Dwarfisam is caused by all except
Dwarfism is caused by all except
a. Thyroxin deficiency
b. Castration before puberty
c. GH deficiency
d. GH receptor abnormality
e. Female with XO karyotype.
Answer
b
. Castration before puberty
Discussion
Dwarfism
dwarfisam is condition in which people are abnormally short
Physiology of growth
Growth of human is controlled by following hormone
Grorth hormone
Somatomedins
Thyroid hormones
Androgens estrogen,
Glucocorticoid
Insulin
And growth is affected by
Genetic factors
Nutrition
In humans there are
two periods of rapid growth, the first in infancy and the second in late puberty just before growth stop. Second rapid growth is controlled by growth hormone, androgen and estrogen. Subsequently growth
is stopped due to closure if the ephiphysis in response to
estrogen.
Before closure of
epiphysis , growth is stimulated by growth hormone and excess of growth hormone cause gigandisam . After closure of epiphyses , excess of growth hormone causes acromegaly.Reduction of growth hormone before closure of epiphysis causes short stature ( d
warfism
).if men are castrated before puberty they bocme tall because their estrogen production is decreased and their epiphyses remain open, allowing some growth to continue past the normal age of puberty.
Causes for Dwarfism
1. Endocrine cause
GHRDdeficiency
GH deficiency
IGF1 deficiency
Unresponsive GH receptors
Hypothyroidism (cretinism)
2.Constitutional delayed growth
3. Achondroplasia
4.Precocious puberty ( due to early closure of epipysis in respose to oestorgen )
5.Gonadal dysgenesis (XO chromosomal pattern instead of an XX or XY pattern)
Mnemonic to remember cause for short stature
1.
ABCDE
Labels:
ENDOCRINE
,
Endocrine MCQs
,
Physiology MCQ