Sliding Filament animation

Skeletal muscle fibers (the cells) have ____ nucleus/nuclei

• one

• many

The contractile unit of a myofibril is called a

• sarcomere

• fascicle

• nucleus

• stringypull

The thin filament is made of ___and is anchored to the z-line/sarcomere border

• actin

• myosin

When contraction is happening, the myosin ____ the actin

• pulls

• pushes

• dissolves

• becomes

ATP allows the myosin to ____ the actin

• release

• merge into

• dissolve

• eat

Stores the calcium

• nucleus

• sarcoplasmic reticulum

• myosin

• sarcolemma

When a muscle contracts, the z-lines of a sarcomere get

• closer together

• farther apart

• stinky

• converted to gas