Test Three Flashcards
titin
attaches myosin to the Z disc, stabilizes myosin from flipping
What is number 11?
I band
excitability
the ability of a muscle to be electrically stimulated
What is number 9?
H zone
Which band stays unchanged during muscle contraction?
A band
autorhythmic
“any cell that can open its own first sodium ion channel and start its own action potential”
What is the all-or-none principle?
“when a muscle is stimulated it will contract completely or not at all”
isotonic contraction
muscle shortens, (picking up a glass of TONIC water)
What are myoblasts?
Immature muscle cells
What is the main neurotransmitter?
acetylcholine
sarcolemma
muscle cell membrane
sarcoplasm
cytoplasm of muscle cell
What are the 8 steps to a muscle contraction?
- electrical stimulus must travel down the neuron
- this causes the synaptic vesicles to line up and release acetylcholine (into the synaptic cleft)
- acetylcholine opens a sodium ion channel on the motor end plate of the muscle cell
- sodium ions fly into the cell, starting an action potential
- the action potential causes the sarcoplasmic reticulum to release calcium ions
- calcium ions pull off troponin and roll back the tropomyosin. this opens up the myosin head binding sites
- ATP is broken down on the myosin head, this energy is put into the myosin head, popping it into the binding site(on both sides of the M-line)
- both energized heads engage and power stroke (rotate) pulling the Z-discs closer together
extensibility
muscle can be stretched without damaging the muscle
What is attached to the dense bodies?
intermediate filaments
What are the 5 sarcomere bands/lines/zones?
- H zone- center of any sarcomere -A band-center part of a sarcomere that contains the whole myosin filament (and parts of actin filaments) -I band- only contains actin -Z disc- ends of the sarcomere -M line- middle thick bit, stops actin from contracting too far (think of it as a parking block)
What is complete tentanus and what is the contraction rate?
no relaxtion period between contractions, EMERGENCY ONLY; 80-100 times a second
tropomyosin
“wraps around thin filaments (actin) in relaxed muscle”
What is the contraction phase?
cell depolarizes, making charges equal on both sides
Is myosin thick or thin and does it slide or rotate?
thick, rotate
What organs do skeletal muscles make up and what does this muscle look like?
voluntary muscles; long fibers, striated
creatine kinase
shuttles phosphate from creatine to ADP for use when extra energy is needed fast
What is the refractory phase?
the cell is COMPLETELY depolarized, “at this refractory phase the cell has lost its membrane potential and can’t respond to a stimulus from another neuron”
motor unit
“a single motor neuron and all the muscle cells it associates with”
Who are the contractile proteins?
actin and myosin
What controls cardiac muscles?
autorhythmic
dendrites
carry signal to a cell body in a neuron
What are the 4 qualities of cardiac muscle?
-involuntary -highly elongated -intercalated discs -autorhythmic
What is number 2?
actin
axon
carries signal away from the cell body in a neuron
What is the perimysium and what type of tissue is it made of?
wraps around FASICICLES (bundles of 10-100 muscle cells) (dense irregular CT)
What controls smooth multi unit muscles?
nerves