Question

Cretinism is produced when one of the following is deficient
(a) Adrenaline
(b) Growth hormone
(c) Parathormone
(d) Thyroxine

Answer 1

Hint: Cretinism is produced from the largest endocrine gland that is richly supplied with blood vessels. It is characterized by stunted body growth and development. It is a congenital disorder i.e present since birth.

Complete answer:
Abnormalities of thyroid function are among the most common disorders. The abnormalities may be due to excessive or deficient production of the thyroid hormone. Hypothyroidism reflects the disorder with deficient secretion while hyperthyroidism reflects the hyper- or excessive secretion. Cretinism develops when a person has hypothyroidism or low levels of thyroxine which is the result of deficiency of iron or its low levels since birth. As normal thyroid levels are essential for normal growth and central nervous development, its sub-optimal leads to dwarfism and mental retardation in infants. Some symptoms of Cretinism are lower body temperature and blood pressure, slow heartbeat, pot-belly, protruding chest, and retarded sexual development.

Additional Information: The thyroid gland develops from the endoderm - one of the three germ layers in an embryo. It is located in the neck, precisely to either side of the larynx. The lobes of the thyroid contain follicular cells and parafollicular cells that synthesize thyroxine and calcitonin respectively.
Thyroxine or tetraiodothyronine is the principal thyroid hormone. Some of its functions are:
-They are principally required to maintain one’s basal metabolic rate.
-By stimulating protein synthesis, they promote growth and development.
-They maintain body temperature or homeostasis.
Low levels of growth hormone by the pituitary gland also lead to dwarfism but it is not coupled with low CNS development. Adrenaline is secreted by a pair of the adrenal gland, located superiorly to kidneys. It causes a rise in blood pressure along with the heartbeat. It also acts on skeletal muscles during the time of emergency or stress. The parathyroid gland secretes parathormone that acts on bones and kidneys to raise blood calcium levels.
So, the correct answer is ‘Thyroxine.’

Note: -The thyroid gland releases calcitonin also which is a peptide hormone.
-It is secreted in response to higher calcium levels in the body.
-It promotes osteoblastic activity where plasma calcium concentration is decreased by reducing its mobilization from bones.