w8 exercise physiology Flashcards
what is pair of muscles that can pull the same bone in opposite directions
antagonists
what are fascicles
a bundle of structures, such as nerve or muscle fibers or conducting vessels in plants
what makes up muscle
fasicles
myofibrils
basic rod-like organelle of a muscle cell
actin and myosin which is thick or thin
actin - thin
myosin - thick
Z lines contain what protein and do what
alpha-actinin
defines the lateral boundaries of the sarcomere and anchores thin, titin and nebulin filaments
dark area between 2 Z lines that contains what filaments
A band, thick and thin filaments
light band either side of Z line and contains what filaments
I band, contains thin filaments
light area located in the middle of A band and contain what filaments
thick filaments
dark line in middle of sarcomere that contains what proteins that are critical for organization and alignment of thick filaments
M line, myomesin protein, thick filaments
thin filaments include what
actin, troponin, and tropomyosin
what plays a key role in regulating muscle contraction
troponin and tropomyosin
what does the alkali light chain do of myosin muscle
stablize myosin head
what does the regulatory light chain do of myosin muscle
regulate APTase activity of myosin
when does a muscle contract
when thin filaments slide along thick filaments
signals from what system, conveyed by what are required to initiate and sustain muscle contraction
signals from CNS, conveyed by motor neurons
when a motor neuron sends out an action potential, its synaptic terminals release what neurotransmitter, which diffuses across the synapse to the plasma membrane of the muscle fiber
acetylcholine
what is released from the ER when a motor neuron stimulates muscle contraction
Ca2+
action potential causes channels in the ER to open, releasing what where
releasing Ca2+ into the cytoplasmic fluid
when muscle fiber is in resting state, what blocks what
tropomyosin and tropnin block myosin binding sites on the actin molecules
Ca2+ allows what as it binds to what
Ca2+ binds to troponin, and tropomyosin moves away from the myosin binding site, allowing contraction to occur
the motor unit consist of what
a single motor neuron and all the muscle fibers it activates (one set of muscle fibers)
a typical skeletal muscle receives innervation from approx how many somatic motor neurons
100
a motor neuron pool consist of what
many motor neurons, each of which innervates a motor unit w the muscle
motor units are recruited in progressive order from
smallest (weakest) to largest (strongest)
Type I and Type IIa/IIb is fast or slow
Type I - slow twitch
Type II - fast-twitch
slow twitch and fast twitch mitochondrial content high or low and fatigue level
slow - high mitochondrial content, slow rate of fatigue
fast - low mitochondrial content, rapid rate of fatigue
does strength or endurance training increase capillary supply and mitochondrial content
endurance training