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59 Cards in this Set
- Front
- Back
why are muscles important
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responsible for movement of the body and all its joints,
protection postural maintenance produce a major portion of body heat |
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how many pairs of skeletal muscle
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215 pairs
make up 40 to 50 percent |
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Shape and fiber arrangement help determine
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the abilty of the muscle to exert force and the range of motion over which it can exert that force
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larger cross-sectional area=
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greater force production
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longer muscles=
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greater range of motion (increased ability to shorten)
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Parallel muscle
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long muscles, with increased ability to shorten and greater ROM
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Pennate Muscles
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Shorter muscle fibers with oblique orientation to tendons
increased cross sectional area resulting increased force produced |
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Parallel ROM shapes and arrangements
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flat (rectus abdominis)
fusiform (bicep brachii) strap (sartorius) radiate (pectoralis major) sphincteral (orbicularis oculi) |
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pennate power shapes and arrangements
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unipennate - biceps femoris
bipennate - rectus femoris multipennate - deltoid |
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intrinsic uscle
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within or belonging to body part acting (hand/foot muscles)
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extrinsic muscle
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originate ouside body part acting
usually proximal to body part |
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action muscle
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specific movement of joint from contraction
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innervation
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portion of the nervous system responsible for muscle movement
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origin
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prosimal, closest to midline, least movable part
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insertion
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distal, farthest from midline, most movable
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isometric contraction
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tension with constant joint angle (static, stable position)
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isotonic contraction
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tension with joint movement
dynamic, varying degrees of tension through movement |
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two types of isotonic contraction
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concentric and eccentric
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concentric
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tension with muscle shorteing
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eccentric
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tension lessens causing muscle lengthening
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Agonist
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causes joint movement (primary movers)
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antagonist
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opposite side of joint from agonist (work with agonist by relaxing)
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stabilizer
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surround joint, contract to fixate joint
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synergist
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assist with agonist but not prime mover,
refined movement, no undesired action |
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lines of pull
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resultant movement produced at a joint contraction
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to determine muscle action via line of pull
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must know origin and insertion of muscle
plane of movement for specific joint position of muscle relative to axis of joint muscles relative length through ROM |
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cerebral cortex creates
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voluntary movement
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basal ganglia
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postures and equilibirum
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cerebellum
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feedback relative to motion
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brain stem
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arousal/wakeful state
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spinal cord
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pathway between peripheral nervous system and cns
specific control an integrates spinal reflexes |
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skeletal muscle has four properties related to its ability to produce force and movement about joints
what are they? |
irritability
contractility extensibility elasticity |
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irritability
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property of muscle being sensitive or responsive to chemical, electrical, or mechanical stimuli
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contractility
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ability of muscle to contract and develop tension or internal force against resistance when stimulated
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extensibility
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bility of muscle to be passively stretched beyond its normal resting length
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elasticity
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ability of muscle to return to its original length following stretching
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epimysium
perimysium vasciculus endomysium muscle fiber (cell) |
j
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sarcomere is composed of
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zline
actin filaments myosin heads myosin filaments |
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motor unit
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each motor neuron together with the muscle fibers it innervates
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number of muscle fibers contracting within the muscle may vary significantly from relatively few to virtually all depending on the
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number of muscle fibers within each activated motor unit and the number of motor units activated
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difference between lifting a minimal vs. maximal resistance is
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the number of muscle fibers recruited
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muscle fibers recruitment increased by
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activating motor units with a greater number of muscle fibers
activating more motor units increasing the frequency of motor unit activation |
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greatest amount of tension can be developed when a muscle is stretched between
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100 to 130 percent of its resting length
beyond wich the force exerts decreases significantly |
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proportional decrease in ability to develop tension occur as a muscle is shortend around
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50 to 60 percent of resting length ability
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active insufficiency
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muscle becomes shortened to the point that it can not generate or maintain active tension
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passively insufficiency
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muscle becomes stretched to the point where it can no longer lengthen and allow movement
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concentric velocity and force production has a ....relationship
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inverse relationship
as force needed to cause movement of object increases the velocity of concentric contraction decreases Heavy stuff takes a while to lift |
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eccentric velocy has a somewhat proportional relationship with force needed
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force needed to control objects movement increases, the velocity of eccentric lengtheing increases
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reciprocal inhibition or innervation
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antagonist gotta chill while agonist does its work yo
...activation of the motor units of te agonists causes a reciprocal neural inhibition of the motor unnits of the antagonists |
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proprioceptors
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gather info about position and movements of body
located in muscle, tendons, joints |
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muscle spindles
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responsive to length- tonic response
rate of change in length- phasic response |
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golgi tendon organs
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embedded in muscle tendon
responsive to tesnsion in muscle -inhibition of contraction |
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joint and skin proprioceptors
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pacinian corpuscles
ruffini corpuscles |
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pacinian
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in skin, joint capsules, ligaments, tendon sheaths
detect rapid changes in pressure heavy touch |
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ruffini corpuscles
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located in skin and joint capsule
contiuous states of pressure, joint position, changes in joint angle, detect touch, pressure |
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tendon reflex
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golgi tendon organ overrides muscle spindle,
extreme tension causes lengtheing reaction to protect muscles, tendons |
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reciprocal inhibition and coactivation
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provide for economical, coordinated movement (occurs automatically with stretch reflex
muscle coactivation with uncertain movements, maintains joint stiffness until skill increases leading to reciprocal inhibition |
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dermatome
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defined area of skin supplied by a specific spinal nerve
afferent pathway senses cold/hot, pin prick, soft |
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myotome
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muscle or group of muscles motor function supplied by a spcific spinal nerve
innervation of movements efferent pathway used to assess motor spinal nerve involvement |