Week 1 Oral Facial Development and Abnormalities Flashcards

1
Q

what are the 3 stages of human development and how long are each

A

proliferation period (0-3 weeks)
embryonic period (3-8 weeks)
fetal development period (9 weeks to term)

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2
Q

what happens in the proliferation period

A

-fertilization of ovum yields zygote
-mitotic cleavage of zygote forms blastomeres
-more than 32 blastomeres becomes a morula
-keeps dividing then is referred to as a blastocyst
-then travels down uterus and attaches to wall and is called an embryoblast
-inner cell mass of the embryoblast becomes bilaminar embryonic disc
-outer cell mass becomes the cytotrophoblast and syntrophoblast

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3
Q

what is a cyst

A

any mass that is lined with a cells and is hollow inside

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4
Q

when does implantation of the embryoblast in the uterine wall begin and complet

A

begins at day 4 and is complete at day 10

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5
Q

what layers are precursors to the placenta

A

cytotrophoblast and syntrophoblast

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6
Q

what are the layers of the bilaminar embryonic disc

A

epiblast and hypoblast

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7
Q

what makes up the epiblast layer

A

ectoderm and mesoderm

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8
Q

what makes up the hypoblast layer

A

endoderm

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9
Q

what are the structures associated with the bilaminar embryonic disc

A

epiblast layer
hypoblast layer
amniotic cavity
blastocyst cavity
syntrophoblasts
cytotrophoblasts

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10
Q

what forms Heuser’s membrane

A

enlargement of the amniotic cavity and migration of cells out of the hypoblast

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11
Q

what does Heusers membrane form

A

the internal lining of the blastocyst cavity now called the yolk sac

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12
Q

what are the cell layers in the proliferation period

A

epiblast, embryonic mesoderm, hypoblast

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13
Q

what are the embryonic cavities in the proliferation period

A

amniotic
yolk sac
chorionic

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14
Q

during the 3rd week of development, the bilaminar embryonic disc is characterized by the formation of what

A

-primitive streak
-notochord
-neural tube

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15
Q

what are the three distinct emrbyonic germ layers during the 3rd week of development

A

ectoderm, mesoderm, and endoderm

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16
Q

what does the ectoderm develop from

A

the epiblast layer

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17
Q

what does the endoderm develop from

A

hypoblast layer

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18
Q

what are the 3 features of the primitive streak

A

pit, node, and groove

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19
Q

what does the primitive node turn into

A

notochordal process -> notochord

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20
Q

how do pre-notochordal cells form the notochord

A

the cells invaginate within the primitive node and migrate towards the cephalad until they reach the prechordal plate. they then detach themselves from the ectodermal layer to line within the mesoderm forming the notochord

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21
Q

what does the notochord do

A
  • functions as a primitive skeletal support of the embryo around which the axial skeleton later forms
  • induces formation of somites, the precursor of the vertebral column, ribs, associated back muscles and the overlying dermis
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22
Q

what layer does the notochord form from

A

the ectoderm

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23
Q

what are the different parts of mesoderm

A

-paraxial mesoderm
-intermediate mesoderm
-lateral plate mesoderm

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24
Q

what are the 2 parts of the lateral plate mesoderm

A

visceral and parietal

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25
Q

what does the paraxial mesoderm form

A

somites

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26
Q

what does the intermediate mesoderm form

A

urogenital system

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27
Q

what does each part of the lateral plate mesoderm form

A

-parietal- mesothelial membranes that cover the peritoneal, pleural and pericardial cavities
- visceral- forms the thin serous membranes that cover individual organs

28
Q

what are the derivatives of the ectoderm

A

-epidermic, hair and nails
-epithelium of the oral and nasal cavities and paranasal sinues
-salivary and endocrine glands
-nervous system
-tooth enamel

29
Q

what are the derivatives of the endoderm

A

GI tract epithelium and associated glands

30
Q

what happens when the neural tube does not form correctly

A

developmental defects in the brain and spinal cord

31
Q

what are other names for neural crest cells

A

ectomesenchyme and neuroectoderm

32
Q

what arches are seen during the embryonic period

A

branchial/pharyngeal arches

33
Q

what does the 1st brachial groove form

A

external auditory canal

34
Q

what does the 1st brachial pouch form

A

eustachian tube

35
Q

what does the 2nd branchial pouch form

A

palatine tonsils

36
Q

what does the 3rd brachial pouch form

A

inferior parathryoids/thymus

37
Q

what does the 4th brachial pouch form

A

superior parathyroids/ultimobranchial body

38
Q

what happens to the proportion of the head to the rest of the body from 3-9 months

A

the head stays the same size and the body growa

39
Q

what are the processes in the development in the face

A
  • mandibular process
  • maxillary process
    -lateral nasal process
  • median nasal process
40
Q

what defective fusion results in cleft lip

A

medial nasal process with the maxillary process

41
Q

when does the fusion of the medial nasal process and the maxillary process occur

A

5-6 weeks of gestation

42
Q

what defective fusion results in cleft palate

A

the palatine shelves

43
Q

when does fusion of the palatine shelves occur

A

8th-12th week of gestation

44
Q

what is the incidence rate of combine cleft lip and palate, isolated cleft palate and isolated cleft lip

A

combined- 45%
isolated cleft palate- 30%
isolated cleft lip - 25%

45
Q

what is the incidence of cleft palate alone

A

1 in 2,500

46
Q

what substances are known to be involved in congenital malformation

A

-radiation
-chemicals
-drugs such as ethanol, tetracycline, dilantin, lithium, warfarin, methotrexate, androgens, progesterone, retinoic acid

47
Q

where does the nasopalatine duct cysts occur

A

at line of fusion between palatine shelves and primary palate

48
Q

what is the relation between clefts and arches

A

clefts are on inside, arches are on outside

49
Q

why would a lateral cervical cyst/branchial fistula form

A

2nd bronchial archoesnt get resorbed and remains forming a cyst

50
Q

what arches does the tongue develop from

A

1st-4th branchial arches

51
Q

what is the intermediate structure and the adult structure of the 1st branchial arch

A

intermediate- median tongue and foramen cecum and lateral lingual swellings
adult- overgrown by lateral lingual swellings, origin of the thyroid ectoderm, anterior 2/3 of the tongue

52
Q

what is the intermediate and adult structure of the second branchial arch

A

intermediate- copula/tuberculum impar
adult- overgorwn by the hypobranchial eminence

53
Q

what is the intermediate and adult structure of the third branchial arch

A

intermediate- hypobranchial eminence
adult- posterior 1/3 of the tongue

54
Q

what is the intermediate and adult structure of the fourth branchial arch

A

intermediate- minor contributions to the hypobranchial eminence
adult- none

55
Q

what is the innervation and tongue structure of the first arch

A

innervation- trigeminal
tongue structure- sensory to the anterior 2/3

56
Q

what is the innervation and tongue structure of the second arch

A

inneravtion- facial
tongue structure- special sensory to anterior 2/3 via the chorda tympani branch

57
Q

what is the innervation and tongue structure of the third arch

A

innervation- glossopharyngeal
tongue structure- sensory to the posterior 1/3

58
Q

what is the innervation and tongue structure of the fourth arch

A

innervation- vegas
tongue structure- sensory tot he extreme posterior 1/3 via the superior laryngeal branch

59
Q

what is the innervation and tongue structure of the sixth arch

A

innervation: hypoglossal
tongue structure: motor to all tongue muscles

60
Q

what is a thyroglossal duct cyst and where is it located

A

failure of thyroglossal duct to involute located in midline of the neck

61
Q

what cartilage does each brachial arch form

A

1- Meckel’s cartilage - forms mandibe, maleus, incus
2- Reichart’s cartilage- forms stapes, styloid process, stylohyoid ligament, lesser horn of hyoid
3- greater horn of hyoid
4- thyroid cartilage

62
Q

What causes median rhomboid glossitis

A

Result of a final infection

63
Q

What does the neural tube become? Notochord?

A

Neural tube- brain and spinal cord
Notochord- vertebral column

64
Q

What are derivatives of cranial neural crest cells

A

Odontoblasts, pharyngeal arch cartilages, connective tissue surrounding eye, dermis and hypodermics of face and neck, some cranial nerve ganglia

65
Q

What are derivatives of spinal neural crest cells

A

Preaortic ganglia, adrenal medulla, dorsal root ganglia

66
Q

What are lateral lingual swellings precursors for

A

Anterior tongue

67
Q

What are hypobranchial eminence precursors for

A

Posterior tongue