The growth of a human is largely due to the proliferation of body cells. By dividing the cells more and more of these cells arise. Until the human is fully grown, this process is repeated again and again.
On average, humans grow up to their twenty-fifth year. The growth is controlled by the human growth hormone somatotropin, which is passed through the pituitary gland.
Growth is faster during the night, as the concentration of growth hormone is highest during this time. Children grow at different speeds and there are a few factors that determine the average size.
When the baby is born, the head still accounts for about a quarter of the body length. In the course of growth this changes. Children and adolescents can be divided into three phases of growth:
In the first phase, the time from birth to the third year, the children grow fastest. During this time you can gain up to 45cm in height. The growth rate continuously decreases.
From the age of three one speaks of the second phase of growth. This lasts until shortly before the onset of puberty. In this phase, the children grow between five and six inches per year.
In the third and final growth phase, which begins at puberty, people gain between seven to nine inches in height each year. The growth rate reaches its peak in this growth phase. Adolescents grow between 17 and 24 centimeters, with girls tending to grow less than boys.
On average, girls grow a little faster and are initially taller than boys. But this balances out again in the course of puberty. With the end of puberty comes to a standstill. The height of adulthood is reached.
Hormones play the biggest role in growth. They are messenger substances and pass on the information between the cells, the tissue and the organs in the body. Only with sufficient hormone levels of the hormone somatotropin can full adult size be achieved. This hormone regulates almost all growth processes that are important. It also promotes the conversion of body fat into energy, which regulate blood sugar, and affect the immune system.
Not only the hormone somatotropin plays an important role in the growth process. Also heredity and the way of life of humans are crucial. For example, if the parents are small, the likelihood that the child will not reach excessive body length is high. Already in the time of fertilization is thus approximately determined how big the man will become.
It is also crucial which way of life man pursues during growth. In case of permanent malnutrition or a poor composition of the food (that means, too few proteins or vitamins are consumed) the growth process can be significantly impaired.
Long-lasting illnesses or disturbances in the function of our glands can influence the growth in the negative. If there is a lack of growth hormone, the sufferer suffers from dwarfism.
In dwarfism, the anterior lobe of the pituitary gland did not work well enough and the child remains in physical development. The whole body gives the appearance of an underdeveloped person.
If the thyroid gland does not release enough hormones after birth, it can not only affect the growth of the length. These children suffer from myxedematous dwarfism, which can also affect their cognitive abilities. By supplying the thyroid hormone this defect can be corrected to a large extent.
The opposite of the dwarfism is the high growth. In this case, the anterior pituitary works too fast during development. This peculiarity of growth can only be felt in the later years of life. In this phase, the growth of the bones is already complete. An increase in length of the bones is then not possible, but the bones can then be larger at the ends and there is a peak magnification (acromegaly). In this disease, fingers and hands, as well as toes and feet, nose, lips and chin are enlarged.
Larger people are more likely to struggle with back problems. The body has a heavy burden to bear, this manifests in the form of back pain. But even small people have to fight in everyday life. Not only do small people on average classify their quality of life as lower, they are also more likely to suffer from depression, anxiety, and discomfort.
According to a study, the size of people's satisfaction increases. However, the concrete cause for this is less to be found in the biology of human beings than in social values, which defines a certain size as attractive.
In our age, thanks to modern medical advances, it is possible to determine the expected body size. An exact method is the determination of bone age. Through this investigation, a conclusion can be drawn on the expected growth.
Also, a growth curve can be created in a somatogram. The body develops in the same percentile of the body length, which can predict how the future development will be approximately.