ABSTRACT
Natural muscles are elegant natural devices developed through millions of years of biological evolution
to transform chemical energy into mechanical energy and heat. The actuation of a natural muscle
(Figure 16.1) involves (a) aqueous media, (b) an electric pulse arriving from the brain (the pulse gen-
erator) to the muscle through the nervous system, (c) liberation of calcium ions inside the sarcomere,
(d) chemical reactions, (e) conformational changes along natural polymeric chains (actin and myosin)
with change of the sarcomere volume, and (f) water interchange. This natural motor can generate quite
elegant and gentle movements still never reproduced by any human-made motor. Moreover, the actuation
of the muscle involves simultaneous sensing processes providing the living being with a perfect con-
sciousness of both the characteristics of the mechanical movements and the physical interactions between
the organ moved by the muscle and its environment: they are intelligent devices.
