Thyroid Gland Flashcards
Outline some functions of the thyroid hormones;
•increase heat production
•increase oxygen consumption
•promote normal growth
•increase metabolism of proteins,fats and carbohydrates
Between T3 & T4 which plasma thyroid hormone is more active than the other?
T3 is metabolically more active than T4
T4 can readily be converted to T3 in most tissues, particularly liver
Describe regulation or thyroid hormone;
-> negative feedback control of T4 and T3
->free and not total T4/T3 determine feedback
->thyroid stimulating hormone (TSH) and thyroid releasing hormone involved in feedback
What is the first stage of thyroid hormone synthesis;(9)
Dietary iodide (fish,eggs) absorbed rapidly by small intestine
What happens after milk and eggs is absorbed into the small intestine of thyroid hormone synthesis;(9)
Around 1/3 of this iodide is concentrated in thyroid gland and 2/3 is excreted by kidneys
What happens after the kidney excretes the solution in thyroid hormone synthesis;(9)
Iodide oxidised to iodine in thyroid follicular cells
What happens after iodide is oxidised to iodine in thyroid hormone synthesis;(9)
Iodisation of thyroglobulin forms monoiodotyrosine and diiodotyrosine
What happens after DIT and MIT is formed in thyroid hormone synthesis;(9)
Coupling forms T4 (DIT&DIT) and T3(DIT&MIT)
What happens after T4 and T3 are formed thyroid hormone synthesis;(9)
Thyroid hormones stored and attached to colloid thyroglobulin
What happens after hormones are stored and attached in thyroid hormone synthesis;(9)
They are taking up by follicular cells via pintocytosis
What happens after thyroid is taken up by follicular cells in thyroid hormone synthesis;(9)
Lysosomes use with this droplet and proteases digest thyroglobulin to release thyroid hormones
What happens after
Thyroid hormones are released in thyroid hormone synthesis;(9)
Released thyroid hormones transported in blood bound to thyroxine-binding globulin (TBG)
What age of people is hypothyroidism most common in?
50-60 year olds
How does hypothyroidism occur?
-not enough T4&T3 produced
-under active thyroid gland
Primary cause of hypothyroidism?
Iodine deficiency, anti-thyroid drugs, congenital deficiency
