Download Pharyngeal Arches

EMBRYOLOGY:
PHARYNGEAL ARCHES
This diagram shows the development of pharyngeal arches
 At what stage of development do these structures appear?
 Why were these structures called branchial arches initially?
 How many pharyngeal arches develop in an embryo?
 Which pharyngeal arch does not give rise to any derivatives?
 List the three components which make up the pharyngeal arches.
 What does each component form?
 Which two structures contribute towards the formation of the first pharyngeal
arch?
 Which pharyngeal arches are responsible for the formation of the three bony
ossicles of the ear?
This diagram shows the development of the pharyngeal
pouches
 What do each of the pouches form?
 What does the tubotympanic recess contribute to?
This diagram shows the embryonic development of the tongue
 At what stage of development does the tongue develop?
 From which pharyngeal arch does the anterior two-thirds of the tongue develop?
 Which pharyngeal arches are responsible for the formation of the posterior third of
the tongue?
 Identify the abnormality depicted in the two pictures.
 Identify the abnormality depicted in the two pictures.
This diagram shows the formation of the thyroid
 From which germ layer does the thyroid gland derive?
 Where does the thyroid gland originate?
 When does the thyroid gland become functional?
This diagram shows the migratory pathway of the thyroid gland
from foramen cecum
 Describe this pathway.
This diagram shows the formation of thyroglossal cysts
 What results in the formation of these cysts?
 At what level in the neck region are these cysts commonly found?
Short essay questions
 Describe the embryonic development of the tongue.
(8 marks)
 Describe the embryonic development of the thyroid gland.
(5 marks)
Multiple choice questions
 Cartilage of the second pharyngeal arch
a.
b.
c.
d.
e.

Is known as Meckel’s cartilage.
Gives rise to the stapes of the ear.
Gives rise to the styloid process of the temporal bone.
Gives rise to the malleus of the ear.
Is also known as hyoid arch cartilage.
With regards to the third pharyngeal pouch
a.
b.
c.
d.
e.
The ventral wing forms the thymus.
The dorsal wing forms the superior parathyroid gland.
It gives rise to the ultimobranchial body.
It gives rise to the palatine tonsil.
It differentiates into the tubotympanic recess.
Match the embryonic structures in column A with their
frontrunners in column B
COLUMN A
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
Meckel’s cartilage
Second pharyngeal arch
Second pharyngeal pouch
First pharyngeal groove
First pharyngeal pouch
Intra embryonic mesoderm
Lateral lingual swellings
Third pharyngeal pouch
Copula
Ultimobranchial body
COLUMN B
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
Tubotympanic recess
External auditory meatus
Incus and malleus
Stapes
Palatine tonsil
Parafollicular cells
Inferior parathyroid gland
Posterior third of the tongue
Skeletal muscles
Body of tongue