Apr 23, 2017
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What Do You Know? – Unravelling The Mysteries Of The Human Body!

Do you know… Why heartbeats make a noise… Which is the most difficult food to digest… Why pinpricks on the fingertips are more painful than on the buttocks… The secrets and mysteries of the human body never cease to fascinate. Here below, we unravel a few…

Can a small child recognize its mother by smell?

Since human babies are born in hospitals and clinics, it has been possible to make some very interesting observations on their reactions. For many years it was thought that these crying, wriggling, red-faced parcels needed only milk, warmth and cleanliness and, as a very minor consideration, an infrequent tickle under the chin from the mother. This was measured by the strict discipline of these institutions. Now, experiments based on commonsense are under way, in order to overturn the rigidity of the established rules.

It is now known that a new-born child recognizes his mother’s milk. If he is offered several teats impregnated with milk from various mothers, he will grope with his little mouth towards the one which has his mother’s smell and taste.

A baby also reacts to his mother’s voice. Whilst he is growing inside the womb, he hears her voice. But it sounds deeper in his warm, cosy world. After birth, he recognizes these sounds among all the others which now reach his tiny ear. For him they represent well-known, friendly signals in a strange world.

As for the mother’s smell, children are aware of it for a very long time after birth. Up to the age of two years, they can recognize their mother’s sweater from among others, practically every time. There are obviously odours which are so slight that adults appear not to notice them, but babies and children do.

We know that in herds consisting of hundreds of animals, mothers and young recognize each other. Why has it taken so long for humans to find out whether there are links between human mothers and babies based on taste, sound or smell – and whether this could be important for the balanced development of children? Maybe previously there were more urgent problems. Now, however, the field of research and observation is expanding, and, more importantly, experts in all areas are pooling their knowledge and working together.

[Read: Natural Height Increasing MethodsGrow Taller 4 Idiots]

Why does a child have to learn to walk on two feet?

It still seems curious that if a child is reared away from his natural surroundings, that is, far away from the company of people, he does not walk on two feet, but on all four like the animals around him. However, it is also true that the new-born child has a natural instinct for walking on two feet. Immediately after birth, doctors check a certain number of reflexes (involuntary actions), including the reflex for walking. When the baby is held so that his feet are on a firm surface, he straightens his legs as if to stand and lifts one leg as if to take a step. This is known as the ‘step reflex’.

These reflexes disappear shortly after birth as the nervous system matures and learned movements become possible.

Why do heartbeats make noise?

It is impossible to put your ear to your chest to listen to your own heart beating. And not everybody has a stethoscope to listen to his neighbour’s. However, films and documentaries have let you hear the very characteristic rhythmic beat, which modern composers have sometimes imitated in their music. It is the heart valves that produce the familiar double heart-beat sound, known to doctors as ‘lub’ and ‘dup’. The first sound which lasts for approximately one-tenth of a second, is dull and muffled; the second, which follows fairly closely, is shorter and sharper. These two sounds are followed by a relative silence (approximately half a second for a person at rest). Sometimes a third sound is heard, one-tenth of a second after the second sound.

Where do these sounds come from?

The first sound you hear, the one which says ‘lub’, is caused by the rapid closure of the valve between the auricles and the ventricles (auriculo-ventricular valves). This sound, rather like a door closing, is accompanied by a dull murmur, caused by the contraction of the ventricular muscles.

The second sound is caused by the closing of the arterial valves.

As for the third sound, this corresponds to the arrival of the blood being expelled forcefully from the auricles into the ventricles.

Do blood groups vary according to race?

Experts studying different human populations are very interested in the distribution of blood groups. For example, it has been noted that Amerindians (American Indians) are practically always blood group O. There are very few pure Amerindians with blood group A, and group B is conspicuous by its absence. Asiatics have far more members of group B than Europeans. Among Europeans, blood group A dominates.

As for other blood-grouping systems, they also show differences. When they are studied, they enable us to reconstruct or confirm the history and comings and goings of a population to or from a particular region or country.

Why do we sometimes get a stitch?

When we run without having done much training, we often get what is called a ‘stitch’, a sudden sharp pain which forces the runner to stop.

Running calls for great muscular effort. ‘Effort’ means ‘energy consumption’. When the muscles are working, they require more fuel (sugar, for example), and oxygen to burn up the fuel, than when they are at rest. Only the blood can transport what they require. Likewise, the blood also carries away the waste products resulting from this effort: lactic acid and carbon dioxide. The heart, therefor, increases its rhythm to circulate the blood more quickly. Breathing becomes more important, because this puts oxygen into the blood and removes carbon dioxide from the blood. The muscles used for breathing also undergo intense exercise, but they are not responsible for the sharp, painful ‘stitch’ in the left-hand side. What causes the pain when we run too quickly or for too long, is a contraction, or cramp, of the spleen.

What does the spleen do? Its main role is to make white corpuscles, called lymphocytes. But it is also involved with red corpuscles: it produces red corpuscles in a baby while it is still inside its mother’s womb, and in severe cases of anaemia; it also keeps reserves of these corpuscles in its small chambers, in case of need.

Running requires a larger amount of oxygen. The oxygen is transported by the red corpuscles. Therefore, the spleen comes into action. It releases the corpuscles from its reserves, by contracting. If these contractions occur very close together, they will cause cramp. A ‘stitch’ is therefore cramp in the spleen.

Is it true that our skin is renewed every seven years?

The skin is made up of hundreds of thousands of cells, arranged in layers. These layers are called the ‘dermis’ (the lower layer), and the ‘epidermis’ (upper layer). Between the dermis and the epidermis there is a layer which produces new cells, called the ‘growing layer’.  This growing layer provides all the cells for the upper layers. It is constantly renewing the cells on the surface, which die, flatten, cornify and flake off. No, we do not shed our skin like snakes. But, thanks to this growing layer, our skin is continuously being replaced.

However, as we get older, the cells are not replaced as quickly. The dermis is less rigid, and the epidermis sags on to the soft dermis. The muscles beneath the skin are not as efficient as they used to be. Wrinkles appear on the face, and, on other parts of body, the skin starts to sag and looks dry. These are normal signs of ageing.

Why are needle pricks on the fingertips more painful than those on the buttocks?

The deeper parts of our skin conceal sensory nerve cells that are sensitive to heat, cold, pressure and pain. All these tiny nerve cells send messages to the brain about the sensations they feel. Some of these are not as deep as others. They are particularly plentiful in the fingertips, the palms of the hands and the soles of the feet.

Now you can see why a small needle prick on the fingertip, which has a lot of nerve cells near the surface of the skin, hurts more than a needle prick on the buttock, which has far fewer nerve cells. If you are lucky, a needle can even go into the buttock without touching them!

For how long is it possible to stop breathing?

The muscles which control breathing can also obey commands which we give them voluntarily. And so, it is possible for us to hold our breath. But the strain soon begins to tell and the face becomes red. This is because the brain must receive oxygen at all costs, and the blood therefore flows towards the brain. Eventually, holding the breath becomes unbearable. There is a feeling of suffocation. The voluntary instruction not to breathe is withdrawn… and the relief is immediate.

A trained diver can remain underwater without breathing for two to three minutes. Beyond this, the need for air is so great that instructions from the nerves will bypass the free will. The only way that the body can escape the control exercised by free will is through loss of consciousness. When this happens, the autonomic nervous system suppresses the free will and starts to direct operations. This may result in a cure which is worse than the cause: water may be inhaled into the lungs, and drowning may result!

All mammals, including humans, take oxygen in lungfuls and share it out through smaller and smaller tubes so that it is within reach of every cell in the body. The feeling of urgency that comes upon us if we try to hold our breath for more than a couple of minutes stresses how vital is our body’s need for air.

Why must we be careful when going into cold water?

If you plunge a glass into very hot water and then into cold water, there is a very good chance that it will crack. Yet someone who takes great care with his glassware, does not hesitate to dive straight into cold water after sun-bathing for half an hour, or even longer. This really lacks common sense!

The human body is remarkably well-equipped to adapt to very varied temperatures, but we have to give it time to do so.

The body needs to maintain an internal temperature of 98.4 degree F. If you are very hot – for example, you have been sitting or lying in the sun for a long time – the body triggers off systems to fight this excess of heat. These cause perspiration and dilation of the blood vessels running beneath the skin. If you then wish to dive into the water to refresh yourself, you must not do it too suddenly. This is because in water, your body will no longer be fighting the heat, but the cold. To avoid cooling down, the circulation will speed up and the diameter of the blood vessels under the skin decrease.

This reversal of the body’s air-conditioning system cannot be carried out suddenly without shocks occurring. These can be dangerous. Hydrocution (a sudden failure of blood supply to the brain due to immersion in water) is the worst which can happen, and often, unfortunately, results in death.

You must, therefore, be sensible about going suddenly into cold water. Take the following precaution: when the water comes up to your ankles, moisten the nape of your neck and your abdomen and kidneys by splashing water on your body. If you feel the slightest discomfort, dizziness, pains in the chest or a lump in the throat, the wise thing is to get out of the water. Sit in the shade until you have calmed down, and be prepared to postpone your swim.

If you dive straight into the water, you will not feel the above warning signals which tell you that the body’s defence mechanism against the cold is not working properly.

Ignore people who, when you go into the water slowly, treat you like a baby. They are the foolish ones. It is necessary for you to be aware of what it can and cannot do.

Why are we dazzled when we go from the dark into the light?

If you go from a dark room into a brightly lit place, you almost feel your eyes squinting and smarting. You are dazzled, you cannot see shapes and your whole vision is drawn to the light. The reason is that the visual purple in the rods reacts with the light and becomes bleached. It is quickly restored – quickly, but not instantaneously. That is why normal vision is slow to recover after being dazzled. This can be disastrous when driving at night, and if a driver is blinded by headlights, he should slow down immediately, in order not to lose control of his vehicle. Attempts are being made to prevent dazzle, but some people are more sensitive to dazzle than others.

Why is the urine red when we have eaten beetroot?

Urine, the yellow fluid secreted by the kidneys and excreted through the bladder and urethra, is 96 per cent water and 4 per cent solid constituents, the most important being urea and uric acid.

The kidney is an organ which purifies the blood. In addition to keeping the blood in the best possible condition for the body, it also gets rid of any undesirable substances in the blood, as far as it is able. Coloured substances, such as those found in beetroot, are not at all necessary to the body, so they are eliminated by the kidneys and the colouring appears in the urine. Do not panic, therefore, if you have red urine after you have eaten beetroot. It is not blood, just the juice from the vegetable.

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