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Flashcards in Development of tongue Deck (18)
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1

What marks the anterior 2/3 from the posterior 1/3 of the tongue?

Sulcus terminalis

2

What shape is the sulcus terminalis?

V shape

3

What is the point of the sulcus terminalis?

Foramen caecum

4

What embryonic tissue does the tongue develop from?

Parts of each of the pharyngeal arches

5

What is the structure of the developing tongue?

Lateral lingual swellings x2

Median lingual swellings x3

6

How are the lingual swellings of the developing tongue arrached?

Lateral lingual swellings are antero-lateral on each side

Median lingual swellings are posterior to the lateral lingual swellings and in the midline

7

What are the three median swellings?

Tuberculum impar

Cupola

Epiglottal swelling

8

Which pharyngeal arch do the lateral lingual swellings develop from?

1st pharyngeal arch

9

Which pharyngeal arch does the tuberculum impar develop from?

1st pharyngeal arch

10

Which pharyngeal arch does the cupola develop from?

2nd, 3rd and 4th pharyngeal arches from anterior to posterior

11

Which pharyngeal arch does the epiglottal swelling develop from?

4th pharyngeal arch

12

What happens to the lateral and medial swellings of the tongue as it develops?

Lateral lingual swellings overgrow tuberculum impar

The 3rd pharyngeal arch part overgrows the 2nd pharyngeal arch part of the cupola

13

What is the structure of the developed tongue?

Anterior 2/3 made up of lateral lingual swellings

Posterior 1/3 made up of 3rd and 4th pharyngeal arches

14

How does the lingual frenulum develop?

Degeneration of inferior surface of tongue
freeing it from the floor of the oral cavity

only the lingual frenulum remains

15

How does the development of the tongue explain the sensory innervation of the tongue?

Anterior 2/3 derived from 1st pharyngeal arch
general sensory innervation by CN5 trigeminal nerve

Posterior 1/3 from 3rd pharyngeal arch
sensory innervation by CN9 glossopharyngeal nerve

16

How do the muscles of the tongue develop?

Occipital somites
myogenic precursors migrate from here into developing tongue
develop into intrinsic and extrinsic muscles of tongue

17

Which nerve corresponds to the occipital somites?

CN12 hypoglossal nerve

18

How does the development of the muscles of the tongue explain the motor innervation of the tongue?

Myogenic precursors from occipital somites take their innervation with them
hence intrinsic and extrinsic muscles of tongue innervated by CN12 hypoglossal nerve