the acttin filament and myosin filament in detail Flashcards
bead like proteins which form a chain that is twisted back on itself
actin
made of 3 proteins
actin
the actin bead contains an active site for what use
so that the myosin head attaches to during muscle contraction
thread like protein that winds around the actin chain so that it covers the active sites when muscle is relaxed
tropomyosin
a protein that is attached to tropomyosin
troponin
what must bind to troponin before muscle contraction can take place
calcium
when calcium is present what does it do to troponin
it acts like a hand and pulls tropomyosin off of the active sites of the actin this allows the muscle contractions to start
is made up of 100s of golf club shaped
myosin
elongated portion of golf club found in H zone
myosin-rod tail
a bendable neck region that attaches the head to the rod causes swinging of the myosin head
hinge region
what is needed for the movement of the myosin head
atp
the sarcolemma has these hollow tube like structures that penetrate deep into muscle fibers and wind around the myofibrils whts the purpose
to carry electrical currents made by nerves from surface of the muscle cell to its center. this means that the electrical current reaches all myofibrils of the cell, not just the outer myofibrils so that they all contract within the muscle cell
what ensures that all the 1000 myofibrils inside the muscle cell contract so that the cell is fully contracted
t-tubules
a special organelle located between t-tubules that store calcium
sarcoplasmic reticulum
the cycle of calcium by sarcoplasmic reticulum
- when muscle is relax calcium is stored in SR
- to start a contraction calcium is released into muscle sarcomeres
- to stop contractions calcium is returned to the SR
