The thyroid gland

Question 1

What type of gland is the thyroid gland?

Answer 1

A ductless alveolar gland

Question 2

What type of cells are thyroid follicular?

Answer 2

Simple cuboidal

Question 3

Sympathetic innervation of the thyroid gland ……. thyroid secretion

Answer 3

Stimulates

Question 4

Goitre is formed as as a result of chronic stimulation by which hormone?

Answer 4

TSH

Question 5

What are the acute actions of TSH hormones on the follicular cells?

Answer 5

Synthesis, storage and secretion of T3 and T4

Question 6

Which has a longer half life? T3 or T4?

Answer 6

T4

Question 7

T3 and T4 is degraded by the removal of iodine. Which organs does this take place?

Answer 7

Liver and kidney

Question 8

What are the actions of thyroid hormones? (3)

Answer 8

1) Increase BMR 2) Stimulates most metabolic pathways 3) Promotes normal growth + development of tissues

Question 9

What is the effect of thyroid hormones on the CV system? (1)

Answer 9

Increases cardiac output

Question 10

What is the effect of thyroid hormones on the nervous system? (3)

Answer 10

1) Increased myelination of nerve fibres and development of neurones 2) Increased speed of reflexes 3) Increased mental activity

Question 11

Hypothyroidism in youth leads to what condition?

Answer 11

Cretinism

Question 12

What some signs and symptoms of hyperthyroidism?

Answer 12

Sweating loads, weight loss, tachycardia, increased appetite, nervousness, irritability, hyper-reflexive and exophthalmus

Question 13

Does Grave’s disease lead to hyper- or hypo- thyroidism?

Answer 13

Hyperthyroidism

Question 14

What condition am I describing? “Production of antibody that stimulates the TSH receptor on follicle cells”

Answer 14

Grave’s disease

Question 15

Carbinazole is used to treat hyperthyroidism. How does this drug work?

Answer 15

It inhibits the incorporation of iodine into thyroglobulin

Question 16

What are the signs and symptoms of hypothyroidism?

Answer 16

Cold intolerance, mild weight gain, bradycardia, constipation, mood swings, poor concentration, oedema

Question 17

What are the two possible mechanisms of Hashimoto’s disease?

Answer 17

Destruction of thyroid follicles or production of antibody that blocks the TSH receptor on follicle cells

Question 18

How would you treat Hashimoto’s disease?

Answer 18

Oral T4

Question 19

Which hormone secreted more from the thyroid gland? T4 or T3?

Answer 19

T4

Question 20

What is the name of the key enzyme associated with thyroid hormone synthesis?

Answer 20

Thyroid peroxidase

Question 21

What are the roles of thyroid peroxidase? (3)

Answer 21

1) Oxidation of iodide to iodine 2) Addition of iodine to tyrosine acceptor residues on thyroglobulin 3) Coupling of MIT or DIT to generate thyroid hormones within the thyroglobulin molecule

Question 22

What is a “free” hormone?

Answer 22

A free hormone is one that is not bound to plasma proteins

Question 23

Is thyroid disease more prevalent in males or females?

Answer 23

Females

Question 24

What is sick euthyroid syndrome?

Answer 24

It is used to describe sick in-patients who frequently have abnormal TFTs despite being euthyroid

Question 25

What is the most common cause of goitre?

Answer 25

Lack of dietary iodine

Question 26

Thyroid hormone is derived from ……

Answer 26

Tyrosine

Question 27

What is the name of the TSH sensitive ion pump that uptakes iodide?

Answer 27

The iodide trap

Question 28

What type of hormone is thyroid stimulating hormone?

Answer 28

A glycoprotein hormone

Question 29

What is subclinical hyperthyroidism?

Answer 29

It is characterised by a low or undetectable concentration of serum TSH with low T3 or T4

Question 30

In Grave’s disease there is increased T3 and T4 and decreased TSH. True or false?

Answer 30

True

Question 31

What is the half life of T4?

Answer 31

5-7 days