Exam 1 - Orofacial Development Flashcards
(126 cards)
1
Q
During which stage of human development do the germ layers mature and differentiate into specific tissues?
A
embryonic period
2
Q
A ____ is formed by the mitotic cleavage of the zygote.
A
blastomere
3
Q
A ____ is a group of more than 32 blastomeres.
A
morula
4
Q
Which structure of the proliferation period contains a cavity lined with cells?
A
blastocyst
5
Q
A ____ is the 64-cell stage morula once it develops an internal blastocystic cavity.
A
blastocyst
6
Q
A ____ is the name for a blastocyst once it develops an inner cell mass around day 6-7.
A
embryoblast
7
Q
When does implantation of the embryoblast into the uterine wall occur?
A
day 4-10
8
Q
The outer cell mass becomes the ____; the inner cell mass becomes the _____.
A
cytotrophoblast and syncytiotrophoblast layers; bilaminar embryonic disc
9
Q
Does the cytotrophoblast or syncytiotrophoblast “finger” into the uterine wall?
A
syncytiotrophoblast
10
Q
Which layers are precursors to the placenta?
A
the outer cell mass that becomes the cytotrophoblast and syncytiotrophoblast layers
11
Q
What are the two layers of the bilaminar embryonic disc?
A
epiblast
hypoblast
12
Q
The ____ of the bilaminar embryonic disc forms the ectoderm and then eventually the mesoderm.
A
epiblast
13
Q
The ____ of the bilaminar embryonic disc forms the endoderm layer.
A
hypoblast
14
Q
What membrane is formed by the enlargement of the amniotic cavity and migration of cells from the hypoblast?
A
Heuser’s membrane
15
Q
What structure forms the internal lining of the blastocyst cavity to form the embryonic yolk sac?
A
Heuser’s membrane
16
Q
What are the 3 cell layers and 3 embryonic cavities formed and present after complete implantation into the endothelial lining?
A
epiblast
embryonic mesoderm
hypoblast
amniotic cavity
yolk sac
chorionic cavity
17
Q
Where is the embryonic mesoderm located?
A
between the amniotic cavity and yolk sac
18
Q
Which embryonic cavity surrounds the entire structure/embryo in the uterine wall?
A
chorionic cavity
19
Q
During the 3rd week of development, the bilaminar disc is characterized by the formation of the _____.
A
primitive streak
20
Q
What structure starts to form from the cells of the epiblast layer migrating and invaginating to form the mesodermal layer?
A
primitive streak
21
Q
The primitive node turns into the _____, which turns into the _____.
A
notochordal process; notochord
22
Q
The notochord is formed from _____ cells derived from the primitive node.
A
ectodermal
23
Q
What blocks further progression of pre-notochordal cells? What is the “road block?”
A
prechordal plate
24
Q
Prenotochordal cells invaginate and migrate towards the ____ until they reach the prechordal plate.
A
cephalad
25
Prenotochordal cells detach and line up within the _____ layer to form the appropriate midline and form the notochord.
mesoderm
26
What functions as a primitive axial skeleton for the embryo?
notochord
27
What establishes the symmetry and polarity of embryonic development?
notochord formation
28
Does the notochord make somites?
NO
29
What is the role of the notochord in somite formation?
it INDUCES the formation of somites by other cells
30
____ are the precursors of the vertebral column, ribs, associated back muscles, and overlying dermis.
Somites
31
What structure is the precursor to nerves of the spinal column?
neural tube
32
The notochord stimulates the ____ layer to invaginate and form a round tube called the neural tube.
ectodermal
33
What cells form the peaks of the groove that eventually fuses together to create the neural tube?
neural crest cells
34
Where does fusion of the neural tube begin? Where does it fan out to?
starts in the middle; continues outward towards the head and the tail
35
What embryonic precursor cells eventually make the dorsal root ganglion?
neural crest cells
36
During the 3rd week of development, the bilaminar disc forms what 3 layers?
ectoderm
mesoderm
endoderm
37
The ectoderm was formerly the ____ layer.
epiblast
38
This layer forms the epidermis, hair, skin and nails.
ectoderm
39
This layer forms the epithelium of the oral and nasal cavities and paranasal sinuses.
ectoderm
40
This layer forms the salivary and endocrine glands, sweat glands, and the nervous system.
ectoderm
41
Which embryonic layer forms tooth enamel?
ectoderm
42
What is paraxial mesoderm?
somites "around the axis"
43
The ____ mesoderm forms the urogenital system.
intermediate
44
What are the two subtypes of lateral plate mesoderm?
parietal mesoderm
| visceral mesoderm
45
This layer forms the serous membranes that cover the peritoneal, pleural, and pericardial cavities.
parietal mesoderm
46
This layer forms the thin serous membranes that cover individual organs.
visceral mesoderm
47
The endoderm was formerly the ____ layer.
hypoblast
48
This layer forms the GI tract epithelium and its associated glands.
endoderm
49
Which developmental defect occurs when the bottom of the neural tube does not fuse, usually from a folic acid deficiency?
spina bifida
50
Which development defect occurs when extrusion of the dura and arachnoid mater occurs?
meningocele
51
Which development defect occurs when there is extrusion of the meninges and neural tissue?
meningomyelocele
52
Which developmental defect occurs when the ventricular cistern (deep brain) is extruded, along with neural tissue?
meningoencephalocele
53
This developmental defect is fatal and is characterized by a lack of cranial development and brain.
anencephaly
54
_____ differentiate into dorsal root ganglion and sensory ganglion for CN V, VII, IX, and X.
Neural crest cells
55
What structures can neural crest cells make?
```
dermis
connective tissue of the eye
CN ganglion
odontoblasts
pharyngeal arches
melanocytes
adrenal medulla
meninges
facial bones
cartilage
teeth/periodontal structures
```
56
The neural crest cells make sensory ganglion for which cranial nerves?
V, VII, IX, X
57
What two things can neural crest cells NOT make?
enamel
| gingiva
58
Enamel and gingiva are made via which embryonic origin layer?
ectoderm
59
What structures do all branchial/pharyngeal arches contain?
1 nerve
1 artery
1 piece of cartilage
60
The ___ branchial groove/cleft is formed by the mandibular and maxillary arches coming together.
1st
61
What branchial arch forms the external auditory canal?
1st branchial groove/cleft
62
What branchial arch forms the Eustachain tubes?
1st branchial pouch
63
Where does the ear drum form within the branchial/pharyngeal arches?
between the 1st groove and the 1st pouch
64
What branchial arch forms the palatine tonsils?
2nd branchial pouch
65
What branchial arch forms the inferior parathyroids and the thymus?
3rd branchial pouch
66
What branchial arch forms the superior parathyroids and the ultimobranchial body?
4th branchial pouch
67
At which day mark does cervical flexure of the brain occur, as well as the formation of the maxillary and mandibular prominences and limb formation?
32 days
68
At which day mark does pigmentation of the eye, formation of the auricular hillocks, and the external ear occur?
41 days
69
What are the lumps called that form the external ear?
auricular hillocks
70
At which point is the baby pretty much developed?
at the end of the embryonic period
71
When do tissues and organs start to function in developement?
at the start of the fetal development period
72
Does the head increase or decrease relative to the size of the body?
DECREASES (50% to 30%)
73
What are the 4 processes that the face develops from?
mandibular process
maxillary process
lateral nasal process
median nasal process
74
What does the mandibular process form?
chin
75
What does the maxillary process form?
cheeks
76
What do the lateral nasal processes form?
nose
77
What do the median nasal processes form?
philtrum of lip
78
What structure is formed from the coming together of the 4 processes?
stomadeum (primitive mouth)
79
At what week does the buccopharyngeal membrane disintegrate to allow mouth to gut communication?
4th week
80
At what week does the median nasal process fuse with the maxillary process?
5th/6th week
81
The defective fusion of which two processes results in a cleft lip?
median nasal process
| maxillary process
82
When would a cleft lip be detected in utero?
around the 5th to 6th week (35th day)
83
The defective fusion of what structure results in a cleft palate?
palatine shelves
84
When would a cleft palate be detected in utero?
8th to 12th week
85
What is the triangular area of the median nasal processes called?
primary palate
86
The primary palate attaches to the ____ and seals it in a posterior direction.
maxillary processes
87
How many ossification centers are present on the palate?
4
88
What percent of facial clefts are combined cleft lip and cleft palate?
45%
89
What is the most common cyst of the fusion lines?
nasopalatine duct cyst
90
Which type of cyst develops at the line of fusion between the palatine shelves and the primary palate?
nasopalatine duct cyst
91
You notice on your patient's x-ray that she has a space between her central incisors and that they have deflected roots. What anomaly do you predict?
nasopalatine duct cyst
92
Where do lateral cervical cysts/branchial fistulas occur?
follows along the sternocleidomastoid muscle
93
When do lateral cervical cysts develop?
develop when the cervical sinus remains past the 7th week
94
What structure remains that causes the formation of a lateral cervical cyst?
cervical sinus remnant
95
Which arch covers the clefts on the outside of the head that are normally filled in by week 7?
2nd arch
96
Which two pharyngeal arches contribute to the formation of the tongue?
1st and 3rd
97
The anterior 2/3 of the tongue is made from cells of the ___ pharyngeal arch.
1st
98
What fetal intermediate structure from the 1st pharyngeal arch makes up the anterior 2/3 of the tongue in an adult?
lateral lingual swellings
99
What is the anterior 2/3 of the tongue innervated by?
mandibular branch of the trigeminal nerve (CN V)
100
The posterior 1/3 of the tongue is made from cells of the ___ pharyngeal arch.
3rd
101
What fetal intermediate structure from the 3rd pharyngeal arch makes up the posterior 1/3 of the tongue in an adult?
hypobranchial eminence
102
The posterior 1/3 of the tongue in innervated by which nerves?
glossopharyngeal (CN IX)
| vagus (CN X)
103
What is the origin of the thyroid gland?
foramen cecum (thyroid tissue invaginates downwards through the hole and migrates down)
104
Where would you find the foramen cecum?
at the junction of the anterior and posterior portions of the tongue
105
What is median rhomboid glossitis associated with?
candida albicans (yeast)
106
What develops if the thyroglossal duct fails to involute properly at the foramen cecum?
thyroglossal duct cyst
107
Which cyst is found in the midline of the neck due to a failure of the descent of the thyroid gland?
thyroglossal duct cyst
108
A lateral cervical cyst always occurs ____; a thyroglossal duct cyst always occurs ____.
along the sternocleidomastoid; along the midline of the neck
109
An ____ occurs if the thyroid gland does not involute the tongue at all. What forms where the foramen cecum should be?
ectopic lingual thyroid; nodule of lymph tissue
110
What structure is the precursor to the anterior tongue?
lateral lingual swellings
111
What structure is the precursor to the posterior tongue?
hypobranchial eminence
112
Which arch has lateral lingual swelling and foramen cecum precursors, forms into the anterior 2/3 of the tongue, has innervation from the trigeminal nerve, and provides sensory to the anterior 2/3 of the tongue?
1st branchial arch
113
Which arch contains the tuberculum impar?
2nd arch
114
Which branch is overgrown by the hypobranchial eminence?
2nd arch
115
Which arch is innervated by the facial nerve?
2nd arch
116
Which arch provides taste sense to the anterior 2/3 of the tongue via the chorda tympani branch?
2nd arch
117
Which arch contains the hypobranchial precursor which eventually turns into the posterior 1/3 of the tongue?
3rd arch
118
Which arch and nerve provides sensory to the posterior 1/3 of the tongue?
3rd arch; glossopharyngeal nerve
119
Which arch provides sensory to the extreme posterior tongue via the superior laryngeal; branch of the vagus nerve?
4th arch
120
Which arch provides motor innervation to all tongue muscles via the hypoglossal nerve?
6th arch
121
The 1st arch is also called _____.
Meckel's cartilage
122
The 2nd arch is also called _____.
Reichart's cartilage
123
Which bony structures does Meckel's cartilage eventually form?
maleus
incus
mandible
124
Which bony structures does Reichart's cartilage eventually form?
stapes***
styloid process
stylohyoid ligament
lesser horn of hyoid
125
Which bony structure does the 3rd arch eventually form?
greater horn of hyoid
126
Which bony structure does the 4th arch eventually form?
thyroid cartilage
