BMS 300 MUSCULAR SYSTEM EXAM
types of skeletal muscles
smooth muscle, striated muscle ( skeletal)
structural organization of skeletal muscles
muscle is connected to bone by tendons and made up of bundles/fascicles which
are made up of myofibers ( muscle cells )
what causes the multinucleated and striated appearance of muscle fibers
- develop through the fusion of embryonic cells called myoblasts, a muscle fibre
forms by the fusion of myoblasts
sarcolemma
the outer membrane of a muscle
dihydropyridine receptors
sensitive to changes in voltage
ryanodine receptor
calcium-release channel found in the lateral sacs of the sarcoplasmic reticulum
in skeletal muscle cells
sarcoplasmic reticulum
Modified ER in skeletal muscle cells
how to muscles produce force
sarcomeres slide over each other to provide force and contract, interactions of
thick and thin filament
Dark bands in a sarcomere
A-Band= myosin
Light bands in a sarcomere
I-Band= Actin
, thick filaments
myosin, arranged in a bundle with the tails of myosin molecules forming central
region of thick filament and heads extending outward , responsible for binding
to to the thin filaments and generating force for muscle contraction
thin filaments
composed of actin, tropomyosin and troponin
actin
forms a helical structure and is a primary protein that makes up thin filaments ,
has myosin binding sites are where myosin heads attach during muscle
contraction
tropomyosin
long thread like protein that runs along the groove of the actin helix , in resting
muscle it blocks myosin binding sites preventing it from binding
troponin
complex of 3 proteins associated with tropomyosin , it has binding sites for ca
ions when they bind to this it causes a conformational change exposing the
binding sites
muscle contraction process ( sliding filament theory)
1. resting state
2. initiation of contraction
3. cross - bridge formation
4. power stroke
5. muscle contraction
resting phase
in a resting muscle the myosin binding sites on actin are covered by
tropomyosin , preventing myosin from binding to actin
initiation of contraction
types of skeletal muscles
smooth muscle, striated muscle ( skeletal)
structural organization of skeletal muscles
muscle is connected to bone by tendons and made up of bundles/fascicles which
are made up of myofibers ( muscle cells )
what causes the multinucleated and striated appearance of muscle fibers
- develop through the fusion of embryonic cells called myoblasts, a muscle fibre
forms by the fusion of myoblasts
sarcolemma
the outer membrane of a muscle
dihydropyridine receptors
sensitive to changes in voltage
ryanodine receptor
calcium-release channel found in the lateral sacs of the sarcoplasmic reticulum
in skeletal muscle cells
sarcoplasmic reticulum
Modified ER in skeletal muscle cells
how to muscles produce force
sarcomeres slide over each other to provide force and contract, interactions of
thick and thin filament
Dark bands in a sarcomere
A-Band= myosin
Light bands in a sarcomere
I-Band= Actin
, thick filaments
myosin, arranged in a bundle with the tails of myosin molecules forming central
region of thick filament and heads extending outward , responsible for binding
to to the thin filaments and generating force for muscle contraction
thin filaments
composed of actin, tropomyosin and troponin
actin
forms a helical structure and is a primary protein that makes up thin filaments ,
has myosin binding sites are where myosin heads attach during muscle
contraction
tropomyosin
long thread like protein that runs along the groove of the actin helix , in resting
muscle it blocks myosin binding sites preventing it from binding
troponin
complex of 3 proteins associated with tropomyosin , it has binding sites for ca
ions when they bind to this it causes a conformational change exposing the
binding sites
muscle contraction process ( sliding filament theory)
1. resting state
2. initiation of contraction
3. cross - bridge formation
4. power stroke
5. muscle contraction
resting phase
in a resting muscle the myosin binding sites on actin are covered by
tropomyosin , preventing myosin from binding to actin
initiation of contraction
