Thyroid, Parathyroid and Salivary Glands

Question 1

What connects the left and right lobes of the thyroid gland

Answer 1

Isthmus

Question 2

What is the level of the thyroid gland

Answer 2

C5-T1

Question 3

What are the things that lie around the thyroid gland

Answer 3

Anteriorly:

• Loose sheath formed by pretracheal fascia
• Sternohyoid and Sternothyroid

Posteriorly:
-Cricoid cartilage and upper 2-3 tracheal rings

Posterolaterally:
-Carotid sheaths and content

Question 4

what type of gland is the thyroid gland

Answer 4

ductless endocrine gland - secretes directly into blood

Question 5

What does the thyroid gland secrete

Answer 5

Thyroid hormone

Calcitonin

Question 6

Where does the vascularity of the thyroid gland lie?

Answer 6

within the loose sheath formed by the pretracheal fascia

on top of the fibrous capsule

Question 7

What is the arterial supply of the thyroid gland

Answer 7

inferior thyroid artery

superior thyroid artery

Question 8

From where does the inferior thyroid artery arise

Answer 8

it is the largest branch of the thyrocervical trunk

Question 9

Explain the course of the inferior thyroid artery

Answer 9

ascends posterior to carotid sheath

Question 10

What part of the thyroid gland does the inferior thyroid artery supply

Answer 10

Inferior pole

Posterior Surface

Question 11

From where does the Superior thyroid artery arise

Answer 11

1st branch of external carotid

Question 12

What part of the thyroid gland does the superior thyroid artery supply

Answer 12

First divides into anterior and posterior branches

Superior pole
Anterior surface of gland

Question 13

What is the plexus that drains the thyroid gland made up of

Answer 13

Superior thyroid vein –> IJV
Middle thyroid vein –> IJV
Inferior thyroid vein –> thyroid impar of Brachiocephalic vein

Question 14

What is the lymphatic drainage of the Thyroid gland

Answer 14

Prelaryngeal Lymph Nodes —> Superior Cervical LN

Pretracheal Lymph Nodes —> Inferior Deep Cervical LN

Paratracheal Lymph Nodes —> Inferior Deep Cervical LN

Lymphatic vessels along Superior Thyroid Vein drain into:

• Inferior Deep Cervical LN
• Brachiocephalic LN
• Thoracic Duct

Question 15

Explain the parasympathetic innervation of the thyroid gland

Answer 15

Vagus Nerve via:

• Superior Laryngeal Nerve
• Recurrent Laryngeal Nerve

Question 16

Explain the sympathetic innervation of the thyroid gland

Answer 16

(Superior, Middle and Inferior) Cervical Sympathetic Ganglia

Via

• Cardiac para-arterial plexuses
• Superior thyroid para-arterial plexuses
• Inferior thyroid para-arterial plexuses

GIVE VASOMOTOR INNERVATION - CAUSE CONSTRICTION OF BLOOD VESSELS

Question 17

What is endocrine secretion of the thyroid hormone regulated by?

Answer 17

Not directly stimulated by the ANS

However, regulated by Pituitary Hormones

Question 18

What is the location of the Parathyroid Glands

Answer 18

On posterior surface of thyroid
External to Thyroid Fibrous Capsule
Within sheath formed by Pretracheal fascia

Superior Parathyroid Glands:
1cm above piercing of Inf. Thyroid A.

Inferior Parathyroid Glands:
1cm below piercing of Inf. Thyroid A.

Question 19

What do the parathyroid glands secrete?

Answer 19

PTH

Regulates calcium and Phosphorus metabolism
Targets skeleton, kidneys and intestines

Question 20

What is the arterial supply of the Parathyroid Gland

Answer 20

Mostly:
-Branches of Inf. Thyroid A.

Also:

• Sup. Thyroid A.
• Thyroid Ima A.
• Laryngeal A.
• Tracheal A.
• Oesophageal A.

Question 21

What is the venous drainage of the Parathyroid Gland

Answer 21

Thyroid Plexus of veins (of Thyroid and Trachea)

Question 22

What is the lymphatic drainage of the Parathyroid Gland

Answer 22

Deep Cervical LN
Paratracheal LN

RUN WITH THE THYROID LYMPHATIC VESSELS

Question 23

What is the innervation of the Parathyroid Gland

Answer 23

—Vasomotor—

Thyroid branches of the CERVICAL SYMPATHETIC GANGLIA

Question 24

Name the salivary glands

Answer 24

3 main pairs:

• Submandibular
• Sublingual
• Parotid

Accessory:

• Lips
• Cheeks
• Palate
• Tongue

Question 25

Explain the position of the Submandibular Gland

Answer 25

Partly superior and partly inferior - to the posterior half of the body of the mandible Partly superficial and partly deep to myolohyoid muscle

Question 26

Explain the course of the Submandibular Duct

Answer 26

5cm long between Mylohyoid and Hyoglossus As it passes anteriorly, the Lingual N. loops under it Opens on 3 sublingual papillae (on either side of the tongue frenulum)

Question 27

What is the Blood Supply to the Submandibular Glands?

Answer 27

``` Submental Artery (Branch of Facial A.) Submental Vein ```

Question 28

What is the Parasympathetic innervation to the submandibular glands

Answer 28

---secretomotor--- Presynaptic parasympathetic fibres from FACIAL N. via CHORDA TYMPANI N. to the LINGUAL N. Lingual N. synapses with postsynaptic nerve fibres that supply the gland

Question 29

What is the Sympathetic innervation to the submandibular glands

Answer 29

Fibres from the SUPERIOR CERVICAL GANGLION

Question 30

What is the lymphatic drainage of the Submandibular Glands

Answer 30

Lymphatic vessels of glands end in the deep cervical LNs - particularly the juglo-omohyoid node

Question 31

What is the structure of the Sublingual Glands

Answer 31

Bilateral Almond Shaped Glands | Unite to form horse-shoe shape mass around frenulum.

Question 32

What is the blood supply to the Sublingual Glands

Answer 32

Submental A. (br. of Facial A.) and V Sublingual A (br. of Lingual A.) and V.

Question 33

What is the innervation of the Sublingual Glands

Answer 33

Accompanies that of the submandibular gland ---secretomotor--- -----PARASYMPATHETIC---- Presynaptic parasympathetic fibres from FACIAL N. via CHORDA TYMPANI N. to the LINGUAL N. Lingual N. synapses with postsynaptic nerve fibres that supply the gland ----SYMPATHETIC---- Fibres from the SUPERIOR CERVICAL GANGLION

Question 34

What are the borders of the Parotid Region?

Answer 34

Superior: -Zygomatic Arch Posterior - Ear - Anterior border of SCM Medial: -Ramus of Mandible Anterior: -Medial border of Masseter Inferior: -Angle of Mandible

Question 35

What is the content of the Parotid Region?

Answer 35

``` Parotid gland and duct Parotid plexus of Facial N. Ext. Carotid A. Retromandibular V. Masseter ```

Question 36

What is the Parotid Gland surrounded by?

Answer 36

Parotid Sheath A fibrous capsule derived from Investing Fascia

Question 37

What is the location of the Parotid Bed?

Answer 37

Anterior and Inferior to External Acoustic Meatus Between Mastoid Process and Ramus of Mandible Apex is posterior to the angle of the Mandible Base is related to the Zygomatic Arch Laterally, it is flat and subcutaneous

Question 38

What is the course of the Parotid Duct

Answer 38

Runs horizontally from the Anterior edge of the gland Turns medially at the edge of the Masseter Pierces Buccinator Opens in Oral Vestibule opposite the 2nd Maxillary Molar

Question 39

What is embedded in the Parotid Gland

Answer 39

Parotid Plexus of Facial N. Retromandibular V. External Carotid A.

Question 40

What is the blood supply to the Parotid Glands

Answer 40

Posterior Auricular A Superficial Temporal A. (br. of Ext Carotid)

Question 41

What is the venous drainage of the Parotid Glands

Answer 41

Retromandibular v

Question 42

What is the parasympathetic innervation of the Parotid Glands

Answer 42

GLOSSOPHARANGEAL N - Presynaptic Parasympathetic Fibres to OTIC GANGLION Postsynaptic parasympathetic fibres are conveyed from here to Parotid Gland via the AURICULOTEMPORAL N.

Question 43

What is the sympathetic innervation of the Parotid Glands

Answer 43

---vasomotor--- Cervical Ganglia ---> External Carotid Nerve Plexus

Question 44

What is the sensory innervation of the Parotid Glands

Answer 44

Auriculotemporal N Great Auricular N (br. of Cervical Plexus: C2-C3) Innervates Parotid Sheath and Overlying Skin