On an educational trip to Uttaranchal, Ketki and her friends observe that many local people were having swollen necks, Please help Ketki and her friends to find out the solutions to the following questions.
(a) which probable disease are these people suffering from?
(b) How is it caused?
(c) What effect does this condition have on pregnancy?
(a) People with swollen necks are suffering from goitre due to deficiency of iodine in the their bodies.
(b) Iodine is essential for the synthesis of thyroid hormones- $T_3$ and $T_4$ which are iodinated forms of tyroxine. Deficiency of iodine in our diet results in hypothyroidism and enlargement of the thyroid gland occurs place.
(c) Hypothyroidism during pregnancy causes defective development and abnormalities in growing baby like stunted growth (cretinism) mental retardation, low intelligence quotient (IQ) abnormal skin, deafmutism, etc.
Jet lag is caused by the disruption of the body clock as it is out of synchronisation because of the unfamiliar time zone of the destination. The body experiences different patterns of light and dark conditions than it is normally used to, which disrupts the natural sleep-wake cycle.
Melatonin is a hormone that plays a key role in body rhythms and causes jet lag. After the sun sets, eyes perceive darkness and alert the hypothalamus to begin releasing melatonin, which promotes sleep. Conversely, when the eyes perceive sunlight, they tell the hypothalamus to withhold melatonin production.
However, the hypothalamus can not readjust its schedule instantly and it may take several days, to overcome this problem.
Glucocorticoids, particularly cortisol, produce anti-inflammatory reactions and suppress the immune response. The source for glucocorticoids is the middle zone, which is the widest of three zones, in adrenal cortex called zona fasciculata.
The functions of glucocorticoids as the name suggests they is that they affect carbohydrate metabolism and metabolism of proteins and fats. They stimulate gluconeogenesis, lipolysis and proteolysis.
They also inhibit cellular uptake and utilisation of amino acids. Cortisol is also called stress hormone as it copes with stress.
The thymus gland is a lobular structure located on the dorsal side of the heart and the aorta. It is derived from the endoderm of the embryo. Thymus secretes a hormone named thymosin which stimulates the development of White Blood Cells (WBCs), involved in producing immunity.
Thymus is degenerated in old individuals, resulting in decreased production of thymosin. As result the immune system becomes weak, in old people.