Exam 2 (muscles) Flashcards
(33 cards)
T-tubule
action potential goes deep into muscle bed
triggers ca2+ release
delay b/w action potential and muscle contraction
time required for ca2+ to be released and bind to troponin
twitches can also play a factor
sliding filament theory
thick and thin filaments do not change length, but slide past one another
functions of skeletal muscle
support
kinectic energy
thermoregulation
myosin
binds actin and ATP
thick filament
sarcoplasm
cytoplasm
actin
thin filament
titin
allows sarcomere to go back to original form
largest protein known
thick filament
stays the same
thin filament
changes size
ATP hydrolysis
conformation change
no ATP
no contraction (rigor mortis)
benefits of 2 binding sites
smoother contraction
Ca2+
allows for the formation of crossbridges
slow twitch
less mitochondria
for posture
found in dark meat
generate ATP through oxidative phosphorylation
sustained contraction
more common in athletes
builds endurance
fast twitch
for standing or walking
more mitchondria
found in white meat
fast
high ca2+ ATPase activity in SR
pheripheral fatigue
changes in NMJ, MMP, calcium signaling
depletion of certain metabolites, ATP
glycogen accumulation of certain metabolites
low pH, lactate
force
determined by frequency of muscle action potentials and stimulation of the muscle fiber
motor unit
consists of one motor neuron and all the muscle fibers it innervates
may have many motor units of different types
smooth muscle
vascular
gastrointestinal
urinary
respiratory
reproductive
ocular
no sarcomeres
actin more abundant
longer mysoin heads
no tropnin
uses calmodulin
gap junctions
allow contraction to occur as a whole unit
lack of gap junctions
allow contraction to occur independently
MLC
myosin light chains
MLCK
kinase which increases myosin ATPase activity
