Events of muscle contractions by Jephthe Elisca

Event 1: Neuromuscular Junction

jephthe_elisca — 2018-01-12 16:04:09 UTC

When an action potential occurs Ca+ is released and this releases ACh into the cleft. Depolarization and repolarization occurs in which voltage gated Na+ release Na+ that floods in the cell and then voltage gated K+ release K+ that floods out of the cell to bring it back to resting membrane potential.

Event 2: EC Coupling

jephthe_elisca — 2018-01-16 15:28:53 UTC

Step 1: Action potential goes through sarcolemma and down the t tubules

Event 2: EC Coupling

jephthe_elisca — 2018-01-16 15:39:12 UTC

Step 2: When the action potential goes down the t tubules the SR release Ca+ which flow into the cytosol.

Event 2: EC Coupling

jephthe_elisca — 2018-01-16 15:43:16 UTC

Step 3 and 4: Ca2+ combines with troponin which changes the shape of tropomyosin that exposes the myosin binding sites are exposed. Myosin binds to the binding sites and creates a cross-bridge and contraction begins.

Event 3: Cross bridge coupling

jephthe_elisca — 2018-01-16 15:47:05 UTC

step 1: high-energy myosin heads attach to actin myofilaments to form cross bridge.

Event 3: Cross bridge coupling

jephthe_elisca — 2018-01-16 15:47:09 UTC

Step 4: energy form hydrolysis of ATP makes the head cock back into high-energy state

event 3: Cross bridge coupling

jephthe_elisca — 2018-01-16 15:47:14 UTC

Step 3: ATP attaches to myosin head which  the cross bridge.

Event 3: Cross bridge coupling

jephthe_elisca — 2018-01-16 15:47:18 UTC

step 2: release of ADP and inorganic phosphate causes myosin head to pivot and pull actin towards m line