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Chapter 6 muscle voc
anatomy/physiology
contractibility | ability of skeletal muscles to shorten with force |
excitability | capacity of skeletal muscle to respond to a stimulus |
extensibility | ability to be stretched |
elasticity | ability to recoil to their original resting length after they have been stretched |
epimysium | skeletal muscle surrounded by a connective tissue |
fascia | connected tissue located outside the epimysium |
perimysium | loose connective tissue |
fibers | single muscle cells |
endomysium | connective tissue sheath |
myofibrils | threadlike structure that extends from one end of the fiber to the other |
actin myofilaments | thin mylofilaments |
myosin myofilaments | thick mylofilaments |
sarcromeres | basic structural and functional unity of the muscle |
resting membrane potential | the charge difference across the membrane |
action potential | brief reversal back of the charge |
motor neurons | nerve cells that carry action potentials to skeletal muscle fibers |
neuromuscular junction | each branch that connects to the muscle |
synapse | branch that connects to the muscle near the center of the cell |
motor unit | single motor neuron and all the skeletal muscle fibers it innervates |
presynaptic terminal | enlarged nerve terminal |
synaptic cleft | space between the presynaptic terminal and the muscle cell |
postsynaptic terminal | muscle fiber |
synaptic vesicles | secrete a neurotransmitter |
acetylcholine | secretion of a nuerotransmitter |
acetylcholinesterase | enzyme that breaks down acetylcholine |
sliding filament mechanism | the sliding of actin mylofilaments past myosin myofilaments during contraction |
muscle twitch | a contraction of an entire muscle in response to a stimulus |
threshold | the level to which a stimulus much reach for a muscle fiber to respond |
all-or-none response | point in which the muscle fiber will contract maximally |
lag phase | time between application of a stimulus to a motor neuron and the beginning of a contraction |
contraction phase | time in which the muscle contracts |
relaxation phase | time in which the muscle relaxes |
tetany | muscle remains contracted without relaxing |
recruitment | increase in number of motor units being activated |
ATP | adenosine triphosphate |
ADP | adenosine diphosphate |
creatine phosphate | a high end molecule |
anaerobic respiration | without oxygen |
aerobic respiration | with oxygen |
oxygen debt | amount of oxygen needed in chemical reactions to convert lactic acid to glucose |
muscle fatigue | results when ATP is used during muscle contraction faster than it can be produced |
isometric | length of muscle does not change, but the amount of tension increases during the contraction process |
isotonic | amount of tension produced by the muscle is constant during contraction |
muscle tone | refers to 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 | the most stationary end of the muscle |
insertion | the end of the muscle undergoing the greatest movement |
belly | portion of muscle between the origin and the insertion |
synergists | muscles that work together to accomplish specific movements |
antagonists | muscles that work in opposition to one another |
prime mover | muscle that plays the major role in accomplishing the desired movement |
occipitofrontalis | raises the eyebrows |
orbicularis occuli | closes the eyelids and causes "crows feet" |
orbicularis oris | puckers the lips |
buccinator | flattens the cheeks |
zygomaticus | smiling muscle |
levator labii superioris | sneering |
depressor anguli oris | frowning |
intrinsic tongue muscle | changes the shape of the tongue |
extrinsic tongue muscle | moves the tongue |
sternocleidomastoid | lateral neck and prime mover. rotates and abducts the head |
thoracic muscles | muscles that move the thorax |
diaphragm | accomplishes quiet breathing. dome shaped muscle that aids in breathing |
trapezius | rotates scapula |
serratus anterior | pulls scapula anteriorly |
pectoralis major | adducts and flexes the arm |
latissimus dorsi | medially rotates, adducts, and powerfully extends arm |
deltoid | attaches the humerus to the scapula and clavicle, and is major abductor to the upper limb |
triceps brachii | extends the forearm |
biceps brachii | flexes the forearm |
brachialis | flexes forearm |
flexor carpi | flexes the wrist |
extensor carpi | extends the wrist |
flexor digitorum | flexes the fingers |
extensor digitorum | extends the fingers |