development of face Flashcards

1
Q

developing fetus composed of three layers of tissue

A
  • ectoderm
  • mesoderm
  • endoderm
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2
Q

third week

A
  • 3mm
  • early forebrain - prosencephalon
  • below is furrow - oral groove- stomadeum
  • early mouth
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3
Q

fourth week

A
  • 4.5 mm
  • branchial apparatus emerges
  • developed by 28 days
  • branchial arches, pharyngeal pouches, branchial grooves
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4
Q

branchial arches

A

-5 in human numbered 1-6
only 1&2 named
-much of face derived from these

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5
Q

arch 1

A
mandibular
skeletal:
-mandible
-anterior tongue
-lower lip
-malleus
-incus
muscles:
-muscles of mastication
-ABD
-tensor tympani
-tensor palatini
innervation:
-CN V - V3
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6
Q

arch 2

A
hyoid
skeletal:
-stapes
-styloid process
-stylohyoid ligament
-body of hyoid
-lesser horns of hyoid
muscles:
-stapedius
-stylohyoid
-muscles of facial expression
-PBD
innervation:
-CN VII
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7
Q

arch 3

A
skeletal:
-lower part of hyoid
-posterior tongue
muscles:
-stylopharyngeus
innervation:
-CN IX - glossopharyngeal
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8
Q

arch 4-6

A
skeletal:
-laryngeal cartilages
muscles:
-cricothyroid
-pharyngeal constrictors
-intrinsic laryngeal muscles
innervation:
-CN X
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9
Q

brachial cleft 1

A
  • external auditory meatus

- ectodermal aspect of TM

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10
Q

brachial cleft 2-4

A

-cervical sinus

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11
Q

fourth week processes

A
  • area cephalic to stomadeum forms the frontonasal process - frontonasal prominance
  • thickenings appear on sides of process
  • nasal - olfactory placodes
  • pits = early nasal openings
  • pits divide face into lateral and medial nasal processes
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12
Q

fifth week

A

9 mm

  • branchial arches reach most prominent appearance
  • face divided in 4 regions
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13
Q

frontonasal process

A
  • medial/lateral processes

- lateral - globular process

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14
Q

mandibular arch

A
  • 1st branchial arch fuse in midline

- forms caudal border of stomadeum

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15
Q

maxillary process

A

-2 small processes from laterally between 2 mandibular arch and lateral nasal process

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16
Q

hyoid arch

A
  • partially interrupted by bulge of rapidly growing heart

- appears as two sac-like pouches on either side of neck region

17
Q

early face

A
  • 32 days

- 5th week

18
Q

sixth week

nasal processes

A
  • medial nasal processes forms upper border of mouth
  • maxillary processes formed into wedge like processes below early eye
  • not fused
  • separated by small grooves that must disappear
  • medial and lateral nasal processes fuse
  • thin shelf of tissue separates a portion of oral and nasal cavities *primary plate
  • forms nasal laminae - septum
  • philtrum on face is point of fusion of lateral and medial nasal processes
19
Q

sixth week

A

9 mm

  • anterior directed growth of face begins
  • eyes developing at sides of face drawn medially
  • small buds form at first branchial groove
  • buds = auricle
20
Q

seventh week

A
  • pronounced change in face
  • nasal area becomes prominent but decreases in width
  • eyes move into anterior surface
  • critical period for palate formation
21
Q

primary palate begins to develop

A
  • tissue begins to develop in 4th week
  • maxillary process fuses with medial nasal process
  • fusion between lateral and medial nasal processes
  • bar of tissue separating nasal duct from oral cavity IS primary palate
22
Q

primary palate formation

A
  • forms upper lip, anterior alveolar process and premaxillary palate
  • completed by 8 weeks
23
Q

week 8

A
  • head begins to expand vertically
  • increases height of oral cavity
  • allows growth of nasal septum
  • no separation of oral and nasal cavity
24
Q

development of secondary palate

A
  • initially developing tongue fills oral and nasal cavities
  • maxillary processes are folds of tissue on either side of tongue
  • development of palate and growth of head allows tongue to drop into oral cavity
  • maxillary processes grow rapidly and extend horizontally
  • palatine processes fuse with each other and nasal septum
  • fusion takes places in anterior to posterior direction
  • palatine processes form posterior hard palate and soft palate
  • globular process from early nasal processes grows inward to form tectal plate
  • tectal plate is early premaxillary process
25
risk factor period
-week 4-8 | cleft-lip palate risk
26
general development
- week 3-8 face | - week 6-9 palate
27
development of tongue | week 3
- lateral lingula swellings on internal mandibular arch - in between swellings is elevation called tuberculum impar * rapidly proliferating mesoderm - lateral lingula & tuberculum merge together to form anterior tongue - also coupla in midline behind TI - copula bridges 2 & 3 branchial arches - posterior portion of copula forms epiglottis
28
development of tongue | week 5
-tuberculum and copula prominently developed
29
tongue development | week 6
-primitive tongue shape evident
30
tongue development | week 7
- tuberculum impar grows backwards in a V shape to form sulcus terminalis - tissues on either side of copula form quickly to produce a tongue like structure - copula forms posterior tongue while tuberculum impar forms anterior tongue * rapid exponential growth of tongue fills in oral cavity
31
development of tongue | -composition
- initially just composed of mucous membrane - tongue muscles eventually migrate in * tongue membrane derived from branchial arches but muscles are NOT
32
tongue muscles formed from
occipital somites
33
somites
- masses of mesoderm distributed along two sides of neural tube - eventually become dermis, skeletal muscle, and vertebrae
34
what do somites form
- rib and vertebrae cartilage - muscles (skeletal muscles - tongue and ocular) - rib cage - limbs - abdominal wall - back and tongue - dorsal skin dermis