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Muscles

Terms in this set (50)

Skeletal
voluntary, striated, multinucleated
smooth
involuntary, non-striated, 1 nucleus
cardiac
involuntary, striated, 1 nucleus, intercalated discs
fascicles
bundles of muscle fibers
Fibers
aka cells
Myofibril
fibers within the cell
Myofilaments
fibers within the myofibril
2 types of myofilaments
myosin (thick) and actin (thin)
contractile proteins
actin and myosin
muscles layers are surrounded by
Connective tissue
Endomysium
around muscle fiber(cell)
Perimysium
around fascicle
Epimysium
around whole muscle which forms tendons
why does muscle have coverings?
cushion/ prevents break down from rubbing
Sarcolemma
muscle fiber
muscle fiber
invaginations from T-tubules that enter the cell membrane
sarcoplasm
inner material surrounding fibers (like cytoplasm)
sarcoplasmic reticulum (SR)
stores calcium
Myofibrils
contain the myofilaments parallel, fibers
A band
dark- myosin and actin
I band
light- actin only
sarcomere
functional unit of muscle contraction -Z disc
sliding filament theory
theory of how muscle contracts, theory tells how the actin and myosin filaments slide past one another to allow a muscle to contract
neuronuscular junction
where a nerve and muscle fiber come together
T tubules
carries the electrical current to interior of cell( invagination of sarcolemma)
Smooth Endoplasmic Reticulum
aka sarcoplasmic- stores neurotransmitters(Ach)
ach
Synoptic vessels contain a neurontransmitter called
hypertrophy
muscle enlarges, working out of certain disorders
concentric
contraction while muscle is shortening, ex-biceps
origin
immovable end of a muscle
insertion
movable end of a muscle
agonist
chiefly responsible for a particular movement( prime/ main mover)
Anatagonist
opposes the agonist
atrophy
muscles become small and weak due to disuse , happens whne it is not being regularly stimulated by a nerve
eccentric
contraction accompanied by lengthening of a muscle, ex- triceps
rigor matis
few hours after death, the joints of the body stiffen and become locked in place
Lasts approximately 72 hours
motor neurons
provide voluntary movements and muscle control
ALS
amyotrophic lateral sclerosis, a progressive neurodengerative disease
musclar dystrophy
muscles progessively get weaker, often resulting in inability to walk(boys)
myasthenia gravis
"Grave muscular weakness"
autoimmune disease, Acetylcholine receptors are damaged
symptoms—- dropping eyelid, blurred vision, weakness
myotonia
delayed relaxation of the skeletal muscles after muscle contraction
tetanus
A bacterial infection caused by Clostridium tetani
toxin produced by this makes persons muscles contract and not relax—- spastic paralysis
curare
classified as a neurotransmitter blocking agent—- it produces flaccidity in skeletal muscle by competing with the neeurotransmitters ACH at the neuromuscular junction
Botulism
blocks ACH release- muscles get weak "flaccid paralysis"
Botox
weakened botulism toxin- reduces wrinkles used for other conditions
strychnine
Lowers the threshold level for an action potential, making it more likely the muscles will contract
strychnine death
occurs from convulsions and asphyxia
Ach
what neurotransmitter is associated with muscle contraction?
ATP
what form of energy is responsible for muscle contraction and relaxation?
Acetyl Choline (ACh)
vesicles are the end of a nerve store what substance?
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