Thyroid Anatomy

Question 1

What tethers the thyroid to the trachea

Answer 1

pre-tacheal fascia

Question 2

What is in the pre-tacheal fascia (5)

Answer 2

thyroid
recurrent layngeal nerve
oesophagus
trachea
pharynx

Question 3

What vertebral level is the thyroid at?

Answer 3

C5-T1

Question 4

Where are the parathyroid glands located on the thyroid?

Answer 4

posterior aspect

Question 5

What is the function of parathyroid glands?

Answer 5

calcium homeostasis

Question 6

How many parathyroid glands are there?

Answer 6

four

Question 7

2 main sources of thyroid blood supply

Answer 7

superior thyroid artery

inferior thyroid artery

Question 8

What is the superior thyroid artery a branch of?

Answer 8

external carotid artery

Question 9

What is the inferior thyroid artery a branch of?

Answer 9

thyrocervical trunk

from the subclavian artery

Question 10

Venous drainage of the thyroid occurs through..

Answer 10

superior
middle
inferior thyroid veins

Question 11

Which veins drain to the internal jugular vein?

Answer 11

superior

middle thyroid vein

Question 12

Which vein drains to the brachiocephalic vein

Answer 12

inferior thyroid vein

Question 13

What innervates the thyroid?

Answer 13

sympathetic fibres

from superior, middle and inferior cervical ganglia

Question 14

What travels behind the thyroid to supply laryngeal muscles?

Answer 14

recurrent laryngeal nerve

Question 15

Perithyroid
Pre-laryngeal
Pre-tracheal
Paratracheal
Superior and inferior deep cervical

Answer 15

Lymph nodes draining the thyroid

Question 16

What is the site of hormone production and storage in the thyroid?

Answer 16

colloid

Question 17

Function of C cells/parafollicular cells?

Answer 17

secrete calcitonin

for calcium homeostasis

Question 18

Thyroid hormones

Answer 18

Thyroxine (T4)
Triiodothyronine (T3)
Calcitonin

Question 19

Most abundant thyroid hormone

Answer 19

T4

Question 20

Most active thyroid hormone

Answer 20

T3

Question 21

Thyroid transport proteins

Answer 21

thyroid binding globulin
albumin
transthyretin

Question 22

In response to stimuli, what does the hypothalamus release?

Answer 22

thyrotropin-releasing hormone (TRH)

Question 23

In response to TRH, what does the anterior pituitary release?

Answer 23

thyroid stimulating hormone (TSH)

Question 24

What does TSH stimulate the production of?

Answer 24

T3 and T4

Question 25

What is the negative feedback loop of the thyroid

Answer 25

Increase in T3 and T4 results in | reduction in TRH and TSH

Question 26

What happens to T3 and T4 in Hypothyroidism

Answer 26

decreases

Question 27

What happens to T3 and T4 in Hyperthyroidism

Answer 27

increases

Question 28

What is most plasma T3 derived from?

Answer 28

peripheral metabolism of T4

Question 29

What does conversion from T4 to T3 require?

Answer 29

removal of iodine by a deiodinase enzyme

Question 30

What can T4 also be metabolised to?

Answer 30

reverse T3 (rT3)

Question 31

Thyroid hormone receptors

Answer 31

TRa1 TRa2 TRb1 TRb2

Question 32

Which hormone receptor does not bind T3?

Answer 32

TRa2

Question 33

What happens when T3 binds to the thyroid hormone receptor

Answer 33

gene transcription activated form mRNA followed by a translation to a protein

Question 34

Function of thyroid hormones in metabolism

Answer 34

``` increase in basal metabolic rate glycolysis O2 consumption thermogenesis protein turnover ```

Question 35

Function of thyroid hormones in cardiovascular system

Answer 35

increase in systolic pressure increase in B-adrenergic receptor enhances catecholamine actions