Muscle Properties
Which property allows a muscle to return to its original shape?
Elasticity
What ion is required for contraction to begin?
Calcium
Which muscle shape allows the greatest range of motion?
Fusiform
What is the muscle primarily responsible for movement called?
Agonist
Which lever class is most common in the body?
3rd class
Which property allows a muscle to respond to a stimulus?
Excitability
What is the role of ATP in muscle contraction?
Provides energy for contraction / detachment of myosin
Which muscle shape produces the most force?
Pennate
What is the role of an antagonist?
Opposes the agonist
Define a biarticular muscle
Crosses two joints
If extensibility is limited, what problem might occur?
Reduced range of motion
What happens if ATP is NOT available?
Muscle cannot relax (rigor state)
What connective tissue surrounds the entire muscle?
Epimysium
What does a synergist do?
Assists the agonist
Why does the body favor 3rd class levers?
Speed and range of motion over force
Which property is directly responsible for muscle shortening?
Contractility
What triggers the interaction between actin and myosin?
Calcium exposure
Which structure directly surrounds individual muscle fibers?
Endomysium
If the agonist is tight, what happens to the antagonist?
It becomes lengthened/weak
Give an example of a 2nd class lever in the body
Standing on toes
Which two properties work together to allow movement and return to normal?
Extensibility + Elasticity
Explain sliding filament theory (short version)
Actin and myosin slide past each other to shorten muscle
Why do pennate muscles produce more force?
More fibers packed into a smaller area
What is a fixator?
Stabilizes a joint or origin
Why are 1st class levers less common?
Less efficient for speed/force in the body