Do You Know Why Heartbeats Make A Noise?

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.

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.