Regulation of thyroid function — Flashcards

Flashcard 1: Thyroid-stimulating hormone (TSH) secretion is decreased in response to _____

Answer: free T3/T4

Flashcard 2: In the circulation, most of the T3 and T4 is bound to _____

Answer: thyroxine-binding globulin (TBG)

Flashcard 3: The levels of free thyroid hormone are _____ in pregnancy and oral contraceptive use

Answer: normal

Flashcard 4: What effect does excessive I- intake have on thyroid hormone secretion?_____

Answer: Decreases secretion (Wolff-Chaikoff effect)

Flashcard 5: What effect does increased TBG levels have on thyroid hormone secretion?_____

Answer: Increases secretion

Flashcard 6: What is the result when thyroid-stimulating immunoglobulins bind to TSH receptors of the thyroid gland?_____

Answer: They stimulate secretion of T3 and T4

Flashcard 7: Which thyroid hormone (T4 or T3) binds to nuclear receptor with greater affinity?_____

Answer: T3

Flashcard 8: Thyroid hormones (T3/T4) play a role in development of the _____

Answer: CNS

Flashcard 9: What is the effect of the FGF gene?

Answer: stimulates mitosis of underlying mesoderm, lengthening of limbs

Flashcard 10: What is the embryological origin of the adrenal medulla?

Answer: Neural crest cells

Extra: The adrenal medulla is essentially a modified sympathetic ganglion. While the medulla is derived from the neural crest (ectoderm), the adrenal cortex is derived from the mesoderm.