Thyroid Hormone System Flashcards
What is the center of a thyroid cell that synthesizes and secretes thyroid hormone?
the colloid
What is the protein that holds the iodide molecules with in the thyroid hormone?
thyroglobulin
What enzyme oxidizes iodide to iodine in the body?
thyroid peroxidase
Does T3 act like a hydrophilic or a steroid messenger?
It acts like a steroid messenger!
What is the FIRST test for thyroid issues?
TSH!
What does high TSH tell us?
High TSH = hypOthyroid
What does low TSH tell us?
low TSH= hyperthyroid
What test do you administer to find out if the thyroid disorder is autoimmune?
Anti-Thyroid antibodies
What is TSI?
Thyroid stimulating immunoglobin…looking for hyperthyroidism
Is a radioactive iodide scan showing anatomy or function?
Anatomy: can see hot and cold spots of iodine uptake
What are levels of T4 and T3 like during hyperthyroidism?
High levels of T4 and T3
What are TSH levels with hyperthyroidism?
Low TSH (unless it’s a VERY rare TSH producing tumor)
What is the ONLY situation for proptosis?
Graves disease
Which thyroid condition are goiters MOSTLY associated with? What is the exception?
Mostly hyperthyroid with the exception of high TSH causing a goiter in hypothyroidism
Which thyroid condition is associated with vasodilation?
hyperthyroid, excess blood flow and heat. (Vasoconstriction for hypo, poor blood flow and cold intolerance)
Antibodies (Thyroid Stimulating Immunoglobulin) activate the TSH receptor… high Uptake and diffuse and large scan
Graves Disease
Areas of the thyroid escape TSH control. Patchty iodine uptake
multi nodular goiter
An area with a mutation in the TSH receptor. High uptake in only one area
hot nodule
An inflammed gland releasing stored hormone. No uptake!What is the mechanism for thyroiditis? Iodine uptake?
thyroiditis
No uptake of Iodine, no mechanism. Just hyperthyroidism, maybe prescribed by a doctor?
Exogenous T4, T3
What has a high diffuse uptake on the iodide scan and enlarged thyroid gland, but is very rare?
TSH-producing tumor
What do eye muscles become infiltrated with in graves eye disease?
mucopolysaccarides, lymphocytes, and excess fat
What disease has the result of FIBROTIC and scarred eye muscles accompanied with blurred vision?
Graves eye disease (you got that wrong on the quiz. idiot!)
Does smoking have an effect on graves eye disease?
yes, smoking causes it to become worse
What are the three main treatments for hyperthyroidism?
1.Radio-active iodine (usually become hypothyroid before Dr can adjust back 2. Anti-Thyroid drugs (inhibit synthesis of T3 from T4) (side effects present) 3. Surgery (w/ a GOOD physician)
What can each of these individually cause? Autoimmune destruction (hasimoto thyroiditis), congenital defects in hormone synthesis, iodine deficiency, radioactive iodine/surgery, anti-thyroid drugs.
Primary Hypothyroidism!!
Where is a secondary hypothyroidism caused?
The pituitary
Where is a tertiary hypothyroid problem caused?
The hypothalamus
What are T4/T3 levels and TSH levels with a thyroid effect? (primary)
low T3/T4 and high TSH
What are the T4/T3 levels and TSH levels with a pituitary effect? (secondary)
low T3/T4 and low TSH
What are the T4/T3 levels and TSH levels in a hypothalamic defect? (tertiary)
low T3/T4 low TSH
Are the results of hypothyroidism reversible?
Yes, if caught and treated in time
What is the hypothalamus condition, caused with no intervention as a child, results in short stature and no bone growth?
Cretinism
What is the only named treatment for hypothyroidism?
Thyroxine! (give as T4 and the body will synthesize to T3 as needed)
Would you expect a goiter with hypothyroidism due to pituitary insufficiency? (secondary hypothyroidism)
NO! The only goiter associated with hypothyroidism is due to high TSH. With a secondary hypothyroidism we would have no TSH.
