Ques. 1NEET 2017
Hypersecretion of growth hormone in adults does not cause further increase in height, because
- epiphyseal plates close after adolescence
- bones lose their sensitivity to growth hormone in adults
- muscle fibres do not grow in size after birth
- growth hormone becomes inactive in adults.
Answer
(1) epiphyseal plates close after adolescence
Solution
Growth in height occurs at the epiphyseal (growth) plates of long bones. These plates ossify and close after adolescence ⇒ no further increase in length of bones is possible.
As per NCERT, excess secretion of GH in adults, especially in middle age, therefore results in acromegaly (severe disfigurement, especially of the face) and not in increased height.
Answer: (1)