Not every relation is a function. But every function is a relation. Function is just a part of relation.
The cubic function.
Range
The Mandelbrot graph is generated iteratively and so is a function of a function of a function ... and in that sense it is a composite function.
A formula or graph are two ways to describe a math function. How a math function is described depends on the domain of the function or the complexity of the function.
The myofilaments are actin and myosin.
Bundles of myofilaments make up
A myofibril is a bundle of contractile filaments (myofilaments), 1-2 μm in diameter, that are arranged in parallel groups in the cytoplasm of striated muscle cells.
Myosin
cardiac
The A band
I-Band
minimal overlap of thin and thick myofilaments.
sarcomeres are composed of myofilaments
the myofilaments themselves do not contract, they slide, this is called the Sliding Filament theory, in which the thick filament (Myosin) slides over the thin filament (Actin).
myofilaments
I Band