striated in appearance but not so markedly

the heart 

thin filament composed of globular protein linked together to form a double filamnet

1. tropomyosin-filament that lies in the groove and covers part of the actin filament

2.  troponin-protein attached to tropomyosin

3.  myosin-thick filament head and neck attached to tail...heads facing inward

bundles of filaments arranged so that all of the actin and myosin filaments line up forming alternating bands

1.  I band-isotropic band

2. A-Band antisotropic band

3. titan bands

1.Sarcolemma-membrane around the structure

2.Nuclei-may have hundreds

3.Mitochondria-generate ATP using oxygen

4.sarcoplasmic reticulum-longitudinal tubular system with cross connections

5.T-tubules-extend transversly across the fiber continuous with sarcolemma

-myofilaments

-myofibrils

-muscle fibers

-fascicle

-whole muscle 

endomysium-mostly reticular fibers, covers skeletal muscle channels blood capillaries

perimysium-collagen and elastic fibers that surround each fassicle, channel for large blood vessels and nerves

epimysium-dense irregular CT, surrounding whole muscle, connected to deep fascia

-neurotransmitter molecules released fom presynaptic neuron

-diffuse to end plate

-bind and activate molecular receptors

-activated receptors initiate an electrical event spreads over sarcolemma and down the t tubules

-releases Ca

-Ca binds to troponin

-tropomyosin moves allowing myosin heads to bind to actin and pull inward

-Ca falls and everything goes back to normal

have ability to contract quickly

fatigue quickly

contract slowly

can stay contracted for a long period of time