Search results
Results From The WOW.Com Content Network
Newborns typically lose 7–10% of their birth weight in the first few days, but they usually regain it within two weeks. [ 17 ] During the first month, infants grow about 1 to 1.5 inches (2.5 to 3.8 cm) and gain weight at a rate of about 1 ounce (28 g) per day.
The speed of physical growth is rapid in the months after birth, then slows, so birth weight is doubled in the first four months, tripled by 1 year, but not quadrupled until 2 years. [85] Growth then proceeds at a slow rate until a period of rapid growth occurs shortly before puberty (between about 9 and 15 years of age). [86]
Due to natural variation, individuals pass through the Tanner stages at different rates, depending in particular on the timing of puberty.Among researchers who study puberty, the Tanner scale is commonly considered the "gold standard" for assessing pubertal status when it is conducted by a trained medical examiner. [5]
Growth charts can also be compiled with a portion of the population deemed to have been raised in more or less ideal environments, such as nutrition that conforms to pediatric guidelines, and no maternal smoking. Charts from these sources end up with slightly taller but thinner averages. [1] Growth curve of a girl, compared to the 2006 WHO curves
Linear growth is a complex process regulated by the growth hormone (GH) – insulin-like growth factor-1 axis, the thyroxine/triiodothyronine axis, androgens, estrogens, vitamin D, glucocorticoids and possibly leptin. [25] GH is secreted by the anterior pituitary gland in response to hypothalamic, pituitary and circulating factors.
IGF1 (insulin-like growth factor 1) rises substantially during puberty in response to rising levels of growth hormone and may be the principal mediator of the pubertal growth spurt. Leptin is a protein hormone produced by adipose tissue. Its primary target organ is the hypothalamus.
In females, the pubertal growth spurt arise early in puberty due to the direct stimulation of sex steroids and indirectly by the growth hormone-insulin-like growth factor (GH-IGF) axis. [17] Ovulation and follicular functions are stimulated by the gonadotropins released by the hypothalamic-pituitary-gonadal axis' action. [ 11 ]
Infant cognitive development is the first stage of human cognitive development, in the youngest children. The academic field of infant cognitive development studies of how psychological processes involved in thinking and knowing develop in young children. [ 1 ]