Chapter 10: Micromineral (Iodine) Flashcards
(34 cards)
required as a component of thyroid hormone, thyroxine (t4) and triiodothyronine (t3)
iodine
2 thyroid hormones
thyroxine; triiodothyronine
thyroid hormone (t4)
thyroxine
thyroid hormone (t3)
triiodothyronine
dietary iodine is in the form of
iodide
iodine - functions
a part of the _____
essential in regulating body’s growth, development, and metabolic rate
thyroid hormone
iodine - functions
_____ and _____ are required for normal energy metabolism, thermoregulation, and intermediary metabolism
thyroxine and triiodothyronine
iodine - functions
essential in the conversion of _____ to vitamin a
carotene
iodine - functions
protein synthesis, carbohydrate production, rbc production, nerve muscle function
-
iodine - absorption and metabolism
iodine is absorbed mainly in the _____, distributed in the extracellular fluids
small intestine
iodine - absorption and metabolism
reduced first to the absorbable _____; absorbed iodide is converted to iodine before it enters the circulatory system
iodide
iodine - absorption and metabolism
1/3 of the absorbed iodide in the blood is taken up by the _____ for synthesis of the thyroid hormones thyroxine (t4) and triiodothyronine (t3)
thyroid gland
iodine - absorption and metabolism
t3 and t4 circulate in the bloodstream bound to thyroxine binding globulin, prealbumin, and albumin
_____ is biologically more potent than _____
t3; t4
iodine - absorption and metabolism
the release of the t3/t4 by the thyroid is usually at a ratio of _____
this ratio is decreased when there is lack of iodine
20/1
iodine - absorption and metabolism
the rest of the iodide is excreted in the _____, some amounts are lost via the skin and feces
urine
iodine - absorption and metabolism
the metabolism of iodine occurs under the _____
hormonal feedback control
iodine - absorption and metabolism
the uptake, synthesis, and release of iodine by the thyroid gland is stimulated by _____ released by the anterior pituitary gland
thyroid stimulating hormone
iodine - interrelationship with other nutrients
from cabbage, kale, cauliflower, broccoli, turnip, brussel sprouts, and mustard greens
are substances that interferes with iodine metabolism inhibiting hormogenesis
goitrogens
iodine - interrelationship with other nutrients
the goitrogens that affect iodide uptake by the thyroid glans, organification of the iodide or hormone release from the thyroid cells:
halide ions: bromide (br)
astatide (at-)
thiocyanate (SCN-)
-
iodine - interrelationship with other nutrients
cassava contains _____ with thiocyanates as metabolites
cyanogen glucosides
iodine - food sources
iodized salt, seafoods, seaweeds
iodine
iodine - deficiency
most common forms of iodine deficiency are: _____ and _____
endemic goiter and cretinism
iodine - deficiency
lack of iodine results in an enlargement of the _____ (goiter)
thyroid gland
iodine - deficiency
enlargement of thyroid gland is due to over stimulation of the thyroid by _____ and _____, which are present in increased levels in an attempt to produce more circulating t3 and t3
TRF and TSH
thyrotropin-releasing factor;
thyroid-stimulating hormone