https://padlet.com/jussay758/usxlguq7iu16 Tells you how muscles contract en-us 2019-03-08 13:18:31 UTC 2024-07-18 17:46:58 UTC hello@padlet.com jussay758 https://padlet.com/jussay758/usxlguq7iu16/wish/339276057 The brain sends an action potential down to the neuromuscular junction (Where the axon terminal meets the muscle cell).This action potential opens up voltage gated calcium ion channels , and the calcium ions then stimulate the release of acetylcholine. Acetylcholine binds to receptor sites, and activates voltage- gated Na+ ion channels. The voltage gated Na+ ion channels pump Na+ and K+ out. Since more Na+ is pumped in than K+ is pumped out, the cell becomes less negative or depolarized. As one area of the sarcolemma becomes depolarized it causes voltage gated Na+ channels in adjacent area to open which leads to depolarization going down the entire sarcolemma.After depolarization the Na+ concentrations leads to the opening of voltage gated K+ ion channels which allow K+ to diffuse out of the muscle fiber( this process is known as repolarization.]]> 2019-03-08 13:19:36 UTC https://padlet.com/jussay758/usxlguq7iu16/wish/339276057 jussay758 https://padlet.com/jussay758/usxlguq7iu16/wish/339276123 Step 1:  Transmission of an action potential along the sarcolemma leads to the release of calcium ions from the sarcoplasmic reticulum, and the sliding of myofilament. This action potential moves down the T tubules 

 

]]> 2019-03-08 13:19:47 UTC https://padlet.com/jussay758/usxlguq7iu16/wish/339276123 jussay758 https://padlet.com/jussay758/usxlguq7iu16/wish/339276221 Step 2: Transmission of the action potential along the T tubules cause the adjacent sarcoplasmic reticulum to release Ca2, which flows into the cytosol.]]> 2019-03-08 13:20:04 UTC https://padlet.com/jussay758/usxlguq7iu16/wish/339276221 jussay758 https://padlet.com/jussay758/usxlguq7iu16/wish/339276329 Step 3 and 4: Ca2 combines with troponin and removes the blocking action of tropomyosin by changing the shape of the actin so that the myosin binding sites are exposed. Afterwards myosin binds to actin to form cross bridges and muscle contraction begins. 

]]> 2019-03-08 13:20:22 UTC https://padlet.com/jussay758/usxlguq7iu16/wish/339276329 jussay758 https://padlet.com/jussay758/usxlguq7iu16/wish/339276436 step 1: The active sites are exposed and ready for myosin binding.

]]> 2019-03-08 13:20:42 UTC https://padlet.com/jussay758/usxlguq7iu16/wish/339276436 jussay758 https://padlet.com/jussay758/usxlguq7iu16/wish/339276585 step 2: working stroke- the myosin head pivots and bonds as it pulls on the actin filaments sliding it towards the m line.]]> 2019-03-08 13:21:06 UTC https://padlet.com/jussay758/usxlguq7iu16/wish/339276585 jussay758 https://padlet.com/jussay758/usxlguq7iu16/wish/339276777 Step 3: New ATP attaches to the myosin head, which causes the cross bridge to detach.]]> 2019-03-08 13:21:40 UTC https://padlet.com/jussay758/usxlguq7iu16/wish/339276777 jussay758 https://padlet.com/jussay758/usxlguq7iu16/wish/339276907 Step 4: ATP is turned into ADP through hydrolysis, and the the cocking of the myosin head occurs. ]]> 2019-03-08 13:22:03 UTC https://padlet.com/jussay758/usxlguq7iu16/wish/339276907