Introductory Embryology, Oral-Facial Development And Associated Developmental Anomalies Flashcards

1
Q

Stages of human development: (3)

A

 Proliferation Period (0-3 weeks)
 Embryonic Period (3-8 weeks)
 Fetal Development Period
(9 weeks to term)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Fertilization of ovum yields —

A

zygote

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

mitotic cleavage of zygote forms —

A

blastomeres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

more than 32 blastomeres is called a —

A

morula

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The 64 cell stage morula develops an internal blastocystic cavity and thereafter is referred to as a

A

blastocyst

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The blastocyst also develops an inner cell mass at days 6-7

and thereafter is referred to as the

A

embryoblast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Implantation of the embryoblast in the uterine wall begins

at day - and is complete at day -

A

4, 10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

The inner cell mass of the embryoblast transitions into the

A

bilaminar embryonic disc

two layers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Outer cell mass becomes the (2)layers which are precursor to the placenta

A

cytotrophoblast & syntrophoblast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Epiblast Layer (2)

A

Ectoderm

Mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Hypoblast Layer (1)

A

Endoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Structures associated with the bilaminar embryonic disc (6)

A
  • Epiblast Layer
  • Hypoblast Layer
  • Amniotic Cavity
  • Blastocyst Cavity
  • Syntrophoblasts
  • Cytotrophobasts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Enlargement of the amniotic cavity and migration of cells out of the hypoblast to form

A

Heuser’s membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Heuser’s membrane will form the internal lining of the blastocyst cavity – now called the

A

yolk sac

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Cell layers (3)

A

 Epiblast
 Embryonic mesoderm
 Hypoblast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Embryonic cavities (3)

A

 Amniotic
 Yolk sac
 Chorionic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

During the 3rd week of development, the bilaminar

embryonic disc is characterized by formation of the: (3)

A

Primitive Streak
Notochord
Neural Tube

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

And the three distinct embryonic germ layers: (3)

A

Ectoderm (formerly the epiblast layer)
Mesoderm
Endoderm (formerly the hypoblast layer)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Primitive Streak (3)

A

 Pit
 Node
 Groove

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

steps in formation of the notochord

A

Primitive node → Notochordal Process → Notochord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

— cells invaginate within the — and migrate towards the cephalad until the reach the —. They detach themselves from the ectodermal layer to line within the mesoderm forming the —

A

Pre-notochordal
primitive node
prechordal plate
notochord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

The notochord functions as a

A

primitive skeletal support of the

embryo around which the axial skeleton later forms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

The notochord also induces formation of —, the precursors
of the vertebral column, ribs, associated back muscles and
overlying dermis.

A

somites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

formed from ectodermal cells derived from the —. The cells then migrate within the mesodermal layer to their appropriate midline position. The notochord functions as a primitive axial skeleton for the embryo, establishing symmetry and polarity of development and induction of the —

A

primitive node

somites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Lateral Plate Mesoderm (2)

A

 Parietal

 Visceral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q
Derivatives of Mesoderm:
• Paraxial mesoderm  → 
• Intermediate mesoderm →
• Lateral plate mesoderm:
Parietal mesoderm → 
Visceral mesoderm →
A

somites
urogenital system
mesothelial (serous) membranes that cover the peritoneal, pleural and pericardial cavities.
forms the thin serous membranes that cover individual organs,
e.g., stomach, pancreas, spleen, etc.

27
Q

Derivatives of Ectoderm: (5)

A
• Epidermis, hair and nails
• Epithelium of the oral and nasal cavities 
and paranasal sinuses 
• Salivary and endocrine glands
• Nervous system
• Tooth enamel
28
Q

Derivatives of Endoderm: (1)

A

• GI tract epithelium and associated glands

29
Q

Spina Bifida

A

folic acid deficiency

30
Q

Meningocele

A

extrusion of dura and arachnoid mater

31
Q

Meningomyelocele

A

extrusion of neural tissue plus all three meninges

32
Q

Meningoencephalocele

A

extrustion of a ventricular cistern plus neural tissue

33
Q

Anencephaly

A

fatal defect characterized by lack of development of

the cranium and brain

34
Q

The clinical consequences of a defect in neural tube closure
ranges from mild to fatal. — and — are examples of a mild defect. A slightly more severe defect is the —. Still more severe is the —. — is a fatal defect.

A
Spina bifida
meningocele
meningomyelocele
meningohydroencephalocele
Anencephaly
35
Q

Neural Crest Cells

a.k.a. (2)

A

Ectomesenchyme

Neuroectoderm

36
Q

1st branchial groove ⇒

A

external auditory canal

37
Q

1st branchial pouch ⇒

A

eustachian tube

38
Q

2nd branchial pouch ⇒

A

palatine tonsils

39
Q

3rd branchial pouch ⇒

A

inferior parathyroids/thymus

40
Q

4th branchial pouch ⇒

A

superior parathyroids/ultimobranchial body

41
Q

Development of the Face: (4) processes

A
  • Mandibular Process
  • Maxillary Process
  • Lateral Nasal Process
  • Median Nasal Process
42
Q

Defective fusion of the medial nasal process with the maxillary
process results in —. Fusion of these processes normally
occurs at — of gestation.

A

cleft lip

5-6 weeks

43
Q

Defective fusion of the palatine shelves results in —.
Fusion of the palatine shelves normally begins during the 8th
week of gestation and is completed by the —

A

cleft palate

12th week

44
Q

–% of all clefts are combined cleft lip/cleft palate.

A

45

45
Q

–% of cases are isolated cleft palate.

A

30

46
Q

—% of cases are isolated cleft lip.

A

25

47
Q

The incidence of cleft lip/cleft palate is:
• — in Chinese, Japanese and NativeAmerican populations
• — in Caucasian populations
• — in Afro-American populations

A

1 in 500 births
1 in 700 births
1 in 500 births

48
Q

The incidence of cleft palate alone is 1 in — births.

A

2,500

49
Q

If one child is born with cleft lip, there is a —% chance of a second child exhibiting the same defect.

A

40

50
Q

Known Teratogens Involved in Congenital Malformations
Drugs:
Chemicals:
Radiation:

A

Ethanol, Tetracycline, Dilantin, Lithium, Methotrexate, Warfarin, Thalidomide, Androgens, Progesterone, Retinoic Acid

Methylmercury, polychlorinated biphenyls

High levels of ionizing radiation

51
Q

Nasopalatine Duct Cyst develops at the line of fusion between

A

palatine shelves and primary plate

52
Q

cervical sinus remains past

A

7th week

53
Q

Embryonic Precursor: Branchial Arch #1
Intermediate Structure:
Adult Structure:

A

Median Tongue Bud
Foramen Cecum
Lateral Lingual Swellings

Overgrown by lateral lingual swellings
Origin of the thyroid ectoderm
Anterior 2/3 of the tongue

54
Q

Embryonic Precursor: Branchial Arch #2
Intermediate Structure:
Adult Structure:

A

Copula/Tuberculum Impar

Overgrown by the hypobranchial eminence

55
Q

Embryonic Precursor: Branchial Arch #3
Intermediate Structure:
Adult Structure:

A

Hypobranchial Eminence

Posterior 1/3 of the tongue

56
Q

Embryonic Precursor: Branchial Arch #4
Intermediate Structure:
Adult Structure:

A

Minor contributions to the hypobranchial eminence

None

57
Q

Branchial Arch: 1
Cranial Nerve:
Tongue Structure:

A

Trigeminal (C-V)

Sensory to the anterior 2/3

58
Q

Branchial Arch: 2
Cranial Nerve:
Tongue Structure:

A

Facial (C-VII)
Special sensory (taste) to anterior 2/3 via
the chorda tympani branch

59
Q

Branchial Arch: 3
Cranial Nerve:
Tongue Structure:

A

Glossopharyngeal (C-IX)

Sensory to the posterior 1/3

60
Q

Branchial Arch: 4
Cranial Nerve:
Tongue Structure:

A

Vegas (C-X)

Sensory to the extreme posterior 1/3 via the superior laryngeal branch

61
Q

Branchial Arch: 6
Cranial Nerve:
Tongue Structure:

A

Hypoglossal (C-XII)

Motor to all tongue muscles

62
Q

Median Rhomboid Glossitis: Was thought to represent a portion of the

A

tuberculum impar (branchial arch II) that persists, but now it is considered to be a result of a fungal infection.

63
Q

Branchial Arch Cartilage (4)

A
I:  (Meckel’s Cartilage)
Mandible, Maleus, Incus
II: (Reichart’s Cartilage)
Stapes, Styloid Process, 
Stylohyoid Ligament,
Lesser Horn of Hyoid
III: Greater Horn of Hyoid
IV:  Thyroid Cartilage