One of the characteristics of living being is growing. By growing, all living organisms improve their composition and functions. The most important factors that cause growth are hereditary and can be found in the embryo of a living being.
Both, human beings and animals go through several stages of development. These are: embryonic stage (in the womb), infant period, then childhood, adolescence, adulthood and finally, old age.
Some creatures hardly have early childhood. Some birds, for example, can fly as soon as they are hatched. Guinea pig is able to take care of itself, even on the third day after the arrival on the world. A human being is fully grown only when it gets around twenty years old!
From the first moment, the infant has all those nerve cells that will have throughout whole life: the brain and peripherals. The development of links between these nerve cells allows the child to control its movements, to learn and acts as a social being.
All human beings grow in a similar way, but there are also some important differences between children of different sexes. Boys and girls undergo the same path, but in different ways and at different speeds.
During the first few weeks after birth, the body is growing much faster than later in the life. Already at the end of the first year of life growing slows down, and throughout childhood it is quite moderate. At the end of the childhood, growth rate begins to accelerate. This period usually occurs in girls between the eleventh and thirteenth year of life, and boys between twelfth and fourteenth year of life. For a while they grow until they reach the highest possible growth rate. Then the growth rate begins to decline, until the moment when growth stops completely.
Increasing height and weight usually doesn’t happen at the same time. At the first place is growing in height, and then gaining weight. Many kids go through so called “chubby” period, between eleventh and twelfth year of life. Then the child begins to rise sharply and “chubby” look is lost.
Why do we stop growing?
Newborns are average 48-50 cm long. Over the next twenty years the length of the body is increased over three times, and for a woman is about 160 cm and for the men about 175 cm. However, a human being does not cease to grow. It actually continues to grow, even after twenty- fifth year, and it reaches its highest altitude at the age of 35 or 40 years old.
What happens after these years? The man stops growing and begins to “shrink”. Everyone decreases in height after the age of forty, approximately 1 cm every ten years. Reason for this reduction is the gradual loss of water from the cartilage in the joints of the spinal column.
Do you know that we are every morning higher than the previous evening, and that is the day we reduce in height?
The growth rate varies during different seasons. Kids grow faster in summer than in winter. Better food, healthier way of life and a variety of other circumstances are the reasons that make today generation, on average, higher than the earlier.
Height growth depends on the work of the four glands: thyroid, pituitary, thymus and gonads. When these glands are working normally and when there is an appropriate balance between their activities, growth is normal.
Why do we stop growing? What is it that stops the growth?
The pituitary gland stimulates bone growth. If the gland functions excessively, hands and feet grow too, and the hands and feet of that person become very large. If the pituitary works insufficiently, the person remains small – a shrimp.
A child is born with a large thymus, which grows during childhood. When the child turns thirteen or fourteen years, a fat begins to replace the thymus. With the end of puberty, it is in most people completely lost. In its place remains adipose tissue. Such a reduction in thymus falls at a time when sex glands begin to work. A person who sexually matures, usually in twenty- second year of life, it stops to grow.
Sometimes the gonads develop too quickly, and thymus growth is slowing down too soon. In such a case the person does not reach an average height. Since the legs grow later, but more than other parts of the body, in this early stage of development legs are short, and people who are prematurely developed often look stocky. Such is, for example, Napoleon.
If the gonads begin to develop too late, the thymus continues to work and such people reach their superior height.