unit 6 Flashcards
skeletal muscle
attached to bone
striated
multinucleate
very long
voluntary
slow to fast contraction
no rhythm
attached by tendon to bone
*maintains body temp and stabilizes joints
smooth muscle
walls of hollow visceral organs
uninucleate
involuntary
very slow contraction
yes rhythm
cardiac muscle
shorter and branching
heart
striated
uninucleate
intercalated discs
involuntary
slow contraction
some rhythm
muscular system
contraction and shortening of muscles due to movement of microfilaments; moves bones and substances
endomysium
encloses a single muscle fiber; connective tissue (thin covering); fascia to tendons
perimysium
wraps around fascicle of muscle fibers
fascicle
bundle of muscle fibers
epimysium
covers entire muscle
tendon
cord; formed by fascia (outside of epimysium); collagen; crosses joints; connects muscle to bone
aponeurosis
sheet; specialized flat tendon; attaches indirectly to bone, cartilage, or connective tissue coverings
sarcolemma
specialized plasma membrane
myofibrils
long organelle inside muscle cell (a bands and I bands) that give striated look
a bands
myosin myofilaments; thick; heads form cross bridges to actin; full length of band
I bands
actin myofilaments; thin; attached to z disc; only a space
sarcoplasmic reticulum
stores and releases calcium; type of smooth; specialized endoplasmic reticulum
sarcomere
contracting unit of muscle fibers; extends from one z band to another
action potential
electrical current generated along muscle fiber membrane and is the signal to trigger a contraction
motor neuron
allows contraction
motor unit
one motor neuron and all skeletal muscle cells stimulated by that neuron
neuromuscular junction
gap between nerve ending and muscle cell
synaptic cleft
space between motor neuron and muscle fiber
axon terminal
end of nerve
motor end plate
position on cell where the nerve fiber connects
graded response
different degrees of skeletal muscle shortening
tetanus
response to prolonged stimulation; fused (complete-so rapid that no relaxation is detected) and unfused (incomplete-smoother and stronger)
isotonic contraction
myofilaments are able to slide past each other; shortening
isometric contraction
muscle filaments are pitted against immoveable object while trying to slide; can’t shorten past certain point
muscle tone
continuous low level of contraction; firm, healthy muscles
three pathways for atp regeneration during muscle activity
- direct phosphorylation of adp by creative phosphate
- aerobic pathway
- anaerobic glycolysis and lactic acid formation (burning muscles)
oxygen debt
rapid, deep breathing to restore oxygen
muscle fatigue
muscle activity is strenuous and prolonged; lack of oxygen
causes of muscle fatigue
lack of oxygen
decrease atp supply
ion imbalances
aerobic exercise
endurance; jogging; stronger, more flexible muscles with greater resistance to fatigue; helps digestions and metabolism and coordination
resistance exercise
isometric; weight lifting; increase in muscle size and strength