microscopic anatomy

what do muscle cells look like?

• long & cylindrical

• multi-nucleate

• striations

muscle fibers

muscle cells

fascicle

bundle of muscle fibers

endomysium

delicate connective tissue surrounding each muscle fiber

perimysium

connective tissue encasing each fascicle

epimysium

“overcoat” of connective tissue, covers the entire muscle

• many fascicle bound together

sarcolema

cell membrane of a muscle cell

• contains a sugar for anchoring

myofibrils

contains ribbon-like organelles, gives striped appearance (dark & light)

• allows for contractions

sarcomeres

tiny chains of contractile myofibrils arranged end to end

myofilaments

thread-like protein strands within sarcomeres

• thick & thin

think filaments

• made of myosin (protein)

• contain enzyme to split ATP to generate power for muscle contractions

thin filaments

made of actin (protein)