Main Question or Discussion Point
I know muslces have fibers and all sorts of structures but how do they actually attract themselves to each other on a very atomic level? Is it some sort fo chemical bonding force or?
Nice post, so would you say it would be something like an ionic bond contracting the muscles?Its a complex process involving many changes in binding and changes in the shape of proteins that make up the fibers in the muscle cells.
Generally speaking, the binding of between two interacting proteins is not that strong. However, it would be repeated many many times in each muscle fiber where thousands or millions of interacting proteins would be involved. Binding sites are usually made by a mix of different weak interactions on the 3D surfaces of the two things being bound together. They usually don't involve covalent bonds, but may involve charge and other interactions.
The binding of two proteins may cause one or both proteins to change shape.
In addition to these general considerations on binding, ATP (cellular energy source) is involved in muscle contraction by driving certain changes in the protein shape. Shape changes such as this, in turn involve relatively weak interactions within the particular proteins, which drives their shape changes, which in turn causes muscle contraction.
It is usually triggered by an increase in Ca++ whihc binds to particular muscle proteins.
Muscles actively contract (shorten). They lengthen passively (no energy involved, no force generated, other muscles contraction causes them to lengthen).
Wikipedia has a extensive article in this. See the article for more details.
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Picture from here.