Thyroid Hormone

Question 1

The material in the center of a thyroid follicle surrounded by follicular epithelial cells is called .

Answer 1

Colloid

Question 2

The increased oxygen consumption that stems from thyroid hormone release causes a(n) (increase/decrease) in cardiac output.

Answer 2

INCREASE

Question 3

The freshly synthesized thyroid hormones in colloid are attached to .

Answer 3

Thyroglobulin

Question 4

Tetraiodothyronine is converted to triiodothyronine by the enzyme by removing one atom from I2.

Answer 4

5-deiodinase

Question 5

Tetraiodothyronine is formed by the combination of two molecules.

Answer 5

Diiodotyrosine molecule

Question 6

The form of thyroid hormone that is more active is (triiodothyronine/tetraiodothyronine) .

Answer 6

Triiodothyronine (T3)

Question 7

Thyroglobulin contains a large amount of (amino acid) .

Answer 7

TYROSINE

Question 8

The second messenger for thyroid stimulating hormone is .

Answer 8

cAMP

Question 9

The transports iodine from blood into follicular epithelial cells.

Answer 9

Na I symporter

Question 10

Triiodothyronine binds to a receptor, and then stimulates DNA transcription by binding to a thyroid-regulatory element.

Answer 10

Nuclear

Question 11

The effect occurs when large amounts I- inhibit organification, which is the combination of I2 and tyrosine of thyroglobulin to form monoiodotyrosine and diiodotyrosine.

Answer 11

Wolff-Chaikoff effect

Question 12

Thyroid hormone circulates the bloodstream bound to .

Answer 12

THYROXINE BINDING GLOBULIN

Question 13

The thyroid gland synthesizes thyroid hormone in its epithelial cells.

Answer 13

Follicular

Question 14

Decreased thyroxine-binding globulin, such as in hepatic failure, results in (increased/decreased) levels of free thyroid hormones and decreased synthesis of thyroid hormones.

Answer 14

Increased

Question 15

Thyroid gland growth is regulated by hormone

Answer 15

TSH

Question 16

Thiocyanate and perchlorate are (competitive/noncompetitive) inhibitors of Na+-I- cotransport.

Answer 16

COMPETITIVE

Question 17

Increased basal metabolic rate, weight loss, sweating, and increased heat production are all symptoms of (hyperthyroidism/hypothyroidism) .

Answer 17

HYPERTHYROIDISM

Question 18

The formation of (triiodothyronine/tetraiodothyronine) is much faster than the other.

Answer 18

Tetraidothyronine

Question 19

A dietary I- deficiency appears similar to a deficiency of (enzyme) .

Answer 19

Thyroid deiodinase

Question 20

The hepatic breakdown of thyroxine-binding globulin is inhibited during pregnancy due to high levels of , causing an increased synthesis of thyroid hormones by removing negative feedback.

Answer 20

Estrogen

Question 21

is formed by the combination of one monoiodotyrosine and one diiodotyrosine molecule.

Answer 21

Triiodothyronine

Question 22

The Na+-I- cotransport pump increases activity when the body has too (much/little) iodine.

Answer 22

little

Question 23

The T3 resin uptake test assesses the circulating levels of .

Answer 23

Thyroxine binding globulin

Question 24

is released from the hypothalamus to stimulate secretion of thyroid stimulating hormone from the anterior pituitary.

Answer 24

THYROTROPIN RELEASING HORMONE

Question 25

Heart rate and contractility increase when thyroid hormone is released due to its effect on their receptors.

Answer 25

Beta 1 adrenergic receptors

Question 26

Iodine ions are oxidized to I2 by (enzyme) when they reach the apical membrane of the cell.

Answer 26

Thyroid Peroxidase (TPO)

Question 27

Thyroid hormone (increases/decreases) basal metabolic rate and body temperature through increased oxygen consumption.

Answer 27

INCREASES

Question 28

The nuclei of the hypothalamus release oxytocin

Answer 28

Paraventricular

Question 29

The thyroid gland secretes 90% of its thyroid hormone in the form of (triiodothyronine/tetraiodothyronine)

Answer 29

tetraiodothyronine