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ch6 muscles
Question | Answer |
---|---|
ability of skeletal muscle to shorten with force | contractility |
the capacity of skeletal muscle to respond to a stimulus | excitability |
ability to be stretched | extensibility |
ability to recoil to original length | elasticity |
connective tissue sheath surrounding skeletal muscle | epimysium |
connective tissue located outside the epimysium | fascia |
loose connective tissue surrounding fascicle | perimysim |
fascicle composed of singe muscle cells called | fibers |
each fiber surrounded by connective tissue sheath | endomysium |
cytoplasm in each fiber is filled with | myofibrils |
myofibrils consist of 2 major protein fibers | actin, myosin |
thin myofibrils | actin |
thick myofibrils | myosin |
actin and myosin myofibraments form highly ordered units | sarcomeres |
the basic structure and functional unity of the muscle | sarcomere |
each sarcomere extends from | one z line to another z line |
the arrangement of these two give a banded appearance | actin, myosin |
on each side of the z line there is a light area | I band |
I band consists of | actin |
darker central region in each sarcomere | A band |
A band consists of | myosin |
center of each sarcomere a light area called | H band |
H band consists of | myosin |
dark staining band | M line |
the charge difference across the membrane | resting membrane potential |
brief reversal back of the charge | action potential |
nerve cells that carry action potentials to skeletal muscle fibers | motor neurons |
axons enter the muscles and | branch |
each branch that connects to the muscle forms a | neuromuscular junction |
neuromuscular junction or | synapse |
a single motor neuron and all the skeletal muscle fibers it innervates | motor unit |
many motor units form a | single muscle |
the enlarged nerve terminal | presynaptic terminal |
each presynaptic terminal contains | synaptic vesicles |
secretes a neurotransmitter | synaptic vesicles |
neurotransmitter | acetylcholine |
diffuses across the synaptic cleft and binds the postsynaptic terminal | acetylcholine |
when the sarcomeres shorten it causes the muscle to | shorten |
sliding of actin myofilaments past myosin myofilaments during contraction | sliding filament mechanism |
contraction of an entire muscle in response to a stimulus that causes the action potential in one or more muscle fibers | muscle twitch |
a muscle fiber will not respond to a stimulus until that stimulus reaches a level called | threshold |
threshold where muscle fibers will contract maximally | all-or-none response |
the time between application of a stimulus to a motor neuron and the beginning of a contraction | lag phase |
time of contraction | contraction phase |
the time which the muscle relaxes | relaxation phase |
muscle remains contracted without relaxing | tetany |
increase in number of motor units being activated | recruitment |
needed for muscle contraction | ATP |
produced in mitochondria | ATP |
short lived and unstable | ATP |
ATP degenerates to the more stable | ADP |
raises the eyebrows | occipital frontals |
closes the eyelids | orbicularis oculi |
puckers the lips | orbicularis oris |
flattens cheeks | buccinator |
smiling muscle | zygomaticus |
sneering | levator labii superioris |
frowning | depressor anguli oris |
chewing | mastication |
change shape of tongue | intrinsic |
move tongue | extrensic |
lateral neck muscle and prime mover | sternocleidomastoid |
group of muscles on each side of the back | erector spinae |
most involved in breathing | external and internal intercostals |
rotates scapula | trapezius |
pulls scapula anteriorly | serratus anterior |
the arm is attached to the thorax by | pectoralis major and latissimus dorsal muscles |
flexes arm | pectoralis major |
rotated the arm | latissimus dorsi |
attached the humerus to the scapula | deltoid |
extends forearm | triceps branchii |
flexes forearm | biceps branchii |
flexes and supinates the forearm | branchioradialis |
flexes the wrist | flexor carpi |
extends the wrist | extensor carpi |
flexes the fingers | flexor digitorium |
extends the fingers | extensor digitorium |