Endocrine System & Hormone Balance Flashcards

Which mineral is essential for the deiodinase enzymes that convert inactive T4 into active T3?

Answer: Selenium

Selenium-dependent deiodinases remove an iodine atom from T4 to form active T3.

Which antibody test is most commonly elevated in Hashimoto's thyroiditis?

Answer: Anti-TPO antibodies

Thyroid peroxidase antibodies indicate autoimmune attack on the thyroid in Hashimoto's.

Which amino acid is the backbone used to build thyroid hormones?

Answer: Tyrosine

Thyroglobulin's tyrosine residues are iodinated to form T3 and T4.

Which hormone from the anterior pituitary stimulates the thyroid gland to release hormones?

Answer: TSH

Thyroid-stimulating hormone signals the thyroid to produce and release T4 and T3.

Which practice best reduces the goitrogenic effect of cruciferous vegetables for someone with low thyroid function?

Answer: Cooking or steaming them

Heat inactivates much of the myrosinase enzyme that forms goitrogenic compounds.

Which condition commonly raises reverse T3 (rT3) at the expense of active T3?

Answer: Chronic stress or severe calorie restriction

Stress and under-eating shift T4 conversion toward the inactive rT3 form.

Which food is among the richest natural sources of iodine?

Answer: Kelp (seaweed)

Sea vegetables such as kelp concentrate iodine from seawater.