Final answer:
Goiter is an enlargement of the thyroid gland caused by an iodine deficiency, leading to a decrease in the production of thyroid hormones and symptoms of hypothyroidism. Increasing TSH levels due to low T3 and T4 does not compensate for the lack of iodine, resulting in a goiter. Prevention includes consuming iodized salt or iodine supplements.
Step-by-step explanation:
Goiter is an enlargement of the thyroid gland caused by a deficiency of iodine. This deficiency leads to a decrease in the synthesis of thyroid hormones T3 (triiodothyronine) and T4 (thyroxine). The body attempts to compensate for low hormone levels by increasing the production of Thyroid Stimulating Hormone (TSH), which triggers the thyroid to produce more hormones. However, without sufficient iodine, TSH cannot produce the thyroid hormones, leading to an excessive accumulation of colloid in the thyroid gland and thereby causing a goiter.
Regarding the symptoms caused by goiter, one would expect to see signs of hypothyroidism. This is characterized by weight gain, sensitivity to cold, and reduced mental activity, as the thyroid is not producing enough hormones to maintain a normal metabolism. On the contrary, hyperthyroidism involves an overproduction of thyroid hormones, resulting in symptoms such as weight loss, profuse sweating, and increased heart rate, but is not typically associated with iodine deficiency.
Prevention of this condition often includes the ingestion of iodized salt or iodine supplements, especially in areas where natural iodine levels are low. This practice has significantly decreased the prevalence of goiter in many parts of the world.