THE MUSCULAR SYSTEM
MUSCLE FUNCTION
Function varied by type of muscle
Basic functions:
Provides locomotion by contracting to change the positions
of bones and maintains joint angles against the pull of
___________
Distribution of blood
Heat production (shivering)
THREE TYPES
1.
2. .
3.
FUNCTIONS OF SKELETAL MUSCLES
______________ ___________– tendons may extend across joints
Maintains posture, which also takes strain off bones and joints
Opposes the force of gravity and keeps us upright
Muscle contraction refinements allow us to assume different positions
_____________
Contraction produces _________
SKELETAL MUSCLE
___________________
Striated
______________
Cylindrical fibers run the length of the muscle
Can contract multiple times between relaxations, can fatigue (use up all the available ATP)
CONNECTIVE TISSUE COVERING
________________
Outer covering of muscle (covers bundles of fasicles), extends beyond muscle to
become tendon
_________________
Surrounds bundles of muscle fibers called fasicles
_________________
Covers individual fibers (cells)
SKELETAL MUSCLE
Voluntary striated muscle fiber
Long multinucleated cell with visible striations
“______________” Muscle fibers - are joined in strands that are grouped in bundles
TWO TYPES
Type I – “_______ - _________”
Slower contracting but capable for long periods of time
Type II – “_______ - _________”
Faster contracting but more susceptible to fatigue
ACTIONS OF SKELETAL MUSCLE
_________________ - oppose or resist the action of another muscle (such as is the case of the
biceps and the triceps)
________________ - work together to produce a common effect (such as in the action of making
a fist, in which the muscles of the forearm and fingers work together)
SMOOTH MUSCLE
_________________
Non-striated
______________
Spindle shaped cells, usually found in parallel lines forming “sheets”
Found in walls of hollow organs (also called ____________)
Slow contractions but can sustain – doesn’t _____________ easily
FUNCTIONS OF SMOOTH MUSCLE
Smooth muscle is found in the walls of _________ __________ like your intestines and stomach
They work ___________________ without you being aware of them
The muscular walls of your intestines contract to push food through your body
CONTRACTIONS OF SMOOTH MUSCLE
Contraction cause fibers to _____________ in all directions, cells go from spindle shaped to
more _________
Contraction of smooth muscle is much __________ than skeletal muscle but smooth muscle is
more fatigue resistant than skeletal muscle and can maintain contractions for far longer
WHERE TO FIND SMOOTH MUSCLE
Blood Vessel Walls
CARDIAC MUSCLE
________________
Striated
________________
Auto-rhythmic – doesn’t require nervous system stimulation to contract
Cylindrical and branched cells (fibers)
Joined by intercalated _________ – allow passage of electrical activity throughout muscle
Relax completely between contractions, avoids fatigue
FUNCTION OF CARDIAC MUSCLE
The cardiac muscle has only one job; its job is to _______________________________________________
______________________________________________________________________________________________________
If the cardiac muscle stops, you stop
3 MAIN MUSCLE GROUPS
__________ muscles - trunk and tail muscles of fishes and tetrapods
____________________ muscles - also called visceral muscles, such as those associated with the
gills, jaws and hyoid apparatus
_________________ muscles - fin muscles of fishes and limb muscles of tetrapods
ACTIONS OF MUSCLES
____________ - decreases the angle at a joint
Extensor - increases the angle at a joint
_____________ - moves a bone away from the midline
Adductor - moves a bone closer to the midline
____________ - produces an upward movement
Depressor - produces a downward movement
Supinator - turns the palm upward or anteriorly
___________- turns the palm downward
Sphincter - decreases the size of an opening
___________ - makes a body part more rigid
____________ - moves a bone around its longitudinal axis
SIZE OF MUSCLES
Maximus = ______________
Minimus = ______________
Longus = ____________
Brevis = ______________
TENDONS
A ___________ is a fibrous connective tissue which attaches __________ to _________
Tendons may also attach muscles to ______________ such as the eyeball
_____________ Tendon: allow things such as the hoof to move forward (not very strong)
___________ Tendon: allows structures such as the hoof to bend and propel the animal forward
(strong)