Embryology

Question 1

During the 4th embryonic development, the tongue appears in the form of two lingual swellings and one medial swelling, the so-called:

Answer 1

Tuberculum impar

Question 2

Cartilages of 1st and 2nd arches are derived from

Answer 2

Neural crest cells

Question 3

Cartilages of the fourth-sixth brachial arches are derived from

Answer 3

Mesoderm

Question 4

Developmental defect affects the derivatives of the first branchial arch. Exhibits micrognathia, malar, hypoplasia, deformity of the lower rim of the orbit and malformed external ear.

Answer 4

Mandibulofacial dysostosis

Question 5

Failure of fusion of which of the following will lead to cleft lip?

Answer 5

Maxillary process; medial nasal process

Question 6

The first portion of the face to form after a he creation of the stomodeum

Answer 6

Mandible

Question 7

Failure of fusion of palatine shelves will lead to

Answer 7

Cleft palate

Question 8

During the fourth week the of embryonic development, the first branchial arch divides to form:

Answer 8

Mandibular and maxillary processes or also called as max and man prominences

Question 9

It is a faint ridge in the midline that on the surface of the bony mandible where the mandible is formed by the fusion of the mandibular processes

Answer 9

Mandibular symphysis

Question 10

The second branchial arch gives rise to the:

Answer 10

Palatine tonsil

Question 11

1st pharyngeal pouch gives rise to:

Answer 11

Formation of tympanic membrane, auditory tubes tympanic cavity, mastoid antrum

Question 12

3rd pharyngeal pouch gives rise to:

Answer 12

Inferior parathyroid glands (from the dorsal part) and
Thymus gland (ventral)

Question 13

3rd pharyngeal arch gives rise to:

Answer 13

Superior parathyroid glands (dorsal)

Question 14

5th pharyngeal pouch gives rise to:

Answer 14

Ultimobranchial bodies ( gives rise to C cells of the thyroid)

Question 15

C cells of the thyroid is responsible to secreting:

Answer 15

Calcitonin

Question 16

1st branchial CLEFT forms the

Answer 16

External auditory meatus

Question 17

Congenital malformation caused by underdevelopment of 4th and 5th branchial pouches leading to absence or hypoplasia or the parathyroid glands. The patients usually have congenital heart defects and compromised immunity

Answer 17

Digeorge syndrome

Question 18

The thyroid gland is first identifiable during the fourth week of gestation, beginning as an endodermal invagination of the tongue at the site of:

Answer 18

Foramen cecum

Question 19

The primary palate or median palatal process is formed by the merging of the frontonasal process with which other processes?

Answer 19

Medial nasal process

Question 20

Completion of the palate is during:

Answer 20

12th week of prenatal development

Question 21

The nasal cavities are formed from what embryonic structure?

Answer 21

Nasal pits

Question 22

The following are neural crest cells derivatives:

Answer 22

Melanocytes
Dorsal root ganglia
Adrenal medulla
Autonomic ganglia
Schwann cells
Sensory ganglia of cranial nerves