https://padlet.com/makmoy922/9ovaumw6q2xi Three major events of muscle contraction en-us 2019-03-08 14:07:48 UTC 2024-11-03 22:36:41 UTC hello@padlet.com makmoy922 https://padlet.com/makmoy922/9ovaumw6q2xi/wish/339298442 In event 1 the brain sends a nerve impulse aka action potential that goes through the neuromuscular junction. The nerve impulse causes voltage gated Ca+ ion channels open which lead to Ca+ entering the cell. This stimulates the release of acetylcholine which is released in the cleft. The ACh binds to the receptor that then activated voltage gated Na+ channels that pump Na in and K out. This makes the interior of the cell less negative. The initial depolarization spreads opening the voltage gated Na channels which causes an action potential. The Na contractions stimulate a change in the membrane permeability by opening K pumps this allow K to diffuse across the sarcolemma and out the muscle fiber.]]> 2019-03-08 14:09:23 UTC https://padlet.com/makmoy922/9ovaumw6q2xi/wish/339298442 makmoy922 https://padlet.com/makmoy922/9ovaumw6q2xi/wish/339298496 The action potential moves down the sarcolemma and down the T tubules.

 

]]> 2019-03-08 14:09:30 UTC https://padlet.com/makmoy922/9ovaumw6q2xi/wish/339298496 makmoy922 https://padlet.com/makmoy922/9ovaumw6q2xi/wish/339298527 The transmission along the T tubules causes the adjacent sarcoplasmic reticulum to release Ca2+ which flows into the cytosol. ]]> 2019-03-08 14:09:34 UTC https://padlet.com/makmoy922/9ovaumw6q2xi/wish/339298527 makmoy922 https://padlet.com/makmoy922/9ovaumw6q2xi/wish/339298614 Ca2+ combines with troponin and removes the blocking action of tropomyosin by changing shape of the actin so that the myosin binding sites are exposed. The myosin binds to actin to form across bridges and contraction then begins

]]> 2019-03-08 14:09:43 UTC https://padlet.com/makmoy922/9ovaumw6q2xi/wish/339298614 makmoy922 https://padlet.com/makmoy922/9ovaumw6q2xi/wish/339298713 Cross bridges formation energized myosin head attaches to an actin myofilament forming cross bridges.

]]> 2019-03-08 14:09:55 UTC https://padlet.com/makmoy922/9ovaumw6q2xi/wish/339298713 makmoy922 https://padlet.com/makmoy922/9ovaumw6q2xi/wish/339298748 The power stroke. ADP and Pi are released the myosin head pivots and bends changing to its bent low energy state. As a result it pulls the actin filament toward M line.]]> 2019-03-08 14:10:00 UTC https://padlet.com/makmoy922/9ovaumw6q2xi/wish/339298748 makmoy922 https://padlet.com/makmoy922/9ovaumw6q2xi/wish/339298828 Cocking of the myosin head as ATP is hydrolyzed to ADP and Pi the myosin head returns to its prestroke high-energy or cocked position]]> 2019-03-08 14:10:08 UTC https://padlet.com/makmoy922/9ovaumw6q2xi/wish/339298828 makmoy922 https://padlet.com/makmoy922/9ovaumw6q2xi/wish/339298935 Cross bridge detachment after ATP attaches to myosin the link between myosin and actin weakens and the myosin head detaches ]]> 2019-03-08 14:10:16 UTC https://padlet.com/makmoy922/9ovaumw6q2xi/wish/339298935