The document discusses goiter, which is an enlargement of the thyroid gland caused by a lack of iodine. It can be caused by Graves' disease, Hashimoto's disease, or thyroid cancer. Without enough iodine, the thyroid is unable to produce thyroid hormones. Goiter affects the body's homeostasis by preventing the production of thyroid hormones. Common symptoms include a swollen throat and difficulty swallowing or breathing. Treatment options include medication like levothyroxine to replace thyroid hormones, surgery, or radioactive iodine. Consuming iodized salt can help prevent goiter.