A person passes through this age, a weak infant who can not understand anything of this life except crying, and then entering childhood, which is one of the most beautiful stages of life and purity, in which the child begins to learn new things he did not know before, And then move to adolescence, which is one of the most difficult stages of human life in which he feels loss and dispersion between his childhood and his youth, and remains so until he settle in the youth, which begins to think seriously in his life and planning to build his future, to weaken his body after that He gets ill when he arrives Aging.
Each stage of the life of the human being undergoes major changes in his or her physique and physical structure. As the age progresses, various physiological changes occur in his body, growing and becoming more mature. In general, human growth depends on four important glands, whose tasks are to oversee and regulate the growth process The thyroid gland, the pituitary gland, the thymus, the sexual gland. When these glands work properly, the growth of the human body is intact. However, when there is a defect in its work, it will negatively affect the growth process and thus cause problems. Which are grown with the San while his age is the length.
The length of the human is defined as the vertical distance between the bottom of his feet up to the top of his head, and it is customary that the length is measured by the metric system, ie using the centimeter unit, usually the average height in males than in females.
The length of the human is uneven at all ages in his life. The infant is very tall, with an average length of about 70 cm, but when he reaches the age of 20, his height will be longer than three times that length to an average height of about 170 cm , But height does not continue to grow throughout the life of a person, as it stops at a certain age. Females stop growing at age 17. For males, their growth depends on their age at 19 years or more or less Two years at most for both parties – and after reaching the age of forty begins the length of the human body N shrink, so shrinks at a rate of 10 mm, due to drought in the cartilage in the joints and spine.