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