W24/L3: Iodine & Thyroid hormones Flashcards
In what regions is iodine abundant?
The ocean
What’s the RDI for iodine?
150μg
What does iodine deficiency give rise to?
Goitre
What does maternal iodine deficiency cause?
Cretinism
Which iodine isomer is used for thyroid ablation?
I-131
What characteristics of iodine make it a good x-ray contrast material?
High atomic number
Low toxicity
Easily attached to organic compounds
What are the best dietary sources of iodine?
Marine sources!
Fish, shellfish, kelp
Historically, which people got goitre?
The wealthy (who ate refined salt), and people living far inland)
Hyperthyroidism is visibly distinguishable from iodine deficiency on the basis of:
Exophthalmia
as well as goitre
What are goitrogens?
Compounds that inhibit iodine uptake in thyroid
What foods are goitrogens commonly found in?
Cruciferous veggies
Soy, kale, brussel sprouts*
Cretinism can present with
Mental retardation
Growth retardation (diminished stature)
In what proportions does the thyroid product T3 and T4?
80% T4 / 20% T3
Which thyroid hormone is responsible for almost all the hormone activity of them?
T3
How does iodine get into the thyroid?
Via the Na+, I- symport (NIS)
Where does the energy that powers NIS come from?
The sodium-potassium ATPase
What’s the most common form of hyperthyroidism?
Graves’ disease
What type of hypersensitivity is Graves’ disease?
Type II
What are some signs/symptoms of hypothyroidism?
Goitre
Dry, coarse hair, dry skin, brittle nails
Weight gain, puffy face, constipation
Heavy periods, infertility
Bradycardia
Arthritis
Cold intolerance
Depression, fatigue, forgetfulness
What are some signs/symptoms of hyperthyroidism
Goitre
Hairloss, soft nails
Weight loss, muscle wasting, frequent bowel movements
Scant periods
Tachycardia
Tremour
Heat intolerance