Tyras values Chris values Normal values 106 Serum thyroxine

Tyra\'s values Chris values Normal values 10.6 Serum thyroxine 4.6-12 (T) 1.8 0.3 2.8 0.5-6 Thyrotropin TSH) TSI (immunoglobulins) Normal Normal Normal 125 Serum triiodothyronine 80-180 57 12.3 56.9 Cortisol (ug/dL) 5-23 34.2 ACTH (pg/mL) 2.5 20-50

Solution

A)

For Tyra, the abnormal low values are observed for serum thyroxine (T₄), Thyrotropin (TSH) and serum triiodothyronine (T₃ ). For Chris, Abnormal high value of cortisol and low value of ACTH are observed.

B)

The thyroid gland is a vascular structure containing two large lobes connected by a broad isthmus. It is bilateral and is located inferior to the larynx and anterior to the trachea. The follicular cells of thyroid gland secrete the thyroid hormones such as thyroxin and triiodothyoronine. The extra follicular cells of thyroid gland secrete the calcitonin.

The follicular cells of thyroid gland produce two hormones called thyroxine (tetraiodothyronine-T₄) and triidothyronine (T₃). The thyroxine contains 4 iodine atoms whereas the triiodothyronine contains 3 iodine atoms. Both these hormones have similar actions but the triiodothyronine is five time more potent. The hormones are involved in the regulation of metabolism of carbohydrates, lipids and proteins. They increase the rate of energy released from the carbohydrates, increase the rate of protein synthesis and stimulate the oxidation of lipids. The thyroid hormones are the major factors to determine the calorie consumption by the body at rest to maintain the life. This is known as basal metabolic rate (BMR). The thyroid hormones are required for the growth and development and are much necessary for maturation of nervous system.

The thyroid stimulating hormone (TSH) is produced by anterior pituitary lobe and controls the release of the hormones from thyroid gland. The hypothalamus regulates the TSH secretions partially by producing thyrotropin-releasing hormone (TRH). The thyroid hormones circulating in the blood inhibit the release of both the TRH and TSH. The increase in the thyroid hormones in the blood decreases the secretion of TRH and TSH. Thus, regulating the thyroid secretions by negative feedback mechanism.

C)

In case of Tyra, all the values related to thyroind hormones are consistet with hyposecretion. In case of Chris, value of cortisol is consistent with hyper secretion and value of ACTH is consistent with hyposecretion.

D)

Tyra is expected to develop goiter since her thyroid levels are abnoramlly low and are consistent with hyposecretion. In case of tyra, the likely cause to develop goiter is iodine deficiency.

E)

Goiter caused by iodine deficiency is treated by iodine supplement in the form of Lugol\'s Iodine or KI solution. Goiter developed due to underactive thyroid gland is treated by thyroid supplements.