THYROID FXN DYSFXN Flashcards
What is the anatomical location of the thyroid gland?
Located in the anterior neck, closely attached to the trachea, with lobes extending from the thyroid cartilage to the 6th tracheal rings.
What are the main hormones secreted by the thyroid gland?
Thyroxine (T4), Triiodothyronine (T3), and reverse T3 (rT3 - biologically inactive).
What is the functional unit of the thyroid gland?
The thyroid follicle.
How much of T4 is converted to T3 in peripheral tissues?
40% of T4 is converted to T3 in peripheral tissues by deiodinases.
What is the most common cause of hypothyroidism worldwide?
Iodine deficiency.
What is Graves’ disease and its cause?
An autoimmune disorder causing hyperthyroidism due to thyroid-stimulating immunoglobulins (TSI) that bind to the TSH receptor.
What is the most common enzyme deficiency in congenital hypothyroidism?
21α-hydroxylase deficiency.
What are the clinical features of hypothyroidism?
Cold intolerance, weight gain, mental slowness, hoarse voice, dry skin, and bradycardia.
What are the biochemical findings in hyperthyroidism?
Suppressed TSH and elevated free T4 (FT4) levels.
What is the role of TSH in thyroid regulation?
TSH stimulates iodination of tyrosine, increases thyroid follicular cell activity, and promotes thyroglobulin proteolysis.
What causes subacute thyroiditis (de Quervain’s thyroiditis)?
Viral infection leading to follicular destruction and thyroid hormone release.
What is the diagnosis for subclinical hypothyroidism?
Elevated TSH with normal T3 and T4 levels.
What is the typical treatment for hypothyroidism?
Hormone replacement therapy, typically with L-thyroxine.
What is Sick Euthyroid Syndrome?
Thyroid-related changes during systemic illness without intrinsic thyroid disease, usually showing low FT3 and TT3.
What are the typical effects of thyroid hormones on metabolism?
Increase basal metabolic rate (BMR), lipid metabolism, carbohydrate metabolism, and protein turnover.
