HUMAN HAIR - A BIOLOGICAL NECESSITY
Hair is a characteristic feature of mammals, commonly known as "Hairy quadrupeds" - a group of animals that mark the climax of evolution. Mammals are also the dominant animals in the world today, due partly to their ability to regulate body temperature in the face of variations in environmental temperature. This requires regulation of heat production and heat loss by the body. Hair plays an important role in regulating heat loss from the body. Impulses from the brain (hypothalamus) causes the hair to stand on ends, thereby enclosing an insulating layer of air just outside the skin. This layer reduces the loss of heat by radiation.
Man Lost Tail for Hair
Man marks the climax of evolution even among mammals, and has the most complex and highly developed brain, and the longest hair on head. This feature cannot be without reason. It cannot be a matter of mere chance or a mistake by nature, because if the tails has been lost the hair too could have been lost. On the contrary, human head-hair has increased manifold as compared to other mammals.
Body's Extended Surface Area
This dense and long growth of hair on the head shows that the body is trying to increase the surface area for some particular function. Such a trend to increase the surface area is seen in every system of the body, e.g. the highly coiled intestines with finger-like villi on their inner surfaces for absorption of digested food; alveoli in the lungs for exchange of O2 and CO2; glomerular capillaries in the form of bunch and coiled tubules in the kidneys where urine formation takes place. The circulatory and nervous systems show extensive branching to reach every nook and corner of the body. Even the surface of the human brain has maximum fissures (folds) corresponding to its increased abilities. The results that will be produced by decreasing the surface area of these points is easy for all to imagine!
Hair performs a variety of functions. Some are :-
Form an insulating coat on the body. Trap a layer of still air just outside the skin, and thereby reduce loss of heat by radiation. Absorb harmful radiations from the sun.
Keep out coarse dust particles, as in eyelashes, hair in the nasal chambers and ear canals.
Eyebrows prevent water or perspiration from falling into eyes, due to their particular direction.
Axillary and pubic hair lessen friction between limbs and body, and between limbs during locomotion.
Help Sweat Evaporation
Axillary hair provide large surface area for evaporation of sweat.
Beautify the body (otherwise why people do not shave off their hair from the head completely; bald men are desperate and would pay any price to get back hair on their heads).
Beard and moustaches are for differentiation of sex. Mostly males are decorated in nature, e.g. lion, peacock and other birds, deer, etc.
Protect from sun and rain.
Prevent water from entering into skin.
Attribute for Body's profile
Impart colour to body.
Vibrissae are sensory hair, tactile in nature and useful in dark burrows.
Defend the body in danger, by standing on their ends, thereby making the body look bigger.
Help to disguise by blending with the colour of the surroundings, to escape the watchful eyes of natural enemies.
Brain Keeps Account of Each Bit of Each Hair
Hair is erroneously considered lifeless because of lack of any visible connection with the brain. But, the brain is not controlling/communicating with our body through nerves alone. Hormones, which are chemical mediators also regulate various body functions. The immune system of the body fights infection with the help of coordinated action of cells, which have no visible connection with each other, or with the brain. So, presence or absence of nerves alone cannot determine the connection of a particular part of the body with the brain.
Hair Respond to Status of Health
If the hair was really dead to the brain, how then does it come to know that it has been cut, and respond by growing it again to the specific length? Once the specific length has been attained, further lengthening ceases. Thus, undoubtedly the brain is well aware of the condition of the hair, cut or uncut, even upto its tip! This is a sure sign of life. Also, the hair, like any other living organ of the body, responds to ageing, in their length, thickness of growth and greying. The condition of the health of a person is also reflected in the hair, its lustre, shine, etc.
Hair Has No Sensation, Neither Has Brain
Lack of sensation in hair, is no indication of its being dead, for, even the brain shows no such sensation. There is also a phylum (Porifera), the animals of which do not possess a nervous system at all. A blow to any part of their body produces no response whatsoever. Do we call these animals dead? Most plants do not show any sensation either.
Brain Has No sensation but Works, so Do Hair
Further, a part of that we call "dead" may be without sensation but definitely not without function. Rather, its function is as important as any living part of the body, if not more. For example:
What would be the fate of an egg without the shell? What would be the condition of the body's living cells without the covering of the dead cells, i.e. upper layers of skin? How can teeth perform their function without enamel? What life would a bird lead without feathers? How would many freshwater animals overcome unfavourable conditions and not become extinct without cysts? How would plants disperse and reproduce without formation of seeds? Actually, different parts of the body or different cells cannot be categorised as useful/not useful. Each is only specially modified to perform different function for the benefit of the same individual. What the cells of a kidney can do, the cells of pancreas cannot. That does not mean that the former are more important than the latter, or vice versa.
HAIR VS. NAILS
It is often argued that hair and nails are similar, and a question frequently asked: "If we should not cut our hair, then why do we cut our nails?" But even a superficial study of the two shows them to be extremely different from each other. Whereas the hair grows from a tubular pit, the hair follicle, formed by sinking in of the most actively dividing layer of the skin, i.e., stratum germinativum, into the lower dermis, the nails are only modifications of the upper dead layers of the skin, i.e. stratum corneum. Further, the base of every follicle bulges out forming an inverted cup, which receives blood capillaries for nourishment and nerve fibres that make the hair sensitive to contact. An oil gland, known as sebaceous gland, opens into every hair follicle, the secretion of which lubricates the hair. A muscle is also attached to the base of every hair for bringing about movement. Pigments are added to the shaft of the hair as it grows. None of these features is associated with nails.
Structurally also hair is extremely strong, and resists breaking due to its elasticity and flexibility. Hair is as strong as steel, if we compare the two of the same diameter. Nails, on the other hand, are very brittle and rigid, breaking off easily. Hair number in thousands, thereby increasing the surface area, as if to meet a specific requirement. Nails number only twenty.
The difference between the two do not end with the structural features. Even the body's response towards the two is totally different. Our body, throughout life, tries to maintain a particular length of hair, and if cut anywhere along the length, responds by growing them again to the specific length. It clearly indicates the link of the body with the hair all along its length.
The body shows no such response to the nails, which grow from birth to death at the same rate, irrespective of whether cut or not. As has been mentioned earlier, even the shafts of hair, like any other living organ of the body, respond to ageing (in their length, density of growth, greying, etc.) and condition of health is reflected in the person's hair (in their lustre, shine, etc.), whereas from the dead part of the nail, one can infer no such thing.
Practically also, hair do not interfere in any daily activity, whereas it is impossible to function at all with long nails. And even if not cut, nails generally fall off of their own easily; rather it takes great effort to maintain them, even upto a short length. In contrast to the long list of the functions of hair, only one function can be attributed to nails - that is, protection of the tips of digits.
To sum up, if there is anything on the head that can be compared with nails, it is dandruff!
It is also argued that hair have been lost from the body in man, because the body is kept covered. If that be the case, then the axillary and the pubic hair should have been the first to go. Also, the hair on the face, neck and hands should have remained.
Nature knows best what to discard or retain. Whatever is retained is not without purpose. If we are unable to explain something, it does not mean it has no significance. We must look for an explanation, rather than deny the role or existence of something we do not see.
There are sound frequencies we do not hear; light waves, that make everything visible, we do not see; odours that we do not smell; there are animals that do not see as many colours as we do; some things we can neither see nor deny, such as emotions, the bond between mother and child, force of gravity, etc. So, if there are things we do not see, or hear, or smell, it does not imply their absence. Just as an ant cannot apprehend the size and shape of an elephant, life and its processes are beyond human apprehension in the present state of knowledge. Our vast Solar system, which is beyond reach even today, is just a speck in the universe! Even our smallness is beyond our apprehension!
Hair is a gift from God, not a burden. Guru Gobind Singh, in his infinite wisdom, commanded us to respect it and to refrain from tampering with it. This is the visible token of his affection for us, as well as our faith in him. If we have faith in our Guru who was in communion with God, how can we do anything but follow his advice?
As Prof. Puran Singh says: "Let us sing in gratitude 'The Song of the Sikh'":
"Ah! Well, let my hair grow long; .... I cannot forget the knot He tied on my head; It is sacred, it is his mark of remembrance. The Master has bathed me in the light of suns not yet seen; There is eternity bound in this tender fragile knot. I touch the sky when I touch my hair, and a thousand stars twinkle through the night."