Pituitary, Thyroid + Tongue Embryology

Question 1

What is the relevance of the pituitary, thyroid and tongue?

Answer 1

All midline structures

Question 2

What does the anterior pituitary develop from?

Answer 2

Rathke’s pouch

Question 3

What is Rathke’s pouch?

Answer 3

Outpocketing of the ectoderm of the stomatodeum

Question 4

What forms the pituitary stalk?

Answer 4

Infundibulum

Question 5

What does the posterior pituitary develop from?

Answer 5

Infundibulum

Question 6

What is the infundibulum?

Answer 6

Downward growth of the forebrain

Question 7

When does the pituitary start developing?

Answer 7

Week 3

Question 8

How does the pituitary develop?

Answer 8

Rathke’s pouch appears and extends up to the infundibulum

By week 8, detaches from oral cavity and attaches to infundibulum

Question 9

When does the tongue start to develop?

Answer 9

Week 4

Question 10

What is the tongue derived from?

Answer 10

Mucosa - pharyngeal arches 1-4

Musculature - occipital somites

Question 11

What is the first stage of tongue development?

Answer 11

Formation of ligual and medial swellings

Question 12

How many lingual swellings are there?

Answer 12

2

Question 13

Where are the lingual swellings derived from?

Answer 13

1st pharyngeal arch

Question 14

What do the lingual swellings form?

Answer 14

Mucosa of anterior 2/3 tongue

Question 15

How many medial swellings are there?

Answer 15

3

Question 16

What is the first medial swelling/

Answer 16

Tuberculum impar

Question 17

Where is the tuberculum impar derived from?

Answer 17

1st pharyngeal arch

Question 18

What does the tuberculum impar form?

Answer 18

Mucosa of anterior 2/3 tongue

Question 19

What is the second medial swelling?

Answer 19

Cupola

Question 20

Where is the cupola derived from?

Answer 20

2nd, 3rd, 4th pharyngeal arches

Question 21

What does the cupola form?

Answer 21

Mucosa of posterior 1/3 tongue

Question 22

What is the third medial swelling?

Answer 22

Epiglottal swelling

Question 23

What is the epiglottal swelling derived from?

Answer 23

4th pharyngeal arch

Question 24

What does the epiglottal swelling form?

Answer 24

Epiglottis

Question 25

How does the mucosa of the tongue form?

Answer 25

Lateral lingual swellings overgrow the tuberculum impar to form anterior 2/3 tongue Cupola fuses with anterior tongue forming a groove called the terminal sulcus Centre of terminal sulcus is the foramen cecum Tongue is initially tethered to floor of the oral cavity but apoptosis leaves on the lingual frenulum

Question 26

How does the musculature of the tongue form?

Answer 26

Somites migrate from neck to give the musculature

Question 27

Where does the thyroid begin development?

Answer 27

Foramen cecum

Question 28

How does the thyroid develop?

Answer 28

Proliferation of endodermal cells between cupola and tuberculum impar Cell proliferation bifurcates and descends into neck

Question 29

What is formed by the descent of the thyroid?

Answer 29

Thyroglossal duct

Question 30

When should the thyroglossal duct regress?

Answer 30

Week 10