Anatomy- The THYROID GLAND

Question 1

At level in the Neck is the THYROID Gland Situated?

Answer 1

C5 to T1

Question 2

What are the Main parts of the THYROID gland?

Answer 2

• Right and Left LOBES, connected by the ISTHMUS

Question 3

Describe the Fascia of the Thyroid?

Answer 3

PRETRACHEAL FASCIA

Question 4

What is the Pretracheal Fascia? What are its 2 parts?

Answer 4

Part of the DEEP CERVICAL FASCIA
Composed of PARIETAL and VISCERAL component

Question 5

What is Contained within the PRETRACHEAL FASCIA?

Answer 5

Muscles- Sternothyroid, Omothyroid, Omohyoid
Organs- Thyroid, Trachea, Pharynx and Larynx

Question 6

What are the RELATIONS of the Thyroid?

Answer 6

ANTERIOR- Pretracheal Fascia, Strap Muscles, Sternocleidomastoid Muscles

LATERAL- Carotid Sheath (Common Carotid Artery, Vagus Nerve, Internal Jugular Vein)

POSTERIOR- Larynx,Trachea Pharynx and Oesophagus

Question 7

Where is the THYROID ISTHMUS located in relation to the Trachea?

Answer 7

The Isthmus overlies the 2nd and 3rd Rings of the Trachea

Question 8

What is the ARTERIAL SUPPLY of the Thyroid?

Answer 8

Superior Thyroid Artery
Inferior Thyroid Artery
Thyroid Ima Artery

Question 9

Where does the SUPERIOR THYROID ARTERY come from?

Answer 9

External Carotid Artery

(Passes to the Upper pole of the Thyroid)

Question 10

Where does the INFERIOR THYROID ARTERY come from?

Answer 10

Subclavian Artery

(Passes behind the Carotid Sheath to the Back of the Thyroid)

Question 11

Where does the THYROID IMA ARTERY come from?

Answer 11

Aortic Arch or Brachiocephalic Artery

(INCONSISTANT ARTERY)

Question 12

What is the VENOUS DRAINAGE of the Thyroid?

Answer 12

Superior Thyroid Vein
Middle Thyroid Vein
Inferior Thyroid Vein

Question 13

Where does the Superior Thyroid Vein drain?

Answer 13

Internal Jugular Vein

Question 14

Where does the Middle Thyroid Vein drain?

Answer 14

Internal Jugular Vein

Question 15

Where does the Inferior Thyroid Vein Drain?

Answer 15

Brachiocephalic Veins

Question 16

What important Nerves are closely related to the Thyroid?

Answer 16

1) Recurrent Laryngeal Nerve

2) External Branch of the Superior Laryngeal Nerve

Question 17

Where does the Recurrent Laryngeal Nerve lie in relation to the Thyroid?

Answer 17

Recurrent Laryngeal Nerve lies in Tracheoesophgeal Groove between the Trachea and Oesophagus

Question 18

TRACHEOESOPHAGEAL GROOVE

Answer 18

Question 19

What is the Nerve Supply of the THYROID?

Answer 19

Sympathetic Nerve

• Nerves DO NOT control hormone secretion from the Thyroid

Question 20

What is Berry’s Ligament?

Answer 20

AKA Suspensory Thyroid Ligament
Attaches the Thyroid to the Trachea posteriorly

Question 21

Berry’s Ligament

Answer 21

Question 22

Relations of the THYROID GLAND

Answer 22

Question 23

Describe the EMBRYOLOGY of the Thyroid Gland

Answer 23

The Thyroid develops from the THYROGLOSSAL DUCT at the base of the FETAL TONGUE

THYROGLOSSAL DUCT descends into the Neck

Question 24

THYROGLOASSAL DUCT

Answer 24

Question 25

What is the FORAMEN CAECUM of the Tongue?

Answer 25

Groove that marks the boundary between the posterior 1/3 and anterior 2/3 of the Tongue REMNANT OF THE THYROGLOSSAL DUCT

Question 26

FORAMEN CAECUM- TONGUE

Answer 26

Question 27

What is a LINGUAL THYROID?

Answer 27

- Congenital Condition - Ectopic Thyroid Tissue at the Base of the Tongue - Results from failure of the Thyroglossal duct to descent into the neck -May present with airway obstruction and dysphagia

Question 28

LINGUAL THYROID

Answer 28

Question 29

Describe the HISTOLOGY of the THYROID GLAND?

Answer 29

- THYROID FOLLICLE: Functional Unit of the Thyroid Gland. Thyroid Follicles contain Colloid -THYROID LOBULES: Thyroid Capsule Extends into the Gland dividing it into lobules -PARAFOLLICULAR C CELLS: Cells secrete Calcitonin

Question 30

THYROID HISTOLOGY

Answer 30

Question 31

What is the FUNCTION of the THYROID FOLLICLE?

Answer 31

- Store THYROGLOBULIN

Question 32

What is THYROGLOBULIN?

Answer 32

- Glycoprotein -Produced by the Follicular cells - Pre-cursor for THYROID HORMONES (T3 and T4)

Question 33

What is the ACTION of CALCITONIN?

Answer 33

- Antagonist of PARATHYROID HORMONE -REDUCES CALCIUM- Suppresses Oesteoclasts