What are the three types of muscles

skeletal, cardiac, smooth

Skeletal muscles

multinucleated, striated, voluntary muscles (body structure)

Cardiac Muscles

single-nucleated, striated, involuntary muscles (heart muscles)

Smooth Muscles

unstriated, involuntary muscles (lining of organs)

Extrinsic muscles

muscles with one or more attachments to the trunk or limbs

Intrinsic muscles

The muscle attaches to only bone of the limb

ex: muscles of the forearm

Components of muscles

myofibrils and myofilaments

Myofibrils

Make up muscle fibers

Myofilaments

Microscopic bundles of proteins contained in myofibrils

Myofilaments contain what filaments

myosin and actin

Myosin

Thick filaments

Actin

Thin filaments

Muscle associated connective tissues

Endomysium, perimysium, epimysium

Endomysium

Layer of connective tissue surrounding individual muscle fibers

What does endomysium contain

Capillaries, nerve fibers, and satellite cells

Perimysium

Layer of connective tissue that surrounds a group of muscle fibers

What does perimysium contain

Blood vessels and nerves

Epimysium

Dense, connective tissue sheet that covers a whole muscle

Epimusium does what

Delineates muscles from each other and other tissues

Muscle Arrangements

Parallel muscles and pennate muscles (unipennate, bipennate, multipennate)

Parallel Muscles

Strap-like muscles in which fibers run parallel to each other

Pennate muscles

Muscles with tendons throughout their length

Unipennate muscles

Tendons run along one side

Bipennate Muscles

Tendon runs along both sides

• converges on a tendon from both directions

Multipennate

Tendon distributed throughout the muscle

Muscle Attachments

Fleshy, Tendinous, aponeurotic

Fleshy attachments

Looks like muscle attaches directly to the bone

• actually connects by really small fibers

Tendinous attachments

Involves cord-like connective tissues

• attaches pennate to bone

Aponeurotic attachments

flat, tendinous sheet attaches the muscle

Origin

More fixed point of a muscular attachment

• typically more proximal attachment

Insertion

More movable point of muscular attachment

• Typically more distal attachment

Types of Muscle Function

Flexor, extensor, agonist, antagonist, fixator, synergist

Flexor

Muscle that closes a joint or results in angulation of a bone

Extensor

Muscle that opens a joint or results in straightening of a bone

Agonist

(Prime Mover) Muscle involved in characteristic movement of a joint

Antagonist

Muscle that has an action directly opposite agonist muscles

Fixator

Muscle that stabilizes joints when agonists are in action

Synergist

Works against nay undesired actions of agonist muscles

• helps agonist work more efficiently