13. A patient has a goiter associated with high plasma levels of both TRH and TSH. Heart
rate is elevated. The patient most likely has:
A. Endemic goiter
B. A hypothalamic tumor secreting large amounts of TRH
C. A pituitary tumor secreting large amounts of TSH
D. Graves’ disease
14. Which of the following regarding T4 is false?
A. Secretion rate from thyroid exceeds that of T3
B. Secretion rate from thyroid is decreased by propylthiouracil
C. Plasma concentration is less than that of T3
D. Peripheral deiodination is the major source of circulating T3
15. A pregnant patient has a normal hypothalamo-hypophysial axis. A blood sample reveals
elevations in the concentrations of thyroxine-binding globulin and total thyroid
hormones, and low plasma TSH concentration. Assuming steady state conditions one
would expect:
A. Graves’ disease
B. Hypothyroidism
C. Euthyroidism
D. High plasma levels of thyrotropin releasing hormone
16. A patient has a goiter and exhibits sweating and tachycardia. Plasma levels of TSH are
elevated but plasma levels of thyrotropin releasing hormone are reduced. This patient
probably has:
A. Graves’ disease
B. Hyperthyroidism due to a primary abnormality in the pituitary gland
C. Hyperthyroidism due to a primary abnormality in the hypothalamus
D. Hypothyroidism due to an abnormality in the thyroid gland
17. A patient has a pronounced goiter associated with increased plasma levels of TSH. The
patient complains of constipation and lethargy. Which of the following is the most likely
explanation for these findings?
A. The patient is taking thyroid extract
B. The patient is taking propylthiouracil
C. The patient is consuming large amounts of iodine
D. The patient has a pituitary adenoma
E. The patient has Graves’ disease