$$2 \times \text{tyrosine} + 4 \times \text{iodine}$$

Question 1

Which structure connects the two lateral lobes of the thyroid gland?

Accepted Answer

Isthmus

Question 2

What is the primary function of the thyroid hormone (TH) in the body?

Accepted Answer

Control of metabolism and basal metabolic rate

Question 3

Which cells in the thyroid gland produce calcitonin?

Accepted Answer

Parafollicular cells

Question 4

Thyroid hormone is synthesized from which precursor protein found in the colloid?

Accepted Answer

Thyroglobulin

Question 5

Which of the following is the correct formula for thyroxine (T4)?

Accepted Answer

$$2 	imes 	ext{tyrosine} + 4 	imes 	ext{iodine}$$

Question 6

Which process describes the attachment of iodine to tyrosine in the synthesis of thyroid hormone?

Accepted Answer

Iodination

Question 7

What is the main effect of calcitonin at higher-than-normal doses?

Accepted Answer

Inhibits osteoclast activity and promotes bone formation

Question 8

Which of the following best describes the calorigenic effect of thyroid hormone?

Accepted Answer

Increase in heat production and basal metabolic rate

Question 9

Thyroid hormone must travel in the bloodstream bound to carriers because:

Accepted Answer

It is lipid soluble

Question 10

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

Accepted Answer

Thyroglobulin is synthesized and transported into the follicle lumen

Question 11

Which form of thyroid hormone is more active at target tissues?

Accepted Answer

Triiodothyronine (T3)

Question 12

What triggers the release of thyroid-stimulating hormone (TSH)?

Accepted Answer

Falling levels of thyroid hormone

Question 13

Which of the following is a critical role of thyroid hormone during development?

Accepted Answer

Normal skeletal and nervous system development

Question 14

If a patient has a deficiency in thyroid hormone during infancy, which of the following outcomes is most likely?

Accepted Answer

Impaired nervous system development

Question 15

Which enzyme is responsible for attaching iodine to tyrosine during thyroid hormone synthesis?

Accepted Answer

Peroxidase

Question 16

What is the role of colloid in the thyroid gland?

Accepted Answer

It contains thyroglobulin proteins with attached iodine for thyroid hormone production

Question 17

Which of the following is a direct effect of thyroid hormone on blood pressure?

Accepted Answer

Maintains normal numbers of adrenergic receptors in blood vessels

Question 18

Which of the following best describes the relationship between TSH and thyroid hormone levels?

Accepted Answer

TSH release is inhibited by rising thyroid hormone levels

Question 19

Which of the following is a function of parafollicular cells in the thyroid gland?

Accepted Answer

Secretion of calcitonin

Question 20

A patient presents with abnormally high levels of calcitonin. Which physiological effect would you expect?

Accepted Answer

Decreased release of calcium from bone matrix

16.7-16.10

Study Guide - Practice Questions