L1: Embryology

Question 1

What happen by the 3rd week of post fertilization?

Answer 1

The embryonic disc has differentiated into 3 germ layers

Question 2

What are the germ layers?

Answer 2

• ectoderm
• mesoderm
  -endoderm

Question 3

What are the 2 important structures involved in the development of nose and face?

Answer 3

• Pharyngeal arches
• Neural crest cells

Question 4

How many pharyngeal arches can we find?

Answer 4

6 pharyngeal arches

Question 5

when is the pharyngeal arches being form?

Answer 5

At the 4th week

Question 6

Where does pharyngeal arch come from (Origin)?

Answer 6

Out-pocketing of the mesoderm on both side of pharynx

Question 7

Each pharyngeal arch will have a branch of __________, a __________ and an associated __________ .

Answer 7

Each pharyngeal arch will have a branch of artery, a cranial nerve, and an associated cartilage bar.

Question 8

Another name for pharyngeal arch

Answer 8

Brancial arch

Question 9

1st branchial arch (1st pharyngeal arch) is also known as ?

Answer 9

Mandibular arch

Question 10

Innervation of 1st pharyngeal arch (branchial arch)?

Answer 10

Trigeminal nerve (V)

Question 11

1st pharyngeal arch divides into what?

Answer 11

Maxillary (double) process
Mandibular (double) process

Question 12

1st pharyngeal arch muscles

Answer 12

Masticatory muscles
(Temporal)
(Pterygoid)
(Anterior belly of diagastric)
(Mylohioid)
(Malleus muscle)

Question 13

Cartilage of 1st pharyngeal arch?

Answer 13

Meckel’s cartilage

Question 14

Meckel’s cartilage involves in ossification of mandible (True or false)?

Answer 14

False

Question 15

2nd pharyngeal arch (branchial arch) is also known as?

Answer 15

Hyoid arch

Question 16

Innervation of 2nd pharyngeal arch?

Answer 16

Facial nerve (VII)

Question 17

Derivatives of the 2nd pharyngeal arch

Answer 17

Hyoid, styled apophysis, and styloid ligament

Question 18

Muscles of 2nd pharyngeal arch?

Answer 18

Facial expression muscles

Question 19

Muscles of 2nd pharyngeal arch

Answer 19

Facial expression muscle

Question 20

Innervation of 3rd pharyngeal (branchial) arch?

Answer 20

Glossopharyngeal (IX)

Question 21

Muscles of 3rd pharyngeal (branchial) arch?

Answer 21

Stylopharyngeus muscle

Question 22

Innervation of 4th pharyngeal (branchial) arch?

Answer 22

Vagus nerve (X)

Question 23

Muscles of 4th pharyngeal (branchial) arch?

Answer 23

Soft palatal muscle (except: tensor cell palatini from the 1st)
Pharyngeal muscle (except stylopharyngess from the 3rd )
Cricothyroid muscle
Cricopharyngeus muscle

Question 24

Innervation of 6th pharyngeal arch?

Answer 24

Vagus nerve (X)

Question 25

Muscles of 6th pharyngeal (branchial) arch?

Answer 25

Intrinsic muscle of larynx (except: cricothyroid muscle from the 4th) Upper (skeletal) muscles of esophagus

Question 26

How many pharyngeal arches we will have by the end of development

Answer 26

5 pharyngeal arches in total (the 5th branchial arch disappears)

Question 27

Oral cavity forms between what weeks?

Answer 27

3rd week to 5th week

Question 28

What happen between 3rd and 5th week?

Answer 28

Oral cavity formation 3rd week: orropharyngeal membrane (buccopharyngeal membrane) is firstly seen at the site of future face (between heart and primordial of the brain) 4th week: breakdown down of oropharyngeal membrane forming the opening of future oral cavity (primitive mouth or stomodeum) and the foregut

Question 29

How is the buccopharyngeal membrane and the pharyngeal arches in 25 day old embryo?

Answer 29

Buccopharyngeal membrane remains intact No pharyngeal arches yet

Question 30

How is the buccopharyngeal membrane and the pharyngeal arches in 35 day old embryo?

Answer 30

Buccopharyngeal membrane break down, mouth now open to the esophagus Pharyngeal arches and pouches nicely formed

Question 31

When does forebrain starts to develop?

Answer 31

4th week

Question 32

When does facial development begin?

Answer 32

4th week - 7th week

Question 33

What happen at the 4th week during facial development (What fusion of process are involved) ?

Answer 33

Frontonsal process Nasal placodes Maxillary process Mandibular process

Question 34

What happen during the 5th week of facial development (what fusion of process are involved)?

Answer 34

Nasopalatine process Medial nasal process Small part maxilla Gum Primary palate

Question 35

During the 4th week in the process of facial develoment what does the frontonasal process form?

Answer 35

Skull nose and upper lip

Question 36

During the 4th week in the process of facial develoment what does the nasal placodes form?

Answer 36

Nasal pit

Question 37

During the 4th week in the process of facial develoment what does the maxillary process form into?

Answer 37

Lateral portion of upper lip Maxilla Secondary palate

Question 38

During the 4th week in the process of facial develoment what does the mandibular process from into?

Answer 38

Lower lip Jaw

Question 39

During the 5th week in the process of facial develoment what does nasopalatine process from into?

Answer 39

Nasal wing

Question 40

During the 5th week in the process of facial develoment what does the medial nasal process form into?

Answer 40

Middle potion of the nose (bridge and septum) Groove of upper lip Small part of maxilla Gum Primary palate

Question 41

Origin of primary palate

Answer 41

Medial nasal process

Question 42

Origin of secondary palate

Answer 42

Maxillary process - Lateral palatine process of maxilla

Question 43

Origin of anterior 2/3 of tongue

Answer 43

1st pharyngeal arch (mandibular arch)

Question 44

Tongue and mandible has same / different origin and develop at the same / different time.

Answer 44

STongue and mandible has same origin and develop at the same time.

Question 45

Origin of posterior 1/3 of tongue

Answer 45

2nd, 3rd, and 4th pharyngeal arch give rise to hypobranchial eminence in which will develop into posterior 1/3 of the tongue

Question 46

Upper border of oral cavity

Answer 46

Hard palate

Question 47

Inferior border of oral cavity

Answer 47

Tongue and floor of the mouth

Question 48

Posterior border of the oral cavity

Answer 48

Isthmus of the fauces and palatine tonsil