Define Physiologic Functions of Iodine?
Thyroid hormone performs multiple functions as regulator of cell activity and growth. The hormone has crucial metabolic roles in the foetus, and in the infant post-natally. It promotes growth and maturation of peripheral tissues in the human embryo, the most visible effect seen in the skeletal growth. Delayed bone development has been seen in hormone deficient human embryos. Thyroid hormone influences neuronal cell growth and dendrite development in the embryo. A major effect of foetal iodine deficiency is cretinism, characterized by mental deficiency and deaf mutism.
Postnatally, linear growth, i.e. stature and bone maturation are critically dependent on thyroid hormone. Both are retarded when there is a deficiency of the hormone due to low iodide intakes. The hormone plays an important role in the provision of energy to most cells in the body; the best indicator of this is the energy available for utilization in the basal state, i.e. the basal metabolic rate. In thyroid hormone deficiency, the BMR is lower, slowing the overall cellular activities. Iron deficiency in children is characteristically associated with goitre.