Embryology

Question 1

What are the pharyngeal arches?

Answer 1

Series of arches which develop around the future mouth and pharynx

Question 2

What structures develop from the pharyngeal arches?

Answer 2

Face and neck

Question 3

How many branchial arches are there in humans?

Answer 3

5 - 6 start to develop but arch number 5 disappears

Question 4

What lines the outside of the branchial arches?

Answer 4

Ectoderm

Question 5

Ectoderm also forms

Answer 5

the clefts in between the pharyngeal arches

Question 6

Mesoderm lines and forms

Answer 6

lines the middle of the pharyngeal arches and forms cartilage and muscles

Question 7

Endoderm lines and forms

Answer 7

lines inside of pharyngeal arches and forms pouches in between the arches

Question 8

What arches does the digastric muscle develop from?

Answer 8

First (anterior belly) and second (posterior belly) pharyngeal arches

Question 9

Other important structures that develop from the pharyngeal arches

Answer 9

Tongue
Thyroid gland
Parathyroid gland
Part of pituitary gland

Question 10

From what processes does the face develop?

Answer 10

Frontonasal
Two maxillary processes
Two mandibular processes

Question 11

How is the nostril formed?

Answer 11

Ectodermal thickening, pushes inwards to form nasal pit which develops into the nostril

Question 12

What happens in stage 1 of development of the palate?

Answer 12

Medial nasal process grows downwards and forms philtrum

Question 13

What happens in stage 2 of the development of the palate?

Answer 13

Two palatine shelves grow inwards from the maxillary processes

Question 14

What happens in stage 3 of development of the palate?

Answer 14

Palatine shelves meet in the midline to form secondary palate

Question 15

How are the flat bones of the skull formed?

Answer 15

Membranous ossification

Question 16

How are the irregular bones of the base of the skull formed?

Answer 16

Endochondral ossification

Question 17

How is the viscerocranium formed?

Answer 17

Partly from pharyngeal arches and partly from sensory capsules

Question 18

Mesenchyme is derived from

Answer 18

mesoderm that lies above the surface of the developing brain

Question 19

Why are the sutures between the skull bones soft at birth?

Answer 19

Allows deformation during passage through the birth canal

Question 20

What nerve supplies the first pharyngeal arch?

Answer 20

Mandibular branch of trigeminal

Question 21

What nerve supplies the second pharyngeal arch?

Answer 21

Facial nerve

Question 22

What nerve supplies the third pharyngeal arch?

Answer 22

Glossopharyngeal

Question 23

What nerve supplies the fourth pharyngeal arch?

Answer 23

Superior laryngeal branch of vagus

Question 24

What nerve supplies the sixth pharyngeal nerve?

Answer 24

Recurrent laryngeal

Question 25

What is craniosynostosis?

Answer 25

Premature fusion of the cranial bones

Question 26

Sensory capsules are derived from

Answer 26

mesoderm of somites in the head and neck region

Question 27

What is the function of sensory capsules?

Answer 27

Preform cartilage and ossify to form bones around the sense organs and form part of the base of skull and viscerocranium

Question 28

To form the base of the skull, bone is laid down by

Answer 28

endochondral ossification

Question 29

Treacher-Collins syndrome is a result of an abnormality of which pharyngeal arch?

Answer 29

First