NURO 671 Final - Module 6 (Thyroid) Questions
With Complete Solutions
names for T3 and T4 correct answer: T3 - triiodothyronine T4 - thyroxine
what state are free T3 and free T4 in? correct answer: unbound in blood and biologically active
what is TBG? what does it do? how does it change in pregnancy? correct answer: thyroid binding globulin - carrier for thyroid hormones in the blood
in pregnancy it changes, and the implication of that is that it binds the free T3 an free T4. So it affects how much unbound free T3 and free T4 are, which affects the tests you're going to be using.
why is iodine important? explain what happens on the thyrocyte with iodine? correct answer: it's a key ingredient to make T3 and T4. there are little iodide traps on the thyrocyte and they actively bring the iodine into the cell, then it gets bound up with the thyroid precursor and becomes the thyroid hormone iodine vs iodide? correct answer: used interchangeably here because as soon as iodine is ingested, it changes in the stomach to iodide
what happens with iodine deficiency? severe prolonged deficiency? correct answer: leads to hyperplasia of the thyroid gland - enlarged because trying to work overtime to produce thyroid hormones without adequate and easy access to iodine severe prolonged - irreversible hyperplasia (goiter)
explain the iodine deficiency pathway in pregnancy correct answer: iodine deficiency in pregnancy will cause a relative thyroid hormone deficiency which will stimulate the thyroid gland, and eventually lead to goiter formation
directly inverse proportion - less iodine, more hyperplasia, eventually you'll have the full stigmata of goiter
varying screening recommendations for thyroid disease in pregnancy correct answer: American Thyroid Society - "insufficient evidence" for/against universal screening
Only screen women with hx of thyroid disease or symtpoms - American Association Clinical Endocrinology - The Endocrine Society
- USPSTF
- ACOG normal changes of the thyroid in pregnancy correct answer: thyroid is critically important in pregnancy and supports all the metabolic changes of pregnancy
1. thyroid hormones change to support the metabolic changes of pregnancy for fats, proteins, and carbs
2. some diffuse enlargement from the fact that the gland is so active
3. thyroid gland is producing hormones that are freely transported across the placenta
explain the relationship of beta-hCG and the thyroid correct answer: TBG increases drastically during pregnancy, which makes more T4 bound to TBG. This cases TSH to increase and more thyroid hormones are released
flowchart of NORMAL regulation of thyroid function during normal pregnancy correct answer: the impact of estrogen on thyroid function (left) impact of hCG on thyroid hormone production (middle)
transplacental loss (right)
how to TSH levels change in normal pregnancy? correct answer:
drops in 1st trimester
returns to non-pregnant levels by 2nd trimester
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