Muscles Are Built to Move
LEARNING OBJECTiVES
1.
Describe
the structure of skeletal muscle
tissue.
2.
explain
how skeletal muscle tissue shortens.
3.
Outline
the sequence of events of skeletal mus-
cle contraction (excitation-contraction coupling).
4.
associate
the type of muscle fiber (cell) with
the source of energy in given situations.
InSight
T h e s t r u c tu r e o f a s k e le ta l m u s c le a n d its c o n n e c t iv e t is s u e
c o v e r in g s : A m a c r o s c o p i c v ie w
Figure 6.2
The cylindrical muscle fibers (cells) contain myofibrils, consisting
of overlapping thin filaments and thick filaments that are arranged
into sarcomeres. This arrangement of overlapping filaments allows
the muscle to shorten, thereby generating force and movements.
Fascicle—
156
Periosteum
Tendon
Epimysium
Skeletal
muscle
Perimysium
Epimysium
Fascicle
Perimysium
Muscle
fiber (cell)
Myofibril
a.
Muscles
are
bundles of longitudinal
muscle fibers (cells) surrounded by
connective tissue.
Each
fiber has
an
artery, 1-2
veins, and
a
motor nerve cell.
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