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)