Page 98 - The Miracle of Electricity in the Body

96 THE MIRACLE OF ELECTRICITY IN THE BODY

Actions That Take Place with Electrical Current

When you want to move a finger, countless nerve cells in your
brain start sending minute electrical signals to one another. These cur-
rents are later transmitted from the brain to the arm, by means of the
medulla oblongata and spinal cord, through one of the many branches
of the nervous system. When this minute electrical current issuing from
the brain reaches the forearm, there, it causes muscle cells to contract,
which in turn pulls a tendon that causes your finger to move.
All these phenomena take place at practically the same time. There
is a flow of data from both the eyes and the finger back to the brain,
thanks to which the brain checks whether the movement is in line with
the command it gave. If the movement of the finger meets an obstacle
and is unable to do what is required of it, the brain can modify the situ-
ation by issuing new commands.
Gerald L. Schroeder cites one example of the supervision between
the muscles and the brain:
Muscle distribution within our bodies is filled with
cleverness. Hold your hand up and bend your fin-
gers. Notice that the muscles that allow you to
cup your hand by bending your fingers down
are not located in your fingers. Make a fist and
feel the inner, smooth side of your arm just be-
low the elbow. Feel
those muscles flex.
They are connected via
tendons to your fingers
and give the pull that
shapes your fist. By hav-
ing the muscles located on
the arm rather than at the
fingers, the fingers remain
slim enough to do fine work
such as holding a stick or typing