane is called the
Endomysium
Neurolemma
Sarcomere
Sarcolemma
Sarcolemma
Which connective tissue wrapping separates individual muscle fibers?
Perimysium
Epimysium
Superficial fascia
Endomysium
Endomysium
In a fully contracted sarcomere, the actin myofilaments
Disappear
Form a Z disc
Overlap
Form the H zone
overlap
In a fully contracted sarcomere, the H zone
Is unchanged from a relaxed sarcomere
Disappears
Becomes the total width of the sarcomere
Is widest
Disappears
The I-band of a sarcomere is widest when a muscle is relaxed.
True
False
True
Which region of the sarcomere does not change length between muscle relaxation and muscle contraction?
I band
Z disc
A band
H zone
A band
The area between two Z discs is termed a(an)
A band.
I band.
sarcomere.
H zone.
Sarcomere