Fundamental Mechanisms in Human Growth and Puberty Flashcards
What are the requirements for normal human growth?
Absence of chronic disease, emotional stability, nutrition, normal hormone and growth factor actions and healthy growth plates
Name the 3 phases of normal linear growth
Infancy, childhood and puberty
Outline the infancy phase of linear growth
Grow at greatest rate, and dependent on nutrition largely
Outline the childhood phase of linear growth
Grow at medium, constant rate and is dependent on thw GH-IGF axis
Outline the pubertal phase of linear growth
Grow at fast peak rate and this is dependent on sex steroids and increased growth hormone production
Why is height and weight measured?
Can identify short stature disorders e.g. growth hormone deficiency or Turner syndrom
What is meant by the 91st centile?
That 91% of people are below that line
What could be the cause of proportionate short stature?
Turner syndrome, hypothyroidism, GI disease, psychosocial factors
What could be the cause of disproportional short stature?
Skeletal dysplasia including rickets
What may advanced bone age suggest?
A tall stature will result and could be due to central precocious puberty
What may delayed bone age suggest?
Growth failure that is secondary to paediatric Cushing’s disease, perhaps
Define what is meant by ‘short stature’
Length/height less than 2SDs of the mean for the age and sex of the appropriate reference population
How is the onset of puberty defined by Tanner?
Girls: Stage B2 ( budding of breast)
Boys: Stage G2 (testis volume > 3mL)
What is the mean age of puberty onset?
Girls: 11 years
Boys: 12 years
What genetic and environmental influences may affect the timing of female puberty?
Intrauterine growth, fat mass (leptin), endocrine disrupting chemicals, nutrition
