The lungs are an excellent example of a natural fractal organ. The volume of a pair of human lungs is only about 4-6 litres but the surface area of the same pair of lungs is between 50-100 square metres. Surface area to volume ratio in lungs is very high and is very useful. This is possible only because the structure of lungs is fractal. There are 11 orders of branching, from the trachea to alveoli at the tips of the branches. Fractal branching geometry provides an incredibly useful way to make a very large surface area extremely compact.
Every cell in the body must be close a blood vessel, say within about hundred microns to be able to receive oxygen and nutrients. The fractal branching network of blood vessels down to the width of a capillary, which is about eight microns in diameter makes it possible. The length of blood vessels in human body could be about 150, 000 kilo metres of blood vessels as there are about 250 capillaries /mm3 of body tissue and the average length of a capillary is about six hundred microns.
The human brain comprises approximately 100 billion neurons with about 100 trillion synapses or connections among these neurons and on an average each neuron may have to communicate with about thousand cells at a time. The axons reach out to make synaptic connections with the dendrites of other neurons. It is the fractal branching pattern of the neuron’s axons and dendrites that allows them to communicate with so many other cells.
Many scientists are trying to find applications for fractal geometry, from predicting stock market prices to making new discoveries in theoretical physics. Fractals have more and more applications in science such as in astronomy, computer science (fractal compression), fluid mechanics, telecommunications (fractal antenna) and medical science. Sometimes fractals describe the real world better than traditional mathematics and physics.