Week 1 Oral Facial Development and Abnormalities Flashcards by Olivia Bellantoni

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

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

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what happens in the proliferation period

-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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what is a cyst

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

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

begins at day 4 and is complete at day 10

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what layers are precursors to the placenta

cytotrophoblast and syntrophoblast

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what are the layers of the bilaminar embryonic disc

epiblast and hypoblast

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what makes up the epiblast layer

ectoderm and mesoderm

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what makes up the hypoblast layer

endoderm

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what are the structures associated with the bilaminar embryonic disc

epiblast layer
hypoblast layer
amniotic cavity
blastocyst cavity
syntrophoblasts
cytotrophoblasts

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what forms Heuser’s membrane

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

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what does Heusers membrane form

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

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what are the cell layers in the proliferation period

epiblast, embryonic mesoderm, hypoblast

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what are the embryonic cavities in the proliferation period

amniotic
yolk sac
chorionic

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

-primitive streak
-notochord
-neural tube

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

ectoderm, mesoderm, and endoderm

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what does the ectoderm develop from

the epiblast layer

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what does the endoderm develop from

hypoblast layer

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what are the 3 features of the primitive streak

pit, node, and groove

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what does the primitive node turn into

notochordal process -> notochord

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how do pre-notochordal cells form the notochord

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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what does the notochord do

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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what layer does the notochord form from

the ectoderm

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what are the different parts of mesoderm

-paraxial mesoderm
-intermediate mesoderm
-lateral plate mesoderm

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what are the 2 parts of the lateral plate mesoderm

visceral and parietal

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what does the paraxial mesoderm form

somites

what does the intermediate mesoderm form

urogenital system

what does each part of the lateral plate mesoderm form

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

what are the derivatives of the ectoderm

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

what are the derivatives of the endoderm

GI tract epithelium and associated glands

what happens when the neural tube does not form correctly

developmental defects in the brain and spinal cord

what are other names for neural crest cells

ectomesenchyme and neuroectoderm

what arches are seen during the embryonic period

branchial/pharyngeal arches

what does the 1st brachial groove form

external auditory canal

what does the 1st brachial pouch form

eustachian tube

what does the 2nd branchial pouch form

palatine tonsils

what does the 3rd brachial pouch form

inferior parathryoids/thymus

what does the 4th brachial pouch form

superior parathyroids/ultimobranchial body

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

the head stays the same size and the body growa

what are the processes in the development in the face

- mandibular process - maxillary process -lateral nasal process - median nasal process

what defective fusion results in cleft lip

medial nasal process with the maxillary process

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

5-6 weeks of gestation

what defective fusion results in cleft palate

the palatine shelves

when does fusion of the palatine shelves occur

8th-12th week of gestation

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

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

what is the incidence of cleft palate alone

1 in 2,500

what substances are known to be involved in congenital malformation

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

where does the nasopalatine duct cysts occur

at line of fusion between palatine shelves and primary palate

what is the relation between clefts and arches

clefts are on inside, arches are on outside

why would a lateral cervical cyst/branchial fistula form

2nd bronchial archoesnt get resorbed and remains forming a cyst

what arches does the tongue develop from

1st-4th branchial arches

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

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

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

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

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

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

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

intermediate- minor contributions to the hypobranchial eminence adult- none

what is the innervation and tongue structure of the first arch

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

what is the innervation and tongue structure of the second arch

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

what is the innervation and tongue structure of the third arch

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

what is the innervation and tongue structure of the fourth arch

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

what is the innervation and tongue structure of the sixth arch

innervation: hypoglossal tongue structure: motor to all tongue muscles

what is a thyroglossal duct cyst and where is it located

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

what cartilage does each brachial arch form

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

What causes median rhomboid glossitis

Result of a final infection

What does the neural tube become? Notochord?

Neural tube- brain and spinal cord Notochord- vertebral column

What are derivatives of cranial neural crest cells

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

What are derivatives of spinal neural crest cells

Preaortic ganglia, adrenal medulla, dorsal root ganglia

What are lateral lingual swellings precursors for

Anterior tongue

What are hypobranchial eminence precursors for

Posterior tongue

Week 1 Oral Facial Development and Abnormalities Flashcards

(67 cards)