This cross-section of skeletal muscle shows the connective tissue sheaths that organize muscle fibers into muscles. These sheaths usually conduct forces generated by muscle contraction through tendons to bone.
Endomysium - thin layer of connective tissue that surrounds each muscle cell.
Capillaries travel through this layer and provide a rich blood supply. The capillaries are found at the corners of the muscle cells.
Small nerve fibers are also found in this layer
Perimysium - thick layer of connective tissue that surrounds a group of muscle cells to form fascicles.
Blood vessels travel through this layer
Nerves are found in this layer
Epimysium - dense connective tissue that surrounds the entire muscle and is usually continuous with a tendon.
Skeletal muscle cells (or fibers) are classified based on contractile speed and metabolic activity. Two types of fibers can be distinguished in this specimen.
Type I - smaller muscle cells that specialize in long, slow contractions. They stain darker than type II fibers.
Type II - larger muscle cells that specialize in fast contractions. The majority of muscle cells in this specimen.
The cross section of a muscle spindle is present in this section. Muscle spindles are sensory receptors within a muscle that primarily detect changes in length of a muscle.