3: Anatomy and physiology of the thyroid gland Flashcards Preview

Endocrine Week 3 2017/18 > 3: Anatomy and physiology of the thyroid gland > Flashcards

Flashcards in 3: Anatomy and physiology of the thyroid gland Deck (53)
Loading flashcards...
1

What is the master gland of the endocrine system?

Pituitary gland

2

In relation to the thyroid, which hormone is secreted by the hypothalamus and acts on the pituitary gland?

TRH

Thyrotrophin releasing hormone

3

Which hormone is secreted by the pituitary gland and acts on the thyroid?

TSH

Thyroid stimulating hormone

4

Which hormones are released by the thyroid gland?

Thyroxine (T4)

Tri-iodothyronine (T3)

Calcitonin

5

Which glands are found on the posterior aspect of the thyroid?

4 parathyroid glands

6

Which nerve could be damaged in thyroid surgery, almost certainly getting you sued?

Recurrent laryngeal nerve

Unilateral - swallowing issues

Bilateral - lack of phonation

7

Removal of the parathyroid glands during thyroid surgery may result in ___.

hypoparathyroidism

8

Thyroid pathologies have typical appearances on which imaging modality?

Ultrasound

9

The thyroid takes up ___. This allows it to be seen on radionucleotide imaging.

iodine

10

From wikiped:

Low uptake suggests thyroiditis, high uptake suggests Graves' disease,[4] and unevenness in uptake suggests the presence of a nodule.

11

What carrier protein is found in the follicle of thyroid cells?

Thyroglobulin (which carries T3 and T4)

12

What is the fluid area found in the central of a follicle?

Colloid

13

Thyroglobulin is found in which part of a thyroid follicle?

Colloid

14

What binds to thyroglobulin to produce thyroid hormones?

Iodine

15

How are thyroid hormones transported from the colloid to the follicular cells once they have been produced?

Pinocytosis

16

How are thyroid hormones transported from the follicular cells into the bloodstream?

Exocytosis

17

Where are C cells found?

What do they produce?

Parafollicular

Calcitonin

18

Iodine binds to what part of thyroglobulin to form the precursors of thyroid hormones?

Tyrosine residue

19

What is the biggest cause of hypothyroidism (i.e lack of thyroid hormone production) globally?

Iodine deficiency

20

What antithyroid drugs are used to treat hyperthyroidism?

How do they work?

Carbimazole, propylthiouracil

Inhibit iodination of thyroglobulin

21

Why do anti-thyroid drugs have a long onset of action?

Prevent NEW thyroid hormones from being made

Still residual thyroid hormone floatin around, and it's got a half life of around 10 days

22

Which thyroid hormone is 

a) most commonly secreted

b) most potent?

a) T4

b) T3

23

T4 must be converted to __ before it can work.

T3

More potent

24

Where is T4 converted to T3?

Liver and kidneys

25

Thyroid hormones are (hydrophilic / hydrophobic).

Hydrophobic

26

How are thyroid hormones similar to steroids?

Hydrophobic

Pass through cell membrane

Act on nuclear receptors to alter metabolism

Require carrier proteins to travel in blood

27

Thyroid hormones are released from follicular cells in response to which hormone?

TSH

28

On which carrier proteins are thyroid hormones transported in the blood?

Thyroxine binding globulin (TBG)

Transthyretin

Albuminnnn

29

When thyroid hormones are bound to carrier proteins, they are ___.

inactive

30

Free thyroid hormones are (inactive / active).

active