What is the feedback cycle of thyroid hormone? What diseases are caused by hyperthyroidism? What are the effects of hyperthyroidism? What are the diseases caused by hypothyroidism? What are the symptoms of hypothyroidism? What can hypothyroidism cause in infancts? What are the two methods of measuring T4 and T3 levels in the body? What is the typical test to measure thyroid function what should TSH levels appear as if there is hyperthyroidism? hypothyroidism? What would happen if we were to deliver TRH to someone with hyperthyroidism?

1. What is the feedback cycle of thyroid hormone?

TRH (thyrotropin release hormone) is released from the hypothalams --> TSH from the pituitary --> TSH stimulates I- uptake and T4 and T3 secretion from thyroid --> T3 binds to T3 receptors in hypo/pituitary to inhibit TRH and TSH release

2. What diseases are caused by hyperthyroidism?

Grave's disease, thyrotoxicosis, thyroid storm

3. What are the effects of hyperthyroidism?

Expothalamia, nervousness, decrease body weight, tremor, increased heart rate, increased temp, and goiter

4. What are the diseases caused by hypothyroidism?

Gull's disease, and myxedema

5. What are the symptoms of hypothyroidism?

decrease in thyroid mass, decrease in temp, decrease in heart rate, lethargy, puffy dry skin and brittle hair

6. What can hypothyroidism cause in infancts?

Cretinism -- mental retardation, and stunted grwoth

7. What are the two methods of measuring T4 and T3 levels in the body?

Radio immune assay (RIA) for T4, and thyroid hormone binding ratios -- measures free bindng sites on the blood protein that normally inhibits T4

8. What is the typical test to measure thyroid function

measuring the levels of TSH in the body

9. what should TSH levels appear as if there is hyperthyroidism? hypothyroidism?

low levels of TSH due to the negative feed back loop; hypothyroidism leads to a large amnt of TSH in the blood stream

10. What would happen if we were to deliver TRH to someone with hyperthyroidism?

There is no/very little response of the TSH hormone being secreted -- due to high impact of negative feedback loop