https://padlet.com/karmoo680/l8fe1himsr3 Made with a curious mind en-us 2019-03-11 11:44:22 UTC 2025-08-03 13:18:30 UTC hello@padlet.com karmoo680 https://padlet.com/karmoo680/l8fe1himsr3/wish/339892502 A nerve impulse is sent down the axon terminal to the neuromuscular junction.  The nerve impulse causes voltage gated calcium ion channels to open, allowing calcium ions to enter the neuron. Acetycholine is then released into the cleft.  ACh then binds to a receptor site and activates the voltage gated sodium channel. This pumps Na+ ions in and K+ ions out which causes it to depolarize. Depolarization spreads which causes voltage gated sodium channels to open which will then initiate action potential that travels down the sarcolemma.  A change in the membrane permeability is caused by Na+ concentrations.  This opens the voltage gated K+ ion channels which will allow K+ ions to diffuse across the sarcolemma.  This process is repolarization.]]> 2019-03-11 11:50:56 UTC https://padlet.com/karmoo680/l8fe1himsr3/wish/339892502 karmoo680 https://padlet.com/karmoo680/l8fe1himsr3/wish/339892570 Step 1:  An action potential moves down the sarcolemma and T- tubules.]]> 2019-03-11 11:51:05 UTC https://padlet.com/karmoo680/l8fe1himsr3/wish/339892570 karmoo680 https://padlet.com/karmoo680/l8fe1himsr3/wish/339892727 step 1: The myosin head attaches to an actin myofilament which creates the cross bridge.

]]> 2019-03-11 11:51:28 UTC https://padlet.com/karmoo680/l8fe1himsr3/wish/339892727 karmoo680 https://padlet.com/karmoo680/l8fe1himsr3/wish/339892772 Step 2: Transmission of the action potential along the T-tubules causes the adjacent sarcoplasmic reticulum to release Ca2+. This then flows into the cytosol.]]> 2019-03-11 11:51:35 UTC https://padlet.com/karmoo680/l8fe1himsr3/wish/339892772 karmoo680 https://padlet.com/karmoo680/l8fe1himsr3/wish/339892838 Step 3 and 4: Ca2+ then combines with troponin & removes the blocking action of tropomyosin by changing the shape of the actin.  The myosin binding sites are exposed. Myosin the binds to actin to form cross bridges and contraction begins.]]> 2019-03-11 11:51:44 UTC https://padlet.com/karmoo680/l8fe1himsr3/wish/339892838 karmoo680 https://padlet.com/karmoo680/l8fe1himsr3/wish/339892874 Step 4: ATP is hydrolyzed to the ADP & P. Myosin head returns to the prestroke state or cocked position. ]]> 2019-03-11 11:51:51 UTC https://padlet.com/karmoo680/l8fe1himsr3/wish/339892874 karmoo680 https://padlet.com/karmoo680/l8fe1himsr3/wish/339892921 Step 3: The ATP attaches to myosin weakening the bond between the myosin and actin. The myosin head then detaches ]]> 2019-03-11 11:51:56 UTC https://padlet.com/karmoo680/l8fe1himsr3/wish/339892921 karmoo680 https://padlet.com/karmoo680/l8fe1himsr3/wish/339892970 step 2: ADP & P are released causing the myosin head to pivot. The change in shape results in the actin filament to be pulled towards the M line.]]> 2019-03-11 11:52:03 UTC https://padlet.com/karmoo680/l8fe1himsr3/wish/339892970