06.3B2 U6P1 (PART B) Organizational Levels of Skeletal Muscle (Advanced)

Skeletal Muscle (Description)

An organ made up of many muscle fibers that are bundled into structures called fascicles.

Skeletal Muscle (Image)

Fascicle (Description)

A bundle of muscle fibers

Fascicle (Image)

Muscle Fiber (Description)

A long cylindrical multinucleate cell; nuclei are just beneath the sarcolemma; sarcolemma is a specialized plasma membrane; many mitochondria provide energy for muscle contraction; contain sarcoplasmic reticulum, T tubules, and myofibrils

Muscle Fiber (Image)

Sarcomere (Description)

The functional unit of muscle that produces muscular contraction and consists of repeating sections of actin and myosin.

Sarcomere (Image)

Myofibril (Description)

The contractile organelles of a skeletal muscle fiber that contain actin and myosin

Myofibril (Image)

Myofilaments (Description)

The contractile proteins, actin and myosin, of muscle cells

Myofilaments (Image)