1.2 The Thyroid and Parathyroid Gland

Question 1

Where is the Thyroid Gland located?

Answer 1

In the Neck:

1. Anterior to the Trachea
2. Inferior to the Larynx

Question 2

Between which Vertebral Levels can the Thyroid Cland be found?

Answer 2

C5 to T1

Question 3

Where can the Thyroid Gland be found between?

Answer 3

1. The Cricoid Cartilage

2. The 6th Tracheal Ring

Question 4

What are the Parts of the Thyroid Gland?

Answer 4

1. The Left Lobe
2. The Right Lobe
3. The Isthmus

Question 5

What does the Isthmus do?

Answer 5

Connects the Left and Right Lobe of the Thyroid

Question 6

Which Tracheal Ring does the Isthmus lie opposite to?

Answer 6

The 2nd to the 3rd Tracheal Rings

Question 7

What are the 3 Strap Muscles which overlie the Thyroid?

Answer 7

1. Sternohyoid
2. Sternothyroid
3. Omohyoid

Question 8

What are the 2 Nerves which supply the Muscles of the Vocal Cord?

Answer 8

1. The Superior Laryngeal Nerve

2. The Recurrent Laryngeal Nerve

Question 9

Where does the Superior Laryngeal Nerve run?

Answer 9

From an inferior Ganglion of the Vagus Nerve, Lateral to the Thyroid and then enters into the Thyroid by the Cricoid Cartilage

Question 10

Where does the Recurrent Larngeal Nerve run?

Answer 10

From inferior to the Thyroid (around the level of the Heart), up to the Thyroid between the Trachea and the Oesophagus

Question 11

What Arteries supply the Thyroid?

Answer 11

1. The Superior Thyroid Artery

2. The Inferior Thyroid Artery

Question 12

Where does the Superior Thyroid Artery arise from?

Answer 12

The External Carotid Artery

Question 13

Where does the Inferior Thyroid Artery arise from?

Answer 13

The Thyrocervical Trunk (A Branch of the Subclavian Artery)

Question 14

What Veins drain the Thyroid?

Answer 14

1. The Superior Thyroid Vein
2. The Middle Thyroid Vein
3. The Inferior Thyroid Vein

Question 15

Into which vein does the Superior Thyroid Vein drain?

Answer 15

The Internal Jugular Vein

Question 16

Into which vein does the Middle Thyroid Vein drain?

Answer 16

The Internal Jugular Vein

Question 17

Into which vein does the Inferior Thyroid Vein drain?

Answer 17

The Left Braciocephalic Vein

Question 18

Where does the Lymph from the Thyroid Gland drain to?

Answer 18

The Deep Cervical Lymph Nodes

Question 19

Where are the Hormones of the Thyroid Gland stored?

Answer 19

In Cavities surrounded by Secretory Cells

Question 20

What is the name of the Cavity and Secretory Cells?

Answer 20

The Follicle

Question 21

What happens within the Cavity of the Follicle?

Answer 21

The Hormone created is bound to a Glycoprotein

Question 22

What is the new name for the Hormone bound to the Glycoprotein?

Answer 22

The Colloid

Question 23

What happens during secretion of the Hormone?

Answer 23

IT is re-absorbed from the Cavity and released into the surrounding Interstitial Space

Question 24

What separated the Follicles?

Answer 24

Fibrous Septae

Question 25

What type of Cells line the Follicle?

Answer 25

Follicular Cells

Question 26

What is the Cell Type of Follicular Cells?

Answer 26

Simple Columnar Epithelium

Question 27

What colour does the Colloid stain?

Answer 27

Pink

Question 28

What secretes Calcitonin?

Answer 28

Parafollicular (C) Cells

Question 29

What is the action of Calcitonin?

Answer 29

Calcitonin reduces Serum Calcium Levels

Question 30

How does Calcitonin reduce Serum Calcium Levels?

Answer 30

1. Inhibiting the Activity of Osteoclasts | 2. Decrease Calcium re-absorption at the Kidneys

Question 31

What Hormones does the Thyroid Gland secrete?

Answer 31

T3 - Triiodothyronine | T4 - Thyroxine

Question 32

Where do the Parathyroid Hormones lie?

Answer 32

The Medial part of the Posterior Surface of Each Thyroid Lobe

Question 33

How is the Parathyroid Gland related to the Thyroid Gland?

Answer 33

It is External to (and separated by) the thin Thyroid Fibrous Capsule

Question 34

How many Parathyroid Hormones do most people have?

Answer 34

4

Question 35

What is the Arterial Supply to the Superior and Inferior Parathyroid Glands?

Answer 35

The Inferior Thyroid Arteries

Question 36

Which Vein drains the Parathyroid Glands?

Answer 36

The Veins draining the (Superior and Middle) Thyroid to the Internal Jugular Vein

Question 37

What are the 2 Cell Types present in the Parathyroid Gland?

Answer 37

1. The Chief Cells | 2. The Oxyphil Cells

Question 38

Are there more of fewer Chief Cells than Oxyphil Cells?

Answer 38

More

Question 39

Do the Chief Cells stain Darker or Lighter than the Oxyphil Cells?

Answer 39

Darker

Question 40

Are the Chief Cells Larger or Smaller than the Oxyphil Cells?

Answer 40

Smaller

Question 41

What is the function of the Parathyroid Chief Cells?

Answer 41

To Secrete Parathyroid Hormone

Question 42

What is the Parathyroid Hormone associated with?

Answer 42

Calcium Homeostasis

Question 43

How does the Parathyroid Hormone influence Calcium Homeostasis?

Answer 43

It increases the action of Osteoclasts (Bone Re-modelling) which increases the Plasma Calcium Levels

Question 44

What is the function of the Parathyroid Oxyphil Cells?

Answer 44

There is no known function