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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 |