Chapter 10: Micromineral (Iodine) Flashcards
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
iodine - deficiency
developmental defect in infants characterized by a dry thick skin, puffy face, and eyelids, enlarge tongue, husky voice, decreased reproductive ability, and mental retardation
cretinism
iodine - toxicity
also known as Grave’s disease or exophthalmic goiter
increased basal metabolism, goiter, and disturbances in the autonomic nervous systems causing hyper irritability and increased creatinine metabolism
hyperthyroidism
hyperthyroidism is also known as
grave’s disease or exophthalmic goiter
iodine - deficiency
severe iodine deficiency can produce _____ which is characterized by a dry, waxy type swelling, with abnormal deposits of mucoproteins under the skin
myxedema
iodine - recommended intake
for infants to children (0-5 years old) both male and female
90 ug
iodine - recommended intake
for children (6-12 years old) both male and female
120 ug
iodine - recommended intake
for children and adults (13->70 years old) both male and female
150 ug
iodine - recommended intake
for pregnant and lactating
150 +100
iodine - recommended intake
the recommended intake for adult corresponds to the intake necessary to maintain _____ level above the critical limit likely to be associated with the onset of goiter
it corresponds to the daily iodine urinary excretion of _____ ug/L
plasma iodide; 100 ug/L
pregnant and lactating mothers
at risk of developing iodine deficiency
