Biology / Unit 12 Bio 2939 short lesson, about 20 seconds
Thyroid Hormones and Metabolic Rate
Captions available
The idea
Thyroid hormones T3 and T4, released under thyroid-stimulating hormone control, raise cellular metabolic rate and heat production by increasing mitochondrial ATP output across most tissue.
In practice
Inadequate dietary iodine prevents T3 and T4 synthesis, producing the thyroid enlargement called goiter as TSH keeps stimulating the gland.
Where people slip
T4 releases in far greater amounts, but T3 is the more active form once tissues convert it.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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