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excitability

the ability to receive and respond to a stimulus, that is, any change in the environment inside or outside the body.

contractility

the ability to shorten forcibly when adequately stimulated

extensibility

the ability to be stretched or extended

elasticity

the ability of a muscle cell to recoil and resume its resting length after being stretched

epimysium

an "overcoat" of dense irregular connective tissue that surrounds the whole muscle. It means "outside the muscle"

perimysium

surrounds each fascicle "around the muscle"

fascicle

muscle fibers are grouped resembles a bundle of sticks within each skeletal muscle

endomysium

"within the muscle" whispy sheath of connective tissue that surrounds each individual muscle fiber.

insertion

moveable bone

origin

immovable bone

direct attachment

epimysium of the muscle is fused to the periosteum of a bone or perichondrium of a cartilage

indirect attachment

muscles connective tisue wrappings extend beyond the muscle either as a ropelike tendon of a sheetlike aponeurosis
much more common because of durability and small size

sarcolemma

the plasma membrane of a muscle fiber, usually under the endomysium. below this is mutiple oval nuclei

sarcoplasm

the cytoplasm of a muscle cell contains large amounts of glycosomes

glycosomes

granules of stored glycogen that provide glucose during periods of muscle cell activity

myoglobin

a red pigment that stores oxygen

myofibril

rodlike contractile elements that occupy most of the muscle cell volume. they appear banded and have sarcomeres end to end. bundles of myofilament

sarcomere

the smallest contractile unit composed of myofilaments made of contractile proteins, region between the z disks made up of the a band and two half I bands at each end.

Thin filament

contain actin molecule

Thick filament

contain bundled myosin molecules

striations

a repeating series of dark and light bands are evident along the length of each myofibril

cross bridges

this forms when linking of the thin and thick filaments together occurs

actin

is a protein in which has a kidney shape and is used to bear the active sites in which myosin heads attach during contraction, polypeptide subunits they are in thin filament

tropomyosin

rod shaped protein that wraps around the thin filament to help stiffen and stabilize it (actin core)

troponin

globular three polpeptide complex one binds to tropomyosin another binds to actin and the last one binds calcium ions

titin

helps the muscle to spring back into shape after being stretched extends from the z disk to the thick filament and forms the core of the thick filament

muscle tone

relaxed muscles that are slightly contracted to keep the muscles firm and healthy and ready to respond to stimulation. helps maintain posture and stabilize joints

Aerobic endurance

length of time a muscle can continue to contract using aerobic pathways

anaerobic threshold

the point in time when muscle metabolism converts to anaerobic glycolysis

prime mover

muscle that has a major responsibility for producing a specific function

antagonist

muscles that oppose or revers a particular movement

synergist

help prime movers by adding a little extra force and reducing undesireable movements

fixators

synergists immobilize a boe or a muscles origin so that the prime mover has a stable base on which to act

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