Growth, puberty and adolescence (growth charts) Flashcards
What is the middle line called ?
Mean/median/50th centile
What does SD measure ?
Measure of variability
What is a Z-score ?
It is the standard deviation (SD) above or below the mean. A z score of 0 is the same as a 50th percentile,
If there are 100 people measured, how many are within 1 SD from the middle line and how many are within 2SD from the middle line ?
68 are within 1SD from the middle line and 95 are within 2SD from the middle line
- Appreciate in the pic that it shows essentially 1 SD corresponds to 68% of the results are within the this deviation from the middle line
- 2SD corresponds to 95% of the results lying within this deviation from the middle line
- 3SD corresponds to 98% of the results lying within this deviation from the middle line
How can you tell if a child is showing normal growth ?
- Their measurements are within the normal range compared with children of their age
- Their rate of growth is within the normal range compared with children of their age
How do you tell that a child is growing at a normal rate ?
Basically by plotting them on the graphs over the time period and they stay on the same centile line hence growing at a normal rate.
If the point plotted on the growth chart is exactly on the centile or within 1/4 of it what is this described as ?
The child being ‘on the X centile’
If the point plotted is not exactly on or within 1/4 of the centile what is it described as ?
It is described as being ‘between centile X and Y’
What is a centile space defined as ?
The distance between two centile lines
What is the average age for boys and girls to enter puberty ?
Girls - 11yrs old, boys 6 months after
Appreciate the cause for the Beginning of puberty in boys and girls
Puberty occurs when the secretion of gonadotrophin releasing hormone (GnRH) by the hypothalamus, which is largely but not entirely suppressed during childhood, increases so that pulsatile secretion of luteinizing hormone (LH) increases, resulting in sufficient sex steroid production to result in the secondary sexual development.
Describe the development of puberty in boys after it has been initiated
In boys LH stimulates the Leydig cells to produce testosterone which induces the features of secondary sexual development. Human chorionic gonadotrophin (hCG) has similar structure and action to LH. Follicle stimulating hormone (FSH) binds to receptors on the Sertoli cells, enhancing spermatogenesis.
Testosterone modulates LH secretion. Inhibin B produced by the Sertoli cells exerts a negative feedback effect on FSH secretion. Sex hormone-binding globulin (SHBG) levels fall so that free androgen levels rise.
Describe the development of puberty in girls after it has been initiated
In girls LH stimulates proliferation of follicular and thecal cells, and during the follicular phase of the menstrual cycle induces androgen secretion by theca cells. FSH induces proliferation of granulosa cells; increases expression of LH receptors on granulosa cells; enhances aromatase activity so that androstenedione is converted to oestradiol (E2); and increases progesterone production. E2 acts on FSH receptors on the granulosa cells to cause proliferation of the follicular cells in addition to inducing secondary sexual development. Inhibin B is produced by granulosa cells in small antral follicles, inhibin A by large antral follicles and by the corpus luteum. Inhibins may have a role in inhibiting FSH secretion and in dominant follicle selection. Ovulation results from interaction of LH, FSH and E2 on the developing primordial follicle (see below). SHBG levels decrease only slightly.
Define what is precicious puberty
True central precocious puberty (TCPP) is normal pubertal development occurring abnormally early: <8 years for girls, <9 years for boys.
More common in girls than boys
Define what is pubertal delay
Pubertal delay is the absence of secondary sexual development in a girl aged 13 or a boy aged 14 years.
More common in boys than girls
