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Chapter 6: Muscles

contractility ability to shorten with force
Excitability responding to stimulus
extensibility ability to be stretched
elasticity ability to recoil
epimysium connective tissue that surrounds skeletal muscle
fascia tissue surrounds & separates muscles
perimysium surrounds muscle fascicle
endomysium covers muscle fibers
muscle cells muscle fibers
myofibrils thread like structure
actin myofilaments thin myofilaments
myosin myofilaments thick myofilaments
sacromere basic structural & functional unit of muscles
Z line attachment site for actin
I band light side of the Z line
A band darker central region, filled with myosin.
H zone center of each sacromere
M line dark staining band
Resting Membrane Potential charge difference across the membrane
Action Potential reversal of a charge.
Motor Neurons nerve cells that carry action potentials to skeletal muscle fibers.
Neuromusclular junction/ Synapse formed when branches connect to muscle, near center of cell.
Motor Unit Single motor neuron & all skeletal muscle fibers operating
Presynaptic Terminal Enlarged nerve terminal
Synaptic Cleft space between the presynaptic terminal & the muscle cell.
Postsynaptic Terminal muscle fiber
Synaptic Vesicles secrete a neurotransmitter called acetylcholine
Acetylcholine Binds to the postsynaptic terminal causing a in postsynaptic cell.
Acetylcholinesterase Enzyme that breaks down muscle cells
Muscle contraction When the sarcomere shortens, it cause the muscle to shorten.
Sliding Filament Mechanism When actin and myosin myofilaments glide past one another.
Muscle twitch contraction of a muscle ins response to s stimulus
Threshold when the muscle fiber will contract maximally.
Lag phase time between response to a stimulus & actual contraction
Contraction phase the time of contraction
Relaxation Phase the time when muscle relaxes fully
Tetany where the muscle remains contraction without relaxing.
Recruitment increase in number of motor units being activated
Adenosine Triphosphate (ATP) is needed for energy to contract muscles
Creatine Phosphate high-energy molecule, used to replace ATP
Anareobic Respiration without oxygen
Aerobic Respiration with oxygen
Oxygen Debt amount of oxygen needed to replenish the depleted store of CP stores in muscle cells
Muscle Fatigue results when you use more muscle cells faster than you can reproduce.
2 types of muscle contractions isometric & isotonic
Isometric when length doesn't change but the tension increases.
Isotonic tension doesn't change, but length does.
Muscle Tone constant tension produced by muscles of the body for long periods of time.
Fast-Twitch Fibers Contract quickly & fatigue quickly
Slow-twitch Fibers contract slowly & are more resistant to fatigue.
Muscle is connected to the ____ by the ______. bone ; tendon
Origin (head) most stationary end of the muscle
Insertion end of muscle undergoing most movement
Belly portion of muscle between the origin & insertion
Some muscles have multiple _____. origins
Synergists muscles that work together to accomplish a specific movement
Antagonists muscles that work in opposition to each other.
Prime mover In a group of synergists, one muscle that plays the major role
Muscles help produce ____ essential for maintenance of body temperature. heat
Muscle fasciculi (fascicle) numerous visible bundles
Muscle fibers single cylindrical cell containing several nuclei
2 major kinds of protein fibers actin & myosin
Created by: jeanie_beanie