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contractility the ability of skeletal muscle to shorten with force.
excitability the capacity of skeletal muscle to respond to a stimulus.
extensibility the ability to be stretched.
elasticity ability to recoil to their original resting length after they have been stretched.
what do muscles help produce? Heat, essential for maintenance of normal body temperature.
epimysium (skeletal muscle) surrounded by connective tissue sheath.
fascia another connective tissue located outside the epimysium.(surrounds and separates muscles).
perimysium muscle composed of visible bundles called fasciculi (fascicle).
fibers single muscle cell.
endomysium (fiber surrounded) by connective tissue sheath.
myofibrils threadlike structure that extends from one end of the fiber to the other.
actin myofilaments thin myofilaments, they resemble 2 minute strands of pearls twisted together.
myosin myofilaments thick myofilaments. (resemble bundles of minute golf clubs)
sarcomeres joined end to end to form the myofibril.
what is the sarcomeres job? structural and functional unity of the muscle.
resting membrane potential charge difference across the membrane.
action potential reversal back of a charge.
motor neurons nerve cells that carry action potentials to skeletal muscle fibers.
neuromuscular junction branch that connects to the muscle.
synapse center of a cell.
motor unit a motor neuron
motor neuron nerve cells that carry skeletal muscle fibers
presynaptic terminal enlarged nerve terminal
synaptic cleft the space between the presynaptic terminal and the muscle cell
postsynaptic terminal muscle fiber
synaptic vesicles each presynaptic terminal contains this
acetylcholine secrete neurotransmitter
acetylcholinesterase breaks down enzymes
sliding filament mechanism sliding of actin during contraction
muscle twitch contraction of an entire muscle
threshold muscle fiber that will not respond to stimulus
all or none response this phenomenon is called (all or none response)
lag phase motor neuron and beginning of an contraction
contraction phase the time of a contraction
relaxation phase time of which muscles relax
tetany where muscles remain contracted with out relaxing
recruitment the increase in number of motor units being activated
energy requirements (4 of them) ATP, ATP, ATP, ADP
creatine phosphate necessary for muscle cells
anaerobic respiration without oxygen
aerobic respiration with oxygen (more efficient)
oxygen debt amount of oxygen needed in chemical reactions
muscle fatigue results when ATP is used during muscle contraction faster than it can be produced in the muscle cell
isometric equal distance
isotonic equal tension
muscle tone keeps head up and back straight
fast twitch fibers contract quickly and fatigue quickly
slow twitch fibers contract more slowly
origin (head) most stationary end of a muscle
insertion end of the muscle undergoing the greatest movement
belly portion of the 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 one muscle plays the major role in accomplishing the desired the desired movement
smooth muscle muscle tissue in which the contractile fibrils are not highly ordered, occurring in the gut or other internal organs
fascicle a bundle of structures, such as nerve or muscle fibers or conducting vessels in plants.
cardiac muscle heart muscle, one of the three major types of muscle, the others been skeletal and smooth
sarcolemma the fine transparent tubular sheath that envelopes the fibers of skeletal muscles.
sarcomere a structural unit of a myofibril in striated muscle, consisting of a dark band and the nearer
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. Trumpeter’s muscle.
two types of mouth muscles Orbicularis oris and buccinator are the kissing muscles.
Zygomaticus smiling muscle.
Levator labii superioris sneering
Depressor anguli oris frowning
Mastication chewing
4 pairs of mastication muscles: 2 pair of pterygoids, temporalis, and masseter
Intrinsic Tongue Muscles change the shape of the tongue
Extrinsic Tongue Muscles move the tongue
Neck Muscle Sternocleidomastoid
Sternocleidomastoid lateral neck muscle and prime mover. Rotates and abducts the head
Erector spinae group of muscles on each side of the back. Responsible for keeping the back straight and the body erect
Most involved in breathing External intercostals – elevate the ribs during inspiration. Internal intercostals – contract during forced expiration. Diaphragm
External intercostals elevate the ribs during inspiration
Internal intercostals contract during forced expiration
Diaphragm accomplishes quiet breathing
Created by: Heathermarie17



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