The growth is the increase in the size and body weight developing organism.
The growth of a multicellular organism is due to the increase in the number of separate components of its cells, their size, and also the total mass of the intercellular substance. Newborn animals, as a rule, differ sharply from the adult forms not only in size but also in quality, in line with the growth process must be considered in combination with other phenomena, accompanying the development of the organism during ontogenesis (see). The growth rate decreases with age. In addition, the rate of growth of individual organs and body parts of animals and humans is also uneven, and the proportions of the body during the life of the change that is the result of a complex interaction of factors that govern the formation of a living organism. In process of growth of change of physico-chemical properties of the body. Percentage of water in the growth of the progressive decrease in the embryonic period in a person with 97%to 75%, by months of age to 70%, and in adults water content is already 65%. The content of fat, protein and salts, on the contrary, increases.
Coordination of the process of growth in person the exclusive role played by the activity of the Central nervous system and endocrine glands. For example, the removal of the thyroid gland slowing growth. Similar phenomena occur in children with insufficient thyroid - congenital underdevelopment it causes a delay in physical and mental development. More distinctly impact on the growth of the pituitary gland.
The growth process in developing hereditary inclinations and manifested a number of properties required for further individual life. Their appearance depends on the specific conditions of the growth of the body. One of the conditions for successful growth is good nutrition. Prolonged fasting or insufficient in qualitative or quantitative terms, the power leads to the growth inhibition. Especially adversely affects the growth of the lack of food proteins, containing essential amino acids (e.g. lysine, tryptophan, tyrosine, phenyl-alanine), especially because some of the amino acids are essential for a growing organism (phenylalanine, tyrosine, cystine), as well as vitamins, mineral salts and some other nutrients.
The growth may have adverse impact of the disease, which develops dystrophy (congenital heart disease, encephalopathy, endocrine disorders), as well as hereditary diseases with severe metabolic disorders (cystic fibrosis, celiac disease, exudative enteropathy).
The intensity of the growth of the body length varies throughout the year and is the highest in the spring and early summer, the minimum growth rate - late summer and early autumn.
There are progressive, stable and regressive stage of growth. The first one covers the period from birth to 20-21 years for women and up to 25-30 years for males. Stage of stabilization of growth lasts for about 50 years, followed by a slow reduction (regressive stage) due to the curvature of the spine and flattening of intervertebral disks.
Body length, full-term newborn ranges from 48 to 52 cm (the average growth for boys 51 see, for girls - 50 cm). During the first days of life the body length of the child is decreasing, as is aligned cranial deformation resulting from the act of birth. Further increase of body length in children exposed to a wide individual variations in different periods of childhood is uneven. The most intensive growth in the first years of life. So, the length of the body for the 1st year of life increases by 20-25 cm, on the 2nd year increase is 10 cm, on the 3rd - 8th see the Original length of the body of a newborn doubled to 4 and triples to 14-15 years. In the period of puberty activity growth increases again.

Table of average height of children from 1 year to 15 years

Age, g Height, cm

Approximately the average child's growth over the year can be determined by the formula: X = 75 +5n, where X is the length of the body of the child in cm, n - its age in years 5 - growth rate for one year, 75 - growth year-old child (see table).
To characterize the physical development should assess the proportions of a body of the child as a separate body parts are growing unevenly: for example, for the entire period of growth leg length is increased by about 5 times, length of a hand - 4 times, in the body - in 3 times, and height of head - only 2 times.
Head circumference newborn 34-35 cm, chest circumference 32-34 see their Sizes are aligned to 2-3 months. After a year of chest circumference exceeds the head circumference of approximately as many centimeters, how old child.
As a result of uneven growth head, torso, limbs is offset from the middle point of the body length. In full-term newborn this point is the belly button, then down below, at the age of 6 years it is located between the navel and the symphysis, and an adult - at the symphysis.
In many countries of Europe and Russia there is a trend of increase in the intensity of growth, and earlier age and gender differentiation children - the so-called phenomenon of the acceleration (see). As a result of this simple averages of growth be more.