Thyroid glands and hormones

Question 1

What is the isthmus (the narrow part) of the thyroid gland in line with in the neck

Answer 1

1st tracheal cartilage

Question 2

Which triangle in the neck is the thyroid gland found

Answer 2

Lower anterior

Question 3

Where are the parathyroid glands found

Answer 3

Posterior aspect of the thyroid gland

Question 4

Where does the thyroid gland develop from

Answer 4

Endodermal down growth of the floor of the pharynx

Question 5

WHt does the thyroid gland grow from and what does it form

Answer 5

Foramen caecum to thyroid cartilage and forms thyroglossal duct

Question 6

What is the thyroglossal duct

-How are thyroglossal cysts formed

Answer 6

As thyroid gland descends, it forms a small channel called the thyroglossal duct. It usually disappears once thyroid gland reaches its final position in the neck

-When fluid collects in this pocket

Question 7

What do you need to check for if removing thyroid

Answer 7

Ectopic thyroid tissue

Question 8

What does the thyroid produce

Answer 8

T3+T4

Calcitonin

Question 9

What is the type of cell in the thyroid gland

Answer 9

cuboidal epithelium

Question 10

What is colloid and how does the thyroid deal with this

Answer 10

Thyroid gland stores inactive hormones in the lumen of the follicles. This is activated by the follicular cells on demand which take up the colloid, activate it and pass it to the bloodstream

Question 11

What are T3 and T4 and which is the active form

Answer 11

T4 is converted to T3 (Active form)

They regulate basal metabolic rate and growth and maturation of nerve

Question 12

What is the secretion of T3 and T4 regulated by

Answer 12

anterior pituitary

Question 13

What is the secretion of T3 and T4 regulated by

Answer 13

TSH

Question 14

What is the role of calcitonin and mechanism of action

Answer 14

Regulates blood calcium level (lowers)

• Inhibits osteoclast reabsorption of bone
• Increases osteoblast activity

Question 15

What is calcitonin the antagonist for

Answer 15

PTH

Question 16

What is calcitonin regulated by

Answer 16

Blood Ca2+ levels (independent of pituitary)

Question 17

What is calcitonin produced by

Answer 17

Parafollicular C cells

Question 18

What do the 3 veins of the thyroid gland branch off of

Answer 18

Superior vena cava and internal jugular vein

Question 19

What are the 3 veins of the thyroid gland

Answer 19

Superior, middle and inferior thyroid veins

Question 20

What are the 2 (or 3) arteries that supply the thyroid gland

Answer 20

Superior and inferior thyroid artery

Some have a third one called thyroidea ima

Question 21

What is thyroid cancer mainly an adenocarcinoma of

Answer 21

Follicular cells

Question 22

What is the cause of a goitre

Answer 22

Overactive thyroid

Question 23

Normally, how many parathyroid glands are there

Answer 23

4

Question 24

Where do the parathyroid glands come from

Answer 24

third and fourth pharyngeal arches

Question 25

What do the parathyroid glands secrete and what is this involved in

Answer 25

Parathyroid hormone -Involved in calcium homeostasis (raises calcium)

Question 26

How does parathyroid hormone raise serum Ca2+

Answer 26

Increase absorption in gut Act on kidney to prevent too much loss in urine Increase osteoclast activity (breakdown of bone) which releases Ca2+ into the blood

Question 27

What is hyperparathyroidism and what are the cause

Answer 27

Too much calcium in blood because parathyroid glands are too active - Tumour - KIdney failure

Question 28

If you need to remove parathyroid glands, what must you be careful not to damage

Answer 28

Thyroid and recurrent laryngeal nerves

Question 29

What is the secretory cell of the parathyroid gland

Answer 29

Pale chief cell