Question 1

Which of the following best describes the location of the thyroid gland?

Accepted Answer

Anterior neck, on the trachea just inferior to the larynx

Question 2

What is the primary function of follicular cells in the thyroid gland?

Accepted Answer

Production of thyroglobulin and synthesis of thyroid hormone

Question 3

Which hormone is referred to as thyroxine, and how many iodine atoms does it contain?

Accepted Answer

Thyroxine; four iodine atoms

Question 4

What is the calorigenic effect of thyroid hormone (TH)?

Accepted Answer

Increasing basal metabolic rate and body heat production

Question 5

Which of the following steps occurs FIRST in the synthesis of thyroid hormone?

Accepted Answer

Thyroglobulin is synthesized and discharged into the follicle lumen

Question 6

A patient presents with an enlarged thyroid gland (goiter) and symptoms of myxedema. Which of the following is the most likely cause?

Accepted Answer

Lack of dietary iodine

Question 7

Which equation best represents the conversion of thyroxine ($$T_4) to $$triiodothyronine ($$T_3) in $$peripheral tissues?

Accepted Answer

$$T_4$$ \rightarrow $$T_3 + I$

Question 8

Why does thyroid hormone require plasma proteins for transport in the blood?

Accepted Answer

TH is hydrophobic and must bind to plasma proteins to remain soluble in blood

Question 9

Which cells in the thyroid gland secrete calcitonin?

Accepted Answer

Parafollicular cells (C cells)

Question 10

A newborn is diagnosed with congenital hypothyroidism. Which of the following is a likely consequence if untreated?

Accepted Answer

Impaired growth and brain development

Question 11

Which of the following best describes the negative feedback loop regulating thyroid hormone levels?

Accepted Answer

Falling TH levels trigger TSH release; rising TH levels inhibit TSH release

Question 12

Which of the following is NOT a normal physiological effect of thyroid hormone?

Accepted Answer

Inhibits glucose metabolism in peripheral tissues

Question 13

Which of the following would most likely be observed in a patient with Graves' disease?

Accepted Answer

Elevated metabolic rate, sweating, and bulging eyes (exophthalmos)

Question 14

Which process is directly inhibited by pharmacological doses of calcitonin?

Accepted Answer

Bone resorption by osteoclasts

Question 15

Which of the following best explains why goiters develop in iodine-deficient regions?

Accepted Answer

TSH stimulates the thyroid gland to produce more colloid, but without iodine, functional hormones cannot be made

Question 16

Which of the following is a direct effect of thyroid hormone on the cardiovascular system?

Accepted Answer

Promotes normal functioning of the heart

Question 17

Which of the following is TRUE regarding the storage of thyroid hormone?

Accepted Answer

Thyroid hormone is stored extracellularly in the follicle lumen as colloid

Question 18

Which of the following would most likely inhibit TSH release?

Accepted Answer

Rising levels of glucocorticoids

Question 19

Which of the following is a consequence of hypersecretion of thyroid hormone on the muscular system?

Accepted Answer

Muscle atrophy and weakness

Question 20

Which of the following best describes the effect of thyroid hormone on the gastrointestinal (GI) system?

Accepted Answer

Promotes normal GI motility and tone

The Thyroid Gland: Structure, Function, and Clinical Significance

Study Guide - Practice Questions