CORRECT WELL DETAILED ANSWERS|LATEST
UPDATE!!!!2025/2026|GUARANTEED
PASS|GRADED A+
How is skeletal muscle organized? - ANSWER Thick & thin filaments, sarcomeres,
myofibrils, skeletal muscle cells
What are the two types of contractile filaments? - ANSWER Thick & thin filaments
What are thick filaments made up of? - ANSWER Myosin
What are thin filaments made up of? - ANSWER Actin (primary component),
tropomyosin, troponin
How are thick filaments oriented? - ANSWER Each thick filaments consist of many
myosin molecules; half are oriented in one direction, half are oriented in the other direction
How are thin filaments oriented? - ANSWER Actin and tropomyosin arranges in a helix
configuration; troponin attached to actin/tropomyosin at regular intervals
What are sarcomeres? - ANSWER Functional contractile unit of skeletal muscle
What are Z disks? - ANSWER Protein disks at the ends of a sarcomere
How are sarcomeres organized? - ANSWER Thin filaments attach to Z disk, thick
filaments in center of sarcomere (connected to Z disk by titin)
What are myofibrils? - ANSWER Sarcomeres align end to end to form myofibrils
1
, What are T tubules? - ANSWER A T-tubule (or transverse tubule) is a deep invagination
of the sarcolemma, which is the plasma membrane of skeletal muscle and cardiac muscle
cells.
What is the function of T tubules? - ANSWER These invaginations allow depolarization
of the membrane to quickly penetrate to the interior of the cell.
What is a neuromuscular junction? - ANSWER A neuromuscular junction (or
myoneural junction) is a chemical synapse formed by the contact between a motor neuron
and a muscle fiber. It is at the neuromuscular junction that a motor neuron is able to
transmit a signal to the muscle fiber, causing muscle contraction.
What neurotransmitter is released at the neuromuscular junction? -
ANSWER Acetylcholine
What is the underlying mechanism that is common to all three types (skeletal, smooth, and
cardiac) of muscle that allows the cells to shorten? - ANSWER Cross-Bridge Cycle
What is meant by the term cross-bridge? - ANSWER Myosin heads of thick filaments
attach to thin filaments (form cross-bridges)
What is meant by the term power stroke? - ANSWER Myosin heads rotate, pulling thin
filaments along thick filaments toward center of the sarcomere
Describe the sequence of events that occur during the cross-bridge cycle in skeletal muscle
cells. - ANSWER 1. Binding of myosin to actin, inorganic phosphate released
2. Power stroke, actin gets pulled towards middle of sarcomere, ADP is released
3. Rigor (myosin in low-energy form), New ATP binds to myosin head
4. Unbinding of myosin and actin, ATP is hydrolyzed
5. Cocking of the myosin head (myosin in high-energy form)
2
UPDATE!!!!2025/2026|GUARANTEED
PASS|GRADED A+
How is skeletal muscle organized? - ANSWER Thick & thin filaments, sarcomeres,
myofibrils, skeletal muscle cells
What are the two types of contractile filaments? - ANSWER Thick & thin filaments
What are thick filaments made up of? - ANSWER Myosin
What are thin filaments made up of? - ANSWER Actin (primary component),
tropomyosin, troponin
How are thick filaments oriented? - ANSWER Each thick filaments consist of many
myosin molecules; half are oriented in one direction, half are oriented in the other direction
How are thin filaments oriented? - ANSWER Actin and tropomyosin arranges in a helix
configuration; troponin attached to actin/tropomyosin at regular intervals
What are sarcomeres? - ANSWER Functional contractile unit of skeletal muscle
What are Z disks? - ANSWER Protein disks at the ends of a sarcomere
How are sarcomeres organized? - ANSWER Thin filaments attach to Z disk, thick
filaments in center of sarcomere (connected to Z disk by titin)
What are myofibrils? - ANSWER Sarcomeres align end to end to form myofibrils
1
, What are T tubules? - ANSWER A T-tubule (or transverse tubule) is a deep invagination
of the sarcolemma, which is the plasma membrane of skeletal muscle and cardiac muscle
cells.
What is the function of T tubules? - ANSWER These invaginations allow depolarization
of the membrane to quickly penetrate to the interior of the cell.
What is a neuromuscular junction? - ANSWER A neuromuscular junction (or
myoneural junction) is a chemical synapse formed by the contact between a motor neuron
and a muscle fiber. It is at the neuromuscular junction that a motor neuron is able to
transmit a signal to the muscle fiber, causing muscle contraction.
What neurotransmitter is released at the neuromuscular junction? -
ANSWER Acetylcholine
What is the underlying mechanism that is common to all three types (skeletal, smooth, and
cardiac) of muscle that allows the cells to shorten? - ANSWER Cross-Bridge Cycle
What is meant by the term cross-bridge? - ANSWER Myosin heads of thick filaments
attach to thin filaments (form cross-bridges)
What is meant by the term power stroke? - ANSWER Myosin heads rotate, pulling thin
filaments along thick filaments toward center of the sarcomere
Describe the sequence of events that occur during the cross-bridge cycle in skeletal muscle
cells. - ANSWER 1. Binding of myosin to actin, inorganic phosphate released
2. Power stroke, actin gets pulled towards middle of sarcomere, ADP is released
3. Rigor (myosin in low-energy form), New ATP binds to myosin head
4. Unbinding of myosin and actin, ATP is hydrolyzed
5. Cocking of the myosin head (myosin in high-energy form)
2
