Skeletal Muscle Structure Flashcards
Types of muscle
smooth
cardiac
skeletal
Smooth muscle
Smooth involuntary: not striated, single nuclei, digestive, respiratory, and vascular tissues, extremely elastic and pliable
Cardiac Muscle
Striated involuntary: cardiac muscle, branched structure, intercalated discs, 1-2 nuclei/cell
Skeletal Muscle
voluntary striated: skeletal muscle, multi-nucleated, most abundant form
Muscle tasks
primer movers
antagonists
fixation
syngerists
muscles have specific tasks
Prime movers
accomplish specific movement
must relax for prime mover to perform
fixation movers
hold the base for prime movers
synergists
stabilize in opposition to gravity
(keeps us standing)
Connective tissue
collagen
elastin
reticular fibers
Collagen
most abundant protein
water soluble
inelastic
Elastin
very elastic
not water soluble
blood vessels, tendons, and ligaments
reticular fibers
small and delicate
surround many organs
epimysium
silver skin
around muscle body
anchors to tendon
protection
perimysium
around muscle bundles
pathway for nerves and blood flow
marbling
endomysium
around muscle fibers
tenderness
Arrangement of muscle fibers
origins to insertion
angular
fulsiform
pinnate (uni, bi, multi)
Origins to insertion
small muscles (intercostae)
Angular
Angular to longitudinal section of the muscle (longissimus dorsi)
Fulsiform
fibers run parallel to the muscle (biceps brachi)
pinnate
originate from connective sheaths in leaf array (deltoid)
levels of muscle structure
muscle
muscle bundle
muscle fiber (myofiber)
myofribrils
myofilaments
Muscle bundles
contains 10-20 myofibers
encased by perimysium
can see with the naked eye
myofiber
individual muscle cell
multinucleated
encased by endomysium
cell wall: sarcolemma
Myofibrils
embedded in sarcoplasm
mitochondria located between myofibrils
compromised of repeating units
sarcomeres
A band
I band
Z disk
H zone
Pseudo H zone
