Q.

Hypersecretion of growth hormone in adults does not cause further increase in height, because             [2017]

1 epiphyseal plates close after adolescence  
2 bones loose their sensitivity to growth hormone in adults  
3 muscle fibres do not grow in size after birth  
4 growth hormone becomes inactive in adults.  

Ans.

(1)

Epiphyseal plate is a hyaline cartilage plate in the metaphysis at each end of long bone. It is part of long bone where new bone growth takes place. In adults, elevated levels of GH results in acromegaly where no increase in height occurs because of ossified epiphyseal plate.