Muscles

The word “striated” means striped The word “striated” means striped. Skeletal muscle appears striped under a microscope.

Skeletal Muscle

Skeletal Muscle Structure

Skeletal Muscle Structure

This model of the muscles uses straws to represent fibers. Green = endomysium Yellow = perimysium Blue = epimysium

Cardiac Muscle

Cardiac Muscle  Intercalated discs

Cardiac Muscle

Smooth Muscle (2 varieties)

Smooth Muscle (2 varieties)

Myofilaments (2 types)

SLIDING FILAMENT THEORY (MODEL)

Actin myosin https://www.youtube.com/watch?v=CepeYFvqmk4 https://www.youtube.com/watch?v=YAJ-9nPSqwA

Sliding Filament Handout

Sliding Filament Handout

Cardiac Muscle (Ca) Over half of the calcium which the cardiac cell uses for contraction originates from outside of the muscle cell.   During relaxation much of the calcium will be pumped out of the cell (rather than back into the endoplasmic reticulum.) Calcium and sodium ions slowly leak through the membrane When enough of these ions enter, contraction will occur.  The faster the ions leak into the cell, the faster the cell will contract