Page 84 - The Miracle of Electricity in the Body

82 THE MIRACLE OF ELECTRICITY IN THE BODY

than a million cells. Exceedingly complex biochemical processes take
place in every one of them. Heart cells are nourished by sugar molecules
and oxygen coming directly from the lungs. Every cell has its own
pumps and channels and is joined to its neighbors by connective tissue. 51
Every long, thin cell has a cell membrane that divides the cell from
the environment outside and fiber-like proteins that are able to contract.
Proteins embedded in the membrane carry important signals or sub-
stances from one side of the membrane to the other. In terms of electrical
charge, this polarizes the cell, generating a voltage difference between
the inside and the outside of the cell. This difference, known as mem-
brane potential, enables certain proteins in the cell membrane, known as
ion channels, to function like gates. When they are opened, ions flow in.
As a result of complex interactions of ion pumps and channels, a
heart cell contracts thanks to the electrical and chemical differences oc-
curring along the length of its cell membrane. Consider a cell in the heart
ventricle as an example. At a state of rest, the membrane potential in any
cell is more negatively charged than its external environment. However,
the electrical stimulus arriving from the neighboring cell rapidly alters
everything. This differential suddenly increases, and the sodium chan-
nels quickly open up. In this way, sodium ions (Na+) rapidly enter the
cell, triggering the opening of the calcium channels.
When calcium ions (Ca+2) collect around the cell proteins, these
contract. At this point, the sodium and calcium channels close and the
ion pumps move the ions outside the cell, causing it to return to its orig-
inal state. In a healthy heart cell, this transition takes place in less than a
second.
The events described here are in fact only a very general account of
the true state of affairs, which is much more complex in its details. The
heartbeat, which requires so many conditions to be met and work to-
gether flawlessly, is one of the countless examples introducing us to the
knowledge of our Lord.
In one verse of the Qur’an the following is revealed:

My Lord encompasses all things in His knowledge, so will you not
pay heed? (Surat al-An‘am, 80)