powerphys 11

be able to explain what hyperthyroidism is

high blood levels of thyroid hormones due to increased secretion of thyroid hormones by the thyroid gland

TRH is produced in what area of the brain?

hypothalamus

the thyroid hormones cause what to happen in the body?

hypothyroidism or hyperthyroidism

be able to explain what techniques were used in the experiments to measure TSH, TRH, and T4

- centrifuge: spin samples resulting in separation of sample components according to weight - radioimmunoassay: T4 antibodies and T4 125 are added to serum sample. antibody binds to both serum hormone and antigen complexes that are insoluble. the insoluble antibody hormone complexes are removed from the solution and the amount of 125 labeled hormone is counted with a gamma counter - immunoradiometric assay: used to measure TSH

know the dependent and independent variables

- dependent: blood levels of TSH and thyroxine and accumulation of radioactive iodine in thyroid - independent: thyroid activity

which statement about thyroid hormones is correct?

- increase basal metabolic rate (BMR) - promote body growth and nervous system development - increase heart rate and blood pressure

be able to explain the 3 main types of hypothyroidism

1) primary hypothyroidism: decrease in secretion of thyroid hormones by the thyroid gland, most commonly due to a dietary deficiency of iodine or as a result of an autoimmune disorder 2) secondary hypothyroidism: pituitary produces insufficient TSH 3) tertiary hypothyroidism: hypothalamic tumors prevent the secretion of normal amounts of TRH which also result in reduced secretion of thyroid hormones

the most common cause of primary hypothyroidism?

dietary deficiency of iodine

which hormone is secreted by the hypothalamus?

TRH

which statement concerning negative feedback control of thyroid hormone secretion is true?

TRH stimulates secretion of TSH

Grave's disease is an autoimmune disease that is the most common cause of hyperthyroidism. Grave's disease results in an increase in thyroid hormone secretion because an antibody is produced that mimics?

TSH

which hormone is secreted by the anterior pituitary?

TSH

in secondary hypothyroidism?

TSH levels are low

TSH is produced in what structure?

anterior pituitary

secondary hypothyroidism is a decrease in thyroid hormone secretion caused by a malfunction of the?

anterior pituitary

the thyroid hormones are controlled by what type of feedback system?

negative feed back loop

TRH is secreted in response to what stimulus?

stimulates the anterior pituitary to secrete TSH

Primary hypothyroidism is a decrease in secretion of thyroid hormones caused by a malfunction of the?

thyroid gland

TSH causes the increase of what hormone?

thyroid hormone

the technique used to observe the relative amount of iodine accumulated by the thyroid gland?

thyroid imaging

TSH responds to the increase in what?

thyroxine (t4)