Growth and Puberty: Normal Growth

Question 1

How many phases are there for normal human growth and what are they?

Answer 1

4: fetal, infantile, childhood, pubertal growth spurt

Question 2

Which is the fastest period of growth?

Answer 2

Fetal period

Accounts for 30% of eventual height

Question 3

What is size at birth determined by?

Answer 3

Size of mother
Placental nutrient supply
- which in turn modulate fetal growth factors (IGF2, human placental lactogen and insulin)

Question 4

Optimal placental nutrient supply is dependent on…

Answer 4

Adequate maternal diet

Question 5

Is size at birth largely independent or dependent on father’s height and GH?

Answer 5

Independent

Question 6

Does low birth weight increase or decrease the risk of childhood obesity?

Answer 6

Increase

Question 7

Growth during infancy to around 18 months is largely dependent on…

Answer 7

Adequate nutrition
Good health
Normal thyroid function

Question 8

Describe the growth rate in the infantile phase

Answer 8

Rapid but decelerating rate

Accounts for 15% of eventual height

Question 9

By the end of the infantile phase, children have changed from their fetal length largely determined by uterine environment, to their…

Answer 9

Genetically determined height

Question 10

An inadequate rate of weight gain during infantile phase is called what?

Answer 10

Faltering growth

Question 11

Describe growth in the childhood phase

Answer 11

Slow, steady but prolonged period of growth that contributes 40% of final height

Question 12

What is the main determinant of the child’s rate of growth during the childhood phase?

Answer 12

Pituitary GH secretion acting to produce IGF1 at the epiphyses

• thyroid hormone, vit D and steroids also affect cartilage cell division and bone formation
• profound, chronic unhappiness can decrease GH secretion = psychosocial short stature

Question 13

Describe the pubertal growth spurt

Answer 13

Sex hormones mainly testosterone and oestradiol cause the back to lengthen and boost GH secretion
Adds 15% to final height
The sex hormones cause fusion of epiphyseal growth plates and cessation of growth

Question 14

If puberty is early, how can this affect growth (especially in girls)?

Answer 14

The final height is reduced due to early fusion of the epiphyses

Question 15

The fetal and infant growth are mainly dependent on..

Answer 15

Adequate nutrition

Question 16

The childhood and pubertal phase are dependent on…

Answer 16

General health
GH
Other hormones

Question 17

Why are adult males taller than adult females?

Answer 17

They have a longer childhood growth phase, their peak height velocity is higher and their growth ceases later