What is the name for the linkage that forms between actin and myosin during muscle contraction?

The name for the linkage that forms between actin and myosin during muscle contraction is called a Cross-Bridge.

Here are the steps of how it forms:

1. The process begins when a nerve impulse reaches the muscle fiber. This causes the release of calcium ions.

2. The calcium ions bind to a protein called troponin, which is located on the actin filament. This causes a shift in another protein called tropomyosin, which normally blocks the binding sites for myosin on the actin filament.

3. Once the binding sites are exposed, the myosin heads can bind to the actin filament, forming a cross-bridge.

4. After the cross-bridge is formed, the myosin head pivots, pulling the actin filament towards the center of the sarcomere. This is what causes the muscle to contract.

5. ATP (adenosine triphosphate) then binds to the myosin head, causing it to detach from the actin filament.

6. The ATP is then broken down into ADP (adenosine diphosphate) and a phosphate group, which provides the energy for the myosin head to return to its original position.

7. The process can then start again, leading to further muscle contraction.