Head & Neck Embryology Flashcards
(86 cards)
1
Q
What are the components of the pharyngeal (brachial) apparatus?
A
- Pharyngeal arch
- Pharyngeal groove (clef)
- Pharyngeal pouch
- Pharyngeal membrane
2
Q
What cells are found in pharyngeal arches?
A
Neural crest cells
3
Q
Initially, pharyngeal arches are a core of ___ covered by ______
A
Initially, pharyngeal arches are a core of mesenchyme covered by ectoderm externally and endoderm internally
4
Q
What are the components of each pharyngeal arch?
A
- Artery
- Bone (cartilaginous rod)
- Muscle
- Nerve
5
Q
The artery of a pharyngeal arch is derived from…
A
truncus arteriosus
6
Q
Do pharyngeal arches 1, 2, and 3 develop together or separately?
A
Separately
7
Q
Cartilaginous portions of which pharyngeal arches will fuse?
A
Arches 4 and 6
8
Q
Which pharyngeal arch regresses and has no derivatives?
A
Arch 5
9
Q
What is included in the frontonasal prominence?
A
- Optic vesicles
- Forehead
- Stomodeum (primordial mouth)
- Nose (frontal and lateral nasal prominences)
10
Q
The first pharyngeal arch is also known as…
A
mandibular arch
11
Q
What is the bone/cartilage component of the first pharyngeal arch?
A
Meckel’s cartilage
12
Q
first arch
The maxillary prominence and mandibular prominence are from mesoderm around…
A
Meckel’s cartilage
13
Q
first arch
What will come of the maxillary prominence?
A
- Maxilla
- Zygomatic bone
- Squamous part of temporal bone
- Upper cheek regions and lip
14
Q
first arch
What will come of the mandibular prominence?
A
- Mandible
- Chin, lower lip, cheek regions
15
Q
first arch
What will come of the dorsal end?
A
- Malleus
- Incus
- Sphenomandibular ligament
16
Q
What are five muscular components of the first pharyngeal arch?
A
- Muscles of mastication
- Tensor veli palatini
- Tensor tympani
- Mylohyoid
- Anterior belly of digastric
17
Q
What is the nerve component of the first pharyngeal arch?
A
CN V trigeminal
18
Q
The second pharyngeal arch is also known as…
A
hyoid arch
19
Q
What is the bone/cartilage component of the second pharyngeal arch?
A
Reichert’s cartilage
20
Q
second arch
What will come of Reichert’s cartilage?
A
- Stapes
- Styloid process
- Stylohyoid ligament
- Lesser cornu and upper part of body of hyoid
21
Q
What are four muscular components of the second pharyngeal arch?
A
- Muscles of facial expression
- Stapedius
- Stylohyoid
- Posterior belly of digastric
22
Q
What is the nerve component of the second pharyngeal arch?
A
CN VII facial
23
Q
What would you call a persistent second pharyngeal groove or cervical sinus?
A
Branchial cyst
24
Q
When is a branchial cyst apparent?
A
Beginning in late childhood or early adulthood
25
How does a branchial cyst appear?
Painless swollen mass slowly enlarging inferior to angle of mandible and anterior to SCM
26
Which pharyngeal arch does not develop into adult structures?
Arch 5
27
What are the bone/cartilage components of the third pharyngeal arch?
* Thyroid cartilage
* Hyoid bone (greater cornu and part of body)
28
What is the muscular component of the third pharyngeal arch?
Stylopharyngeus
29
What is the nerve component of the third pharyngeal arch?
CN IX glossopharyngeal
30
What is the bone/cartilage component of the fourth and sixth pharyngeal arches?
Laryngeal cartilages (except epiglottis)
31
The epiglottis develops from...
hypopharyngeal eminence
32
What is the muscular component of the fourth and sixth pharyngeal arches?
Pharyngeal and laryngeal muscles:
* Cricothyroid
* Levator veli palatini
* Pharyngeal constrictor muscles
33
What is the nerve component of the fourth and sixth pharyngeal arches?
CN X vagus
4: superior laryngeal nerve
6: recurrent laryngeal nerve
34
The tympanic cavity, mastoid antrum, pharyngotympanic tube, and tympanic membrane are all derived from which pharyngeal apparatus pouch?
First pouch
35
The tonsillar fossa and palatine tonsils are derived from which pharyngeal apparatus pouch?
Second pouch
36
The inferior parathyroid glands and thymus are derived from which pharyngeal apparatus pouch?
Third pouch
37
The superior parathyroid glands and thyroid parafollicular cells are derived from which pharyngeal apparatus pouch?
Fourth pouch
38
#thyroid parafollicular cells
C-cells produce...
calcitonin
39
What comes of the pharyngeal apparatus first groove?
External auditory meatus
40
What comes of the pharyngeal apparatus grooves (besides the first)?
Lie in cervical sinus and are obliterated as neck develops or becomes branchial cyst
41
What happens to the pharyngeal apparatus grooves if they are not obliterated as the neck develops?
Branchial cyst
42
When is the tongue developed in utero?
End of week 4
43
In the development of the tongue, the first pharyngeal arch gives rise to...
median and lateral lingual swellings
44
The rostral tongue develops from...
hypopharyngeal eminence
45
Hypopharyngeal eminence (thus rostral tongue) is derivative of...
fourth pharyngeal arch
46
Rostral tongue is ___ to sulcus terminalis
posterior
47
What is the innervation of the tongue during development?
CN XII hypoglossal
48
When do taste buds develop in utero?
Weeks 11-13
49
When is primary growth of the face in utero?
Weeks 4-8
50
The frontonasal prominence includes...
* optic vesicles
* forehead
* stomodeum
* nose
51
The maxillary prominences include...
* lateral boundaries of stomodeum
* upper cheek regions and lip
52
The mandibular prominences include...
* caudal boundary of stomodeum
* chin, lower lip, and cheek regions
53
Which pharyngeal arch will develop into muscles of facial expression?
Second pharyngeal arch
54
When do primordial auricles begin developing in utero?
End of week 5: 3 bilateral pairs of auricular hillocks from near first pharyngeal groove
55
How do the ears shift at the end of week 5 in utero?
Ears migrate up from neck region as mandible develops
56
When do maxillary and lateral nasal prominences begin fusion at nasolacrimal duct in utero?
End of week 6
57
When does oronasal membrane rupture in utero?
End of week 6
58
When will conchae and olfactory epithelium develop in utero?
By week 12
59
How do air sinuses of the face develop?
* Maxillary sinuses: fetal development
* Other air sinuses: after birth
60
What is the cause of a chin dimple?
Incomplete fusion of left and right mandibular prominences
61
The development of palate begins...
week 6 in utero
62
What is the primary palate in development?
Premaxillary part of maxillae
63
What is the secondary palate in development?
Lateral palatine processes (palatine shelf)
64
How common is a cleft lip?
Who is more likely to have a cleft lip?
1 in 1000 births
males > females (60-80% males)
65
How common is a cleft palate?
Who is more likely to have a cleft palate?
1 in 2500 births
females > males
66
Optic vesicles project from...
forebrain
67
Optic vesicles invaginate to form...
optic cups
68
Optic cups develop into...
retina and ciliary body
69
Surface ectoderm of the eye forms...
lens placode
70
Lens placode develops into...
lens
71
Surface ectoderm of the ear thickens into...
otic placode
72
Otic placode invaginates to form...
otic pit
73
The edges of the otic pit fuse to form...
otic vesicle which forms inner ear
74
The middle ear (ossicles and auditory tube) develop from which parts of the pharyngeal apparatus?
First and second arches
75
The external ear develops from which parts of the pharyngeal apparatus?
First and second arches, and first pharyngeal groove
76
What is the first endocrine gland to develop?
Thyroid gland
77
Thyroid primordium can be found...
on back of tongue/pharynx
78
The thyroid primordium descends to neck through...
thyroglossal duct
79
When will the thyroid primordium descend to the neck in utero?
24 days
80
When will the thyroid gland assume adult shape and reach the final site in anterior midline of neck?
By week 7 in utero
81
When will the thyroglossal duct degenerate in utero?
By week 7
82
In an adult, proximal opening of thyroglossal duct persists as...
foramen cecum on tongue
83
How does a persistent thyroglossal duct appear in an adult?
Round firm mass (swelling) in median plane of neck inferior to hyoid bone
84
A patient is born without a thymus gland and inferior parathyroid glands
Which portion of the pharyngeal apparatus is involved in this defect?
Third pharyngeal pouch
85
Treacher-Collins syndrome is characterized by malformed or absent ears, zygomatic and mandibular hypoplasia, and downward slanted eyes
This condition involves which pharyngeal arch?
First pharyngeal arch
86
A patient notices asymmetry in her neck when she tenses the skin of her inferior face and neck; she is lacking a platysma on one side of her neck
This asymmetry involves which pharyngeal arch?
Fourth and sixth pharyngeal arches
