Embryology Flashcards
Pharyngeal arches form from _________
the migration and proliferation of neural crest cells
Pharyngeal arches are separated by ________ and _________
pharyngeal grooves and clefts
Outside covering of pharyngeal arches
ectoderm
Inside lining of pharyngeal arches (one exception)
endoderm
-Arch 1 has oral ectoderm on inside
what makes up the core of each arch?
mesenchyme
Pharyngeal pouch
separates pharyngeal arches from the endoderm lined insides
pharyngeal membrane
where ectoderm and endoderm come together at clefts/grooves
1st pharyngeal arch, neural crest derivative
- Mandibular prominence (Meckel’s cartilage, mandible, malleus, incus, anterior ligament of malleus)
- Maxillary prominence?
Mandibular prominence (5), neural crest derivative
- Meckel’s cartilage
- mandible
- malleus
- incus
- anterior ligament of malleus
2nd pharyngeal arch (4), neural crest derivative
- lesser cornu of hyoid (superior hyoid)
- stylohyoid
- styloid process
- stapes
3rd pharyngeal arch (2), neural crest derivative
body and greater cornu of hyoid (inferior hyoid)
4th pharyngeal arch (1), neural crest derivative
laryngeal carliages
1st pharyngeal arch = ?
mandibular
2nd pharyngeal arch = ?
hyoid
1st pharyngeal arch (2) (mesoderm derivatives)
- All muscles of mastication
- anterior belly of digastric
2nd pharyngeal arch (2) (mesoderm derivatives)
- Muscles of facial expression
- posterior belly of digastric
3rd pharyngeal arch (1) (mesoderm derivatives)
stylopharngeus
4th/6th mesodermal arch (mesoderm derivatives) (3)
- pharyngeal constrictors
- soft palate muscles
- laryngeal muscles
1st pharyngeal arch (innervation)
trigeminal nerve (V)
2nd pharyngeal arch (innervation)
Facial nerve (VII)
3rd pharyngeal arch (innervation)
Glossopharyngeal (IX)
4th/6th pharyngeal arch (innervation)
vagus (X)
1st pharyngeal pouch (endoderm) (2)
middle ear cavity
auditory tube
2nd pharyngeal pouch (endoderm) (1)
palatine tonsil
3rd pharyngeal pouch (endoderm) (2)
Inferior parathyroid glands
Thymus
4th pharyngeal pouch (endoderm) (2)
superior parathyroid glands
ultimobranchial bodies
Pharyngeal groove 1
external acoustic meatus
Pharyngeal groove 2-4
cervical sinus –> cervical vesicle
Thyroid develops from…
endoderm between pharyngeal arch 1 and 2
Median lingual swelling derived from…
1st arch
Lateral lingual swellings (anterior 2/3 of tongue) derived from…
1st arch
Copula derived from…
2nd arch
Hypopharnygeal eminence (posterior 1/3 of tongue) derived from…
3rd and 4th arches
The tongue is well formed by week ________
10
Skeletal muscles of the tongue derived from ___________
occipital somites
________ nerve pulled with occipital somites to innervate (motor) skeletal muscles of the tongue
hypoglossal
Anterior 2/3 of the tongue:
- Somatosensory?
- Special Sensory?
somatosensory = V2
special sensory = VII
Posterior 1/3 of tongue
- Somatosensory?
- Special sensory?
somatosensory = IX and X
special sensory = IX
Motor innervation of the tongue
XII
Papillae of tongue form by week ________
8
4 types of tastebuds
1) filiform
2) fungiform*
3) folliate*
4) circumvallate*
- = contain tastebuds
Face formation begins in week ______
4
Median nasal prominences fuse between week ____ - ____
6-10
Median nasal prominence (derived from maxillary prominence) gives rise to
- Bridge of the nose
- Intermaxillary segment (philtrum, upper jaw with 4 incisors, primary palate)
philtrum derived from…
intermaxillary segment (MxP)
upper jaw and 4 incisors derived from…
intermaxillary segment (MxP)
Primary palate derived from…
intermaxillary segment (MxP)
Fusion of maxillary prominence with the intermaxillary segment results in…
- smooth upper lip
- fusion of primary and secondary palate
Alae derived from
Lateral nasal prominence (MxP)
Failure of the lateral nasal prominence to fuse with the maxillary prominence results in…
facial cleft
Secondary palate derived from…
fusion of palatine shelves that grow from the maxillary prominence
Secondary palate gives rise to…
majority of hard palate, all of soft palate
Primary palate gives rise to…
anterior hard palate
Palatine shelves fuse around week ______ when ________
9
the mandible “drops” tongue
Palatine shelves fuse with eachother and with _______
primary palate anteriorly
Secondary palate formation complete at week ______
12
Cleft lip results when…
intermaxillary segment and maxillary prominence fail to fuse (can be unilateral or bilateral)
Cleft palate results when…
palatal shelves fail to fuse
Oblique cleft results when…
lateral nasal prominence fails to fuse with the maxillary prominence