Question

Gigantism and dwarfism in humans basically depend on the quality and quantity of the food eaten during the early growing age.
(a)True
(b)False

Answer 1

Hint: Over secretion of growth hormone stimulates the abnormal growth of the body and low secretion of the same results in stunted growth. Abnormal hormone secretion is a genetic problem. Growth hormone is a protein hormone which stimulates the cells to grow and multiply. They also maintain their size once optimum growth is attained.

Complete answer:
Overproduction of growth hormone causes Gigantism and the Deficiency of growth hormone causes stunted growth or dwarfism. Abnormal hormone secretion is a genetic defect and nutrition has no role in their secretion. The growth hormone mainly acts on the skeleton and skeletal muscles. GH causes the cells to grow and multiply by increasing the rate of protein synthesis in them. They promote the breakdown of fats by causing cells to switch from oxidation of sugars to the oxidation of fats for energy. In this process, GH stimulates adipose cells to release fat and stimulates the other cells to break down the released fat molecules. They accelerate liver glycogenolysis and release glucose into the blood. This may cause diabetes mellitus.

Additional Information: -Their secretion is believed to be controlled by two regulating factors from the hypothalamus, namely the Growth hormone-releasing factor and the Growth hormone inhibiting factor.
-These two factors are antagonistic in action. GHRH stimulates the secretion of GH from the pituitary.
-The GHIF inhibits the release of GH.
So, the correct answer is 'False'.

Note: - The growth-promoting effects of GH probably result from the conversion of certain factors to growth-promoting substances, such as somatomedins and insulin-like growth factors.
-These are peptides, synthesized in the liver under the influence of GH. They are structurally and functionally similar to insulin.
-Their growth-promoting effects are much more potent than those of insulin.