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muscles
mrs. eastham anat./phys.
| question | Answer |
|---|---|
| contractility | ability of skeletal muscles to shorten with force |
| contractility | ability of skeletal muscles to shorten with force |
| excitability | capacity of skeletal muscles to respond to a stimulus |
| excitability | capacity of skeletal muscles to respond to a stimulus |
| extensibility | ability to be stretched |
| extensibility | ability to be stretched |
| elasticity | ability to recoil to their original resting length after they have been stretched |
| elasticity | ability to recoil to their original resting length after they have been stretched |
| epimysium | skeletal muscle surrounded by a connective tissue sheath |
| epimysium | skeletal muscle surrounded by a connective tissue sheath |
| fascia | another connective tissue located outside the epimysium |
| a muscle is composed of numerous visible bundles called | fasciculi |
| fasciculi are surrounded by loose connective tissue called | perimysium |
| muscle fibers | muscle cells |
| muscle fibers | muscle cells |
| each muscle fiber is a single cylindrical cell connecting several | nuclei |
| endomysium | a connective tissue sheath that surrounds fibers |
| myofibrils | a threadlike structure that extends from one end of the fiber to the other. |
| myofibrils | a threadlike structure that extends from one end of the fiber to the other. |
| actin myofilaments | thin myofilaments |
| actin myofilaments | thin myofilaments |
| myosin myofilaments | thick myofilaments |
| myosin myofilaments | thick myofilaments |
| actin myofilaments resemble | 2 minute strands of pearls twisted together |
| actin myofilaments resemble | 2 minute strands of pearls twisted together |
| myosin myofilaments resemble | bundles of minute golf clubs |
| myosin myofilaments resemble | bundles of minute golf clubs |
| sarcomeres | ordered units joined end to end to form the myofibril |
| basic structural and functional unit of the muscle | sarcomere |
| each sarcomere extends from what to what | z line to z line |
| each sarcomere extends from what to what | z line to z line |
| on each side of the z line is a light area called a ____, that consists to actin | I band |
| on each side of the z line is a light area called a ____, that consists to actin | I band |
| in the center of each sarcomere is another light are called the ____, which consists of only myosin | H zone |
| what is the A band | darker central region of each sarcomere |
| dark staining band in the center of the sarcomere | M line |
| in the center of each sarcomere is another light are called the ____, which consists of only myosin | H zone |
| the outside of most cell membranes are | positively charged |
| dark staining band in the center of the sarcomere | M line |
| the inside of most cell membranes are | negatively charged |
| resting membrane potential | charge difference across the membrane |
| action potential | brief reversal back of a charge |
| the outside of most cell membranes are | positively charged |
| motor neurons | nerve cells that carry action potentials to skeletal muscle fibers |
| axons enter the muscles and branch. each branch that connects to the muscle forms a _______, or ____ near the center of the cell. | neuromuscular junction; synapse |
| the inside of most cell membranes are | negatively charged |
| motor unit | a single motor neuron and all the skeletal muscle fibers it innervates |
| action potential | brief reversal back of a charge |
| motor neurons | nerve cells that carry action potentials to skeletal muscle fibers |
| axons enter the muscles and branch. each branch that connects to the muscle forms a _______, or ____ near the center of the cell. | neuromuscular junction; synapse |
| motor unit | a single motor neuron and all the skeletal muscle fibers it innervates |
| presynaptic terminal | enlarged nerve terminal |
| synaptic cleft | the space between the presynaptic terminal and the muscle cell |
| postsynaptic terminal | muscle fiber |
| each presynaptic terminal contains | synaptic vesicles |
| synaptic vesicles secrete a neurotransmitter called | acetycholine |
| muscle contraction | occurs as actin and myosin myofilaments slide past one another causing the sarcomeres to shorten |
| sliding filament mechanism | the sliding of actin myofilaments past myosin myofilaments during contraction |
| between the H, the I ,and the A band, which one does not shorten in length? | the A band |
| muscle twitch | a contraction of an entire muscle in response to a stimulus |
| a muscle fiber will not respond to stimulus until the stimulus reaches a level called | threshold |
| all-or-more response | the phenomenon of the threshold |
| lag phase | the time between application of a stimulus to a motor neuron and the beginning of a contraction |
| contraction phase | the time of contraction |
| relaxation phase | the time during which the muscle relaxes |
| tetany | where the muscle remains contracted without relaxing |
| recuitment | the increase in number of motor units being activated |
| ATP | needed for energy for muscle contraction |
| ATP produces | mitochondria |
| adenosine triphosphate | ATP |
| adenosine diphosphate | ADP |
| creatine phosphate | high-energy molecule |
| anaerobic respiration | without oxygen |
| aerobic respiration | with oxygen |
| oxygen debt | amount of oxygen needed in chemical reactions to convert lactic acid to glucose and to replenish the depleted stores of creatine phosphate stores in muscle cells. |
| muscle fatigue | when ATP is used during muscle contraction faster than it can be produced in the muscle cells |
| isometric | equal distance |
| isotonic | equal tension |
| muscle tone | constant tension produced by muscles of the body for long periods of time |
| fast-twitch fibers | contract quickly and fatigue quickly |
| slow-twitch fibers | contract more slowly and are more resistant to fatigue |
| origin | head |
| insertion | the end of the muscle undergoing the greatest movement |
| synergists | muscles that work together to accomplish specific movements |
| antagonists | muscles that work in opposition to one another |
| prime mover | one muscle that plays the major role in accomplishing the desired movement |
| 2 tongue muscles | extrinsic and intrinsic |
| sternocleidomastoid | prime neck muscle |
| mastication | chewing |
| kissing muscles | orbicularis oris and buccinator |
| occipito frontalis | raises eyebrows |
| orbicularis occilu | closes eyelid |
| zygomaticus | smiling |
| levator labii superioris | sneering |
| depressor angulioris | frowning |