MUSCLES Flashcards
FUNCTION OF MUSCLES
producing movement
maintaining posture
stabilizing joints
generating heat
Many oval nuclei can be seen just beneath
the plasma membrane,
sarcolemma
The nuclei are pushed aside by long
ribbonlike organelles,
myofibrils
Alternating dark and light bands
along the length of the perfectly aligned myofibrils give
the muscle cell as a whole its striped appearance.
light and dark bands
The myofibrils are actually chains of tiny
contractile units called sarcomeres, which are aligned
end to end like boxcars in a train along the length of the
myofibrils.
sarcomeres
There are two types of threadlike protein
myofilaments within each of our “boxcar” sarcomeres.
myofilaments
The larger, thick filaments, also
called myosin filaments,
thick filaments
Notice that the midparts of the thick
filaments are smooth, but their ends are studded with
thick projections; these projections, or myosin beads,
are called cross bridges when they link the thick and thin
filaments together during contraction.
cross bridges
The thin filaments are composed of the
contractile protein called actin,
thin filaments
a
specialized smooth endoplasmic reticulum; the
interconnecting tubules and sacs of the SR surround
each and every myofibril just as the sleeve of a loosely
crocheted sweater surrounds your arm, and its major role
is to store calcium and to release it on demand.
sarcoplasmic reticulum
types of body movements
origin
insertion
flexion
extension
rotation
abduction
adduction
circumduction
Interactions of Skeletal Muscles in the Body
prime mover
antagonists
synergists
fixators
special movements
dorsiflexion
plantarflexion
inversion and eversion
supination and pronation
arrangement of muscles
circular
convergent
parallel
pennate
