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29 terms

Physio Endocrine: Thyroid

True or false: Thyroid hormones generally act by modifying the effects of other hormones.
T4/T3 are ______ derivatives and have ______-like solubility with a _____-like structure.
Thyroid follicles' functional cells are the _________ cells, while their lumen is filled mostly with ______.
blood vessels,parafollicular
Thyroid interstitium contains both b____ v_____ and _____ cells for calcitonin release.
The thyroid is the sole utilizer of _______ in the body.
Iodine concentrates into the colloid of thyroid follicles via a ____/I- secondary active transporter, followed by the transporter _______ for primary activate transport into the lumen from the epithelium.
The three steps of thyroid hormone production, carried out by the enzyme __________, include o_______, o_______, and c_______.
Produced in the last step of thyroid hormone synthesis, _____ is made from 2 DITS, while _____ is made from a DIT + MIT.
Thyroid hormone synthesis occurs all within a ________ molecule in the lumen of follicles, which is endocytosed into a _______, and immediately releases the formed hormones into circulation.
75% of thyroid hormones are transported in blood via _____ (high affinity and low capacity), while the remainder is carried by _______ (mostly T4) and by high-capacity albumin.
Overall, more T__ is bound in the blood.
peripheral conversion
The process of changing T4 into T3 is termed ______ _____.
In peripheral conversion, there are several types of _______ which can be utilized in order to provide local control for excess or deficiency of thyroid hormones:
Type 1 and 3 provide _____ regulation while Type 2 provides ______ regulation. (positive/negative)
Lithium, nitrate, and thiocyanide decrease ________ transport in the thyroid, while estrogen, heparin, and pregnanalone increase _______ synthesis.
Androgens, glucocorticoids, and liver/kidney disease all cause a decrease in _______ synthesis, while iodine containing drugs and drugs inhibiting Type 1 and 2 deionidases can cause in increase in T____ and a decrease in T___.
False (it is regulated just by free)
True or false: TRH and TSH are regulated by the total (bound and free) T3/T4 concentration in plasma.
TRH release is stimulated by its _____ generator, and inhibited primarily by high __ and __ concentrations.
TSH release is inhibited primarily by high ____ and ___ concentrations.
The TSH receptor on the ______ has a large extracellular domain where _______ can bind and cause Grave's disease.
True or false: TSH binding stimulates essentially every step of thyroid hormone synthesis.
False (also on adipose and fibroblasts)
True or false: TSH receptors are only found on thyroid epithelial cells.
The Wolf-Chakoff Effect describes that ______ (increased/decreased) free iodine that causes an auto regulation mechanism to decrease ____ receptor activity.
Thyroid hormones bind to a _____receptor, which has a higher affinity for T____, and can form a hetero-dimer with _____.
Thyroid hormones, which have receptors in most cells of the body, _____ BMR by increasing O2 use and heat production, except for in the b_____,S_____, and t_____.
As a result of thyroid hormones, carbs and fats are induced to be ________, while proteins are induced to be ________.
Thyroid hormones cause _______ gut motility, _____ bone formation and respiration, and _____ GH.
Hyper and hypo thyroidisms are in relation to the amount of _____ thyroid hormone in plasma.
Grave's disease,thyroiditis (first part), and toxic adenoma are causes of ____ thyroidism, while Hashimoto's disease, surgical destruction, and end-Grave's disease are causes of _____thyroidism.
hypothyroidism (high levels cause the Walff-chakoff effect)
Extreme high and low iodine levels are possible causes of __________.