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
origin
fixed, immovable attachment; superior to insertion
insertion
movable attachment
prime mover
produces the movement (agonist)
antagonist
opposed or reverses movement
sygernist
reduces undesirable or unnecessary movement; aids prime mover
fixator
immobilizes origin of prime mover so all tension is exerted at insertion
flexion
bending at joint
extension
straightening at joint
adduction
toward body
abduction
away from body
lateral rotation
away from body
medial rotation
toward body
dorsiflexion
flexes foot
plantar flexion
points foot
inversion
foot inwards
eversion
ankle outwards
pronation
palm down
supination
palm up
7 criteria in naming muscles
- direction of muscle fibers
- size
- location
- number of origins
- location of origin and insertion
- shape
- action
importance of nerve supply and exercise in keeping muscles healthy
if the nerve supply is lost, the muscle is no longer stimulated; loses tone and leads to paralysis - flaccid
changes in aging muscles
connective tissue increases; muscle tissue and strength decreases; becomes stringy
nutrients to bones cells
perforating canals
central canals
canaliculi
lacuna (cave where bone cells live)
osteocyte (bone cell)
muscular system pt 2
maintains posture and body position
stabilizes joints
generates heat
myofibrils pt 2
made of proteins;
muscle fiber -> myofibril -> myofilaments
sliding filament theory
slide thin and thick over to shorten muscle; H and I temporarily disappear with overlapping
cross bridge cycle needs
calcium and atp for contraction
skeletal muscles function
irritability
contractibility
extensibility
elasticity
neurotransmitter
chemical released by nerve in axon terminal (acetylcholine)
hypertrophy vs atrophy
building; weakening
bursa
freely movable
posterior vs anterior
extender; flexor (front = flex)
flaccid
soft; hanging loosely
ALS (amyotrophic lateral sclerosis)
A nervous system disease that weakens muscles and impacts physical function
myasthenia gravis
a chronic autoimmune disorder in which antibodies destroy the communication between nerves and muscle, resulting in weakness of the skeletal muscles
anaerobic glycolysis
process of breaking down glucose in the absence of oxygen
opposition
resistance
lactic acid
produced in muscle cells and red blood cells
creatine phosphate
atp provides energy for a muscle contraction and is regenerated by direct phosphorylation by cp
muscles that move bones and are under conscious control
voluntary
muscle tissue that isn’t under conscious control
involuntary
acetylcholine
chemical released when nerve impulse reaches nerve ending
acetylcholine binds to the muscle cell membrane causing a temporary rush of what into muscle cell
sodium
acetylcholine binds to the muscle cell membrane causing a temporary rush of what into muscle cell
sodium
twitch
single contraction
aerobic respiration
lasts about 20 seconds; most energy at rest and light exercise
anaerobic respration
using glucose and other nutrient fuels; intense exercise - burning sensation
direction of muscle fibers
rectus abdominus
relative size
gluteus maximus
location
temporalis
number of origins
triceps brachii
location of origin and insertion
sternocleidomastoid
shape
deltiod
action
adductor Magnus
