Muscle Anatomy

What is the ability of a muscle to stretch called?

Extensibility

What is the ability of a muscle to shorten called?

Contractility

What term describes a muscle's response to stimuli?

Excitability

What is the ability of a muscle to return to its original shape after being stretched called?

Elasticity

What is the role of a synergist muscle?

It aids a prime mover in a movement.

What is a prime mover muscle?

The muscle with the major responsibility for a certain movement.

What is the function of an antagonist muscle?

It opposes or reverses a prime mover.

What does a fixator muscle do?

It stabilizes the origin of a prime mover.

What are specialized gap junctions found in cardiac cells called?

Intercalated discs.

What covering wraps the entire muscle?

Epilysium.

What covering wraps individual muscle fibers?

Endomysium.

What covering wraps a bundle of muscle fibers?

Perimysium.

Which type of muscle is multinucleated?

Skeletal muscle.

Which type of muscle is voluntary?

Skeletal muscle.

Which two types of muscles are striated?

Skeletal and cardiac muscle.

Which muscle type is found in hollow organs?

Smooth muscle.

Which muscle types have a single nucleus?

Cardiac and smooth muscle.

What is the order of skeletal muscles from largest to smallest?

Fascicle, muscle fiber, myofibril, sarcomere, myofilament.

What is the plasma membrane of skeletal muscle called?

Sarcolemma.

On which type of filament are myosin proteins found?

Thick filaments.

Why does skeletal muscle look striated?

Due to alternating A & I Bands.

What neurotransmitter does the brain send to stimulate a nerve in muscle contraction?

Acetylcholine.

What happens to the cell membrane when acetylcholine is present?

It depolarizes.

What does calcium binding allow during muscle contraction?

It allows myosin of the thick filaments to bind.

What must bind to myosin in order for it to release?

ATP.

What causes oxygen debt in muscles?

The buildup of lactic acid.

Which muscle fibers are associated with high endurance?

Slow twitch muscle fibers.

True or false: Muscle tone is when you have partially sustained muscle contraction.

TRUE.

What is sustained muscle contraction due to a lack of nutrients called?

A cramp.

What causes sustained muscle contraction in the absence of oxygen?

Lack of ATP.

What movement describes hands facing downward?

Pronate.

What does circumduction refer to?

Circular motion of the humerus on the scapula.

What is rotation in muscle movement?

A bone turning on its axis.

What does it mean to extend a joint?

To increase the angle of the joint.

What movement describes arms moving laterally away from the body?

Abduct.

What movement is described by hands facing upward?

Supinate.

What does flexion mean?

Decreasing the angle of a joint.

What does it mean to adduct?

To bring arms down to the sides.

What are the four muscles of the quadriceps?

Rectus Femoris, Vastus Lateralis, Vastus Intermedius, Vastus Medialis.

What are the three muscles of the hamstring?

Bicep Femoris, Semitendinosus, Semimembranosus.

What is the action of the deltoid muscle?

Abduction.

What is the action of the bicep femoris?

Flexion.

What shape is the trapezius muscle?

Table.

What shape is the deltoid muscle?

Triangle.

What shape does the Rectus Femoris muscle have?

Straight & long.

What shape is the orbicularis oculi muscle?

Circular.