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ch.6 muscles

able to shorten with force contractility
capacity of a skeletal muscle to respond to stimulus excitability
ability to be stretched extensibility
ability to recoil elasticity
connective tissue sheath that surrounds the skeletal muscle epimysium
connective tissue located outside of the epimysium fascia
loose connective tissue that covers the fascicle perimysium
fasciculi or fascicle are composed of single muscle cells called fibers
connective tissue sheath that covers each fiber endomysium
threadlike structure that extends from one end of the fiber to another myofibrils
thin myofilaments actin myofilaments
thick myofilaments myosin myofilaments
the basic structural and functional unit of the muscle sarcomere
charge difference across the membrane resting membrane potential
brief reversal back to charge action potential
nerve cells that carry action potentials to skeletal muscle fibers motor neurons
axons enter the muscles and and branch, each branch that connects to the muscle forms a what neuromuscular junction or synapse
single motor neuron and all the skeletal muscle fibers it innervates are called motor unit
enlarged nerve terminal presynaptic terminal
space between the presynaptic terminal and muscle cell synaptic cleft
the muscle between the presynaptic terminal postsynaptic terminal
synaptic vessicles secrete a neurotransmitter called acetylcholine
diffuses across he synaptic cleft and binds to the postsynaptic terminal causing a change in the postsynaptic cell acetylcholine
acetycholine released into the synaptic cleft between the neuron and muscle cell is rapidly broken down by an enzyme called acetylcholinesterase
sliding of actin myofilaments past myosin myofilaments during contraction is called sliding filament mechanism
contraction of an entire muscle muscle twitch
the point the muscle fiber will contract maximally threshold
time between application of a stimulus until that stimulus reaches a level called lag phase
time of contraction contraction phase
time during which the muscle relaxes relaxation phase
where the muscle remains contracted without relaxing tetany
increase in number of motor units being activated recruitment
needed for energy contraction, produced in the mitochondria atp (adenosine triphosphate)
the plus phosphate adp (adenosine diphosphate)
without respiration anaerobic respiration
with oxygen aerobic respiration
the amount of oxygen needed in chemical reactions to convert lactic acid to glucose oxygen debt
results when atp is used during muscle contraction faster than it can be produced in the muscle cells muscle fatigue
(equal distance) length of the muscle does not change isometric
(equal tension) amount of tension produced by the muscle is constant isotonic
refers to the constant tension produced by muscles of the body for long periods of time, keeps head up and back straight muscle tone
contract quickly and fatigue quickly fast-twitch fibers
contract more slowly and are more resistant to fatigue slow-twitch fibers
most stationary end of the muscle origin (head)
end of the muscle undergoing and greatest movement insertion
muscle between the origin and the insertion belly
muscles that work together to accomplish specific movements are called synergists
muscles that work in opposition to one another antagonists
if one muscle plays the major role in accomplishing the desired movement it is prime mover
occipitofrontalis raises the eyebrows
orbicularis oculi closes the eyelids and causes "crows feet" wrinkles in the skin at the lateral corners of the eye
orbicularis oris puckers the lips
buccinator flattens the cheeks
zygomaticus smiling muscles
levator labii superioris sneering
depressor anguli oris frowning
mastication chewing
intrinsic tounge muscles change the shape of the tounge
extrinsic tounge muscles move the tounge
lateral neck muscle, prime mover,rotates and abducts the head sternocleidomastoid
group of muscles on each side of the back, responsible for keeping back straight and body erect erector spinae
muscles that move the thorax thoracic muscles
elevate the ribs during inspiration external intercostals
contract during forced expiration internal intercostals
accomplishes quiet breathing, dome shaped muscle, aids in breathing diaphragm
rotates scapula trapezius
pulls scapula anteriorly serratus anterior
adducts and flexes arm pectoralis major
medially rotates, adducts, and powerfully extends the arm "swimmer muscles" latissimus dorsi
attaches the humerus to the scapula and clavicle, and is the major abductor of the upper limb deltoid
extends forearm, occupies posterior compartment of the arm triceps brachii
flexes forearm, occcupies anterior compartment of the arm biceps brachii
flexes forearm brachialis
flexes the wrist flexor carpi
extends the wrist extensor carpi
Created by: mackmarieee