Muscle Fibers Flashcards
What is each myofibril made up up?
Contractile sarcomeres
What is a muscle fiber equivalent to?
Muscle cell
What muscle fiber contains a specialized endoplasmic reticulum?
Skeletal muscle fibers
What is the cell membrane surrounding the skeletal muscle called?
Sarcolemma
What are myofibrils?
multiple bundles of contractile proteins
How are sarcomeres positioned along a myofibril?
Strung out in a single file line
What is a single contractile unit?
Sarcomere
What is the endoplasmic reticulum called in muscles?
Sarcoplasmic reticulum
What does the sarcoplasmic reticulum store?
Calcium-needed for muscle contraction
What surrounds each myofibril?
Sarcoplasmic reticulum
What is the function of the sarcoplasmic reticulum?
allowing it to convey a signal to all parts of the muscle to contract or relax.
What is actin?
A thin myofilament
What is myosin?
A thick myofilament with small protruding heads which bind to regions on the thin filament
What are z lines?
A dense protein disc that flanks each individual sarcomere to hold the myofilaments in place
What is the sliding filament theory?
put forward following the discovery that the A band (myosin) is the same length in contracted and relaxed muscles
