Electrical design in the human body
In the last century, our society’s dependence on electricity and all the devices associated with it has grown phenomenally. How many of us can really imagine what it would be like without electricity? Yet, electricity and devices which harness it have been around since the beginning of creation!
Electricity itself can be defined as the movement or current of small charged particles, usually electrons. Some substances, such as metals and various types of liquids, allow the movement of (or conduct) charged particles better than others. The harnessing of electricity has enabled us to develop devices which cause electrical energy to be changed into some other form of energy—e.g. heat (cooking), light (electric bulbs), motion (electric motors).
Man was not the first to harness electricity and put it to work. When we look at the human body, for example, especially the nervous system, we should conclude that the designer of the human body must have had an intricate knowledge of electronics and must have known how to harness electrical energy to change it into other forms of energy. When we consider the scale of the operation (i.e. at the atomic and microscopic levels), we can only wonder at God’s profound wisdom in creation.
The nervous system is composed of two parts: the central nervous system, which is the control centre comprising the brain and the spinal cord, and the peripheral nervous system, which consists of nerves connecting other parts of the body to the control centre. Via a combination of electrical and chemical processes, the nervous system is used to control the functioning of the entire human body.
Scientists inherently acknowledge that the nervous system is built according to an electrical design. The scientific literature describing the nervous system is replete with references to electrical theory and electrical devices that man uses today. Such references include technical words like batteries, transducers, motors, pumps, calculators, transmitters, electrochemical potential, circuitry, binary system, current, resistance, voltage, capacitance, charge. The difficulty of describing the nervous system without resorting to such language implies the Creator’s understanding prior to man’s electrical inventions.
The basic building block of the nervous system is the nerve cell, called a neuron. The brain itself consists primarily of neurons. Under a microscope a neuron looks like an octopus with many tentacles. A neuron can transmit an electrical impulse to the next neuron (see How do our nerves transmit information?). The network of electrical impulses enables us to receive information from the physical world and then send it to our brains, and vice versa. Without the neuron circuits our bodies would completely shut down, like turning off the power supply to a city.
One textbook author states, concerning the nervous system, ‘We speak of it as the most local circuit, or a microcircuit. It is very common for a particular type of microcircuit to be repeated throughout a layer or a given cell type, thus acting as a module for a specific type of information processing.’1 [Emphasis added.]
Information from the physical world to our brain is relayed via our five senses using electrical devices which change one form of energy into electrical energy. Our bodies have sensory receptor cells because there are different types of physical stimuli to be changed into electrical signals. For example, a different type of receptor cell is required for hearing stimuli than for smell stimuli.
The neuron may be likened to a switch which is turned either on or off according to the right conditions. ‘Under normal body conditions, the frequency of [electrical pulse] transmission may range between 10 and 500 impulses per second.’2 The impulse is not generated unless the neuron has been given a strong enough stimulus. It is hard to imagine the complex integration of electrical signals without realizing the Creator’s power and wisdom.
The individual neuron is only a small component in the interconnected circuitry of the nervous system. Information scientist Dr Werner Gitt says, ‘If it were possible to describe [the nervous system] as a circuit diagram, [with each neuron] represented by a single pinhead, such a circuit diagram would require an area of several square kilometres … [it would be] several hundred times more complex than the entire global telephone network.’3
To gain a true comprehension of the complexity of this circuitry, we must understand that co-ordination between neurons is essential. The computations required for such co-ordination are enormous. ‘There may be from ten trillion to one hundred trillion synapses [i.e. connections between neurons] in the brain, and each one operates as a tiny calculator that tallies signals arriving as electrical pulses.’4 [Emphasis added.] Thus, messages to and from the brain are relayed, moving from one neuron to another.
It is difficult to understand how anyone can believe that the nervous system, particularly the brain, could have been produced by evolutionary randomness and selection. We have barely touched on some of the electrical design present in the rest of the body.
The truth is that scientists are always discovering more about its workings, since its complexity, which far surpasses anything produced by man, is nothing short of a miracle. Truly we can say with David, ‘I will praise You, for I am fearfully and wonderfully made; Your works are marvellous and my soul knows it very well’ (Psalm 139:14).
How do our nerves transmit information?
A nerve fibre is actually an extension of a single nerve cell.
The inside and outside of most of our cells are bathed with fluid containing positively and negatively charged ions (e.g. sodium Na+; potassium K+; chloride Cl_). Using complex biological ‘pumps’, the cell’s machinery is able to transport positively charged ions through the (semi) permeable membrane, with the end result being that there is a slight excess of negatively charged ones inside. This means there will be an electric potential across the membrane, so that the inside and outside are like the positive and negative poles on a battery, i.e. it is polarized (Fig. 1).
If something causes the membrane to suddenly become more permeable at one spot, the resulting flow of positive ions back into the cell causes the charge differences to cancel out at this point—i.e. , the membrane will become depolarized there (Fig. 2).
This depolarization then spreads sideways, like a wave, along the cell wall, i.e. along the nerve fibre. The message in our nerve fibres is not transmitted by an electric current as such, but by a wave of depolarization (Fig. 3). The cell’s biological pumps restore the electric charge to the membrane behind the path of the wave.
A number of things—mechanical or electrical stimuli, or chemical effects—can cause this temporary increase in permeability. Where one nerve fibre A makes contact with another B at what is called a synapse, the arriving wave causes the release of special transmitter chemicals from tiny containers. These chemicals cause depolarization in B at that contact point, so starting a new wave of depolarization going in the same direction. Once released, the transmitter chemicals have to be broken down almost instantly, otherwise B would stay depolarized, and unable to build up charge ready for the next ‘firing’.
Organophosphorus insecticides (e.g. malathion) work by preventing this breakdown, thus the insect’s nerve cells cease to function properly. Because our nerve fibres use the same transmitter chemicals, malathion is poisonous to humans if exposed to enough of it.
This whole cycle of charge, discharge, chemical release, breakdown, and remanufacture, can happen several hundred times per second. Even with this very simplified description, it is clearly an astonishing process. The information to plan and make all this is stored in code on our DNA, the material of heredity. We really are fearfully and wonderfully made!
References and notes
- Shepherd, G.M., Neurobiology, Oxford University Press, London, p. 577, 1983. Return to text.
- Tortora, G.J. and Anagnostakos, N.P., Principles of Anatomy and Physiology, Harper & Row, New York, p. 290, 1981. Return to text.
- Gitt, W., The Wonder of Man, CLV Publishing, Germany, p. 82, 1999. Return to text.
- Restak, R.M., The Brain, Bantam Books, New York, pp. 34–35, 1984. Return to text.