Thyroid Hormones Quiz

Thyroid Hormones: Synthesis, Mechanism of Action, and Treatment

• The thyroid gland produces the two major hormones, T3 and T4, which maintain optimal metabolism for normal growth and maturation.
• Hypothyroidism, inadequate hormone secretion, causes bradycardia, cold intolerance, mental and physical slowing, and mental retardation and dwarfism in children.
• Hyperthyroidism, excess hormone secretion, causes tachycardia, cardiac arrhythmias, body wasting, nervousness, tremor, and heat intolerance.
• TSH controls thyroid function, and TSH action stimulates iodide uptake by the gland and oxidation to iodine followed by iodination of tyrosines on thyroglobulin.
• Antibodies to thyroid peroxidase are diagnostic for Hashimoto thyroiditis, a common cause of hypothyroidism.
• T4 is enzymatically deiodinated to T3, which enters the nucleus and attaches to specific receptors, promoting RNA formation and protein synthesis responsible for T4 effects.
• Food, calcium preparations, iron salts, and aluminum-containing antacids can decrease T4 absorption.
• Levothyroxine (T4) is preferred over T3 for hypothyroidism treatment, better tolerated, and dosed once daily, achieving steady state in 6 to 8 weeks.
• Toxicity is related to T4 levels and manifests as nervousness, palpitations, tachycardia, heat intolerance, and unexplained weight loss.
• Thioamides, such as PTU and methimazole, inhibit oxidative processes and condensation of iodotyrosines to form T3 and T4, and PTU also blocks peripheral conversion of T4 to T3.
• A pharmacologic dose of iodide inhibits iodination of tyrosines and hormone release, and iodide is used to treat thyroid storm or before surgery.
• β-Blockers, such as metoprolol or propranolol, are effective in blunting the widespread sympathetic stimulation that occurs in hyperthyroidism and used to treat thyroid storm.

Test your knowledge on the fascinating world of thyroid hormones! From their synthesis and mechanism of action, to the diagnosis and treatment of thyroid disorders, this quiz covers all the essential facts. Brush up on the differences between hypothyroidism and hyperthyroidism, the role of TSH, and the effects of commonly used medications. Whether you're a healthcare professional or just interested in learning more about thyroid hormones, this quiz is sure to challenge and inform you.