Muscle Contractions

Skeletal muscles always work _____.

• in groups

• in pairs

• singly

• none of the above

Smooth muscle and cardiac muscle are considered _____ muscles because we can’t control them consciously.

• Immovable

• Involuntary

• Skeletal

• none of the above

What is labeled "4" (the blue/purple part) in the diagram?

• sarcolemma

• sarcoplasmic reticulum

• transverse tubules

• myofibril

What is the length between Z-lines of an actin molecule called?

• fascicle

• sarcomere

• myosin binding site

• sarcoplasmic length

Found in the heart

• smooth

• cardiac

• skeletal

• all

Why is calcium needed for muscle contraction?

• causes the binding of neurotransmitters to receptors

• causes the binding of myosin to actin

• increases the action potential

• changes the shape of myosin

What structure is shown here?

• neuromuscular junction

• sarcomere

• origin and insertion

• synaptic cleft

A bundle of muscle fibers is known as a...

• fascicle

• sarcomere

• tendon

• epimysium

Another name for a muscle cell is...

• muscle fiber

• fascicle

• sarcomere

• thick filament

The basic functional unit of a muscle fiber separated by the Z lines is called _____.

• sarcolemma

• sarcomere

• filaments

• myofibril