Muscle Structure
Connective tissue that surrounds a single muscle fiber.
What is endomysium?
Thin protein filaments that interact with myosin to create movement.
What is actin?
Ion needed for muscle contraction; binds to troponin.
What is calcium (Ca²⁺)?
Muscle type that is voluntary and striated.
What is skeletal muscle?
The neurotransmitter released at the neuromuscular junction to start muscle contraction.
What is acetylcholine (ACh)?
Connective tissue that surrounds a fascicle (bundle of muscle fibers).
What is perimysium?
Thick protein filaments responsible for pulling actin during contraction.
What is myosin?
Molecule required to detach myosin heads after a power stroke.
What is ATP?
Muscle type found only in the heart; involuntary with intercalated discs.
What is cardiac muscle?
Structure in the muscle cell that stores and releases calcium.
What is the sarcoplasmic reticulum?
Connective tissue that surrounds the entire muscle.
What is epimysium?
Middle region of sarcomere that contains only thick filaments.
What is the H-zone?
Protein that blocks actin binding sites at rest.
What is tropomyosin?
Muscle type found in hollow organs; involuntary and non-striated.
What is smooth muscle?
The electrical signal that travels down the sarcolemma and triggers Ca²⁺ release.
What is an action potential?
The plasma membrane of a muscle cell.
What is the sarcolemma?
Dark band where thick filaments are located (and may overlap thin filaments).
What is the A-band?
Protein that binds calcium to move tropomyosin.
What is troponin?
Structures connecting cardiac muscle cells to allow synchronized contractions.
What are intercalated discs?
When myosin pulls actin inward, shortening the sarcomere.
What is the power stroke?
The repeating functional unit of muscle responsible for contraction.
What is the sarcomere?
Line in the center of the sarcomere where thick filaments anchor.
What is the M-line?
Explanation for how myosin pulls actin to shorten the sarcomere.
What is the sliding filament theory?
What gives skeletal muscle its striations.
What is the arrangement of sarcomeres?
The process where actin filaments slide past myosin, shortening the muscle fiber.
What is muscle contraction?
(Alternative accepted: What is the sliding filament mechanism?)