Embryology Flashcards
What are the three components of the pharyngeal apparatus
- Core pharyngeal arch (mesenchymal tissue)
- External pharyngeal cleft (ectoderm tissue)
- Internal pharyngeal pouch (endoderm tissue)
Clefs (external) and pouches (internal) line & separate arches
Core pharyngeal arch (__________ tissue)
Mesenchymal
External pharyngeal cleft (________ tissue)
Ectoderm
Internal pharyngeal pouch (_________ tissue)
Endoderm
Where does the pharyngeal arches develop from
Pharyngeal arches develop in the vertebrates
When do the pharyngeal arches develop
Week 4 & 6
How many pharyngeal arches are there
5 arches - 6 arches develop but number 5 ‘disappears’
So there is arch 1, 2, 3, 4 & 6
What are the four components of the pharyngeal arches
(Skeletal) musculature
Connective tissue & smooth muscles
Cranial nerves
Arteries (branch of aortic arch
Where do the skeletal muscles of the pharyngeal arch originate from
paraxial and lateral plate mesoderm
Where do the smooth muscles & connective tissue of the pharyngeal arch originate from
Neural crest cells
What innervates the 1st arch
What bones are formed from the 1st arch
What innervates the 2nd arch
What bones are formed from the 2nd arch
What muscles are formed from the 2nd arch
What innervates the 3rd arch
What bones are formed from the 3rd arch
What muscles are formed from the 3rd arch
What innervates the 4th arch
What bones are formed from the 4th arch
What muscles are formed from the 4th arch
What innervates the 6th arch
What bones are formed from the 6th arch
What muscles are formed from the 6th arch
What do the 2nd-4th clefts form
the cervical sinus (usually obliterates)
What is the clinical relevance of the cervical sinus
What does the 1st pouch form
What does the 2nd pouch form
What does the 3rd pouch form
What does the 4th pouch form
At what week does the tongue usually develop
4th week
The tongue forms from two ________ swellings & one _________ swelling. The lateral swelling occurs from the ___ arch and forms the ________________________. The midline swelling forms from the ___ & ___ arch and forms the ____________ & __________.
The tongue forms from two lateral swellings & one midline swelling. The lateral swellings occur from the 1st arch and form the anterior 2/3rd of the tongue. The midline swelling forms from the 3rd & 4th arches and forms the posterior 1/3rd of the tongue (the copula) and epiglottis.
What pharyngeal arch forms the anterior 2/3rds of the tongue & so what innervates it
1st arch - CN V3 (except for special sensory that it gets from chorda tympani)
What pharyngeal arch(s) forms the posterior 1/3rd of the tongue & so what innervates it
3rd & 4th - CN IX
Where do the tongue muscles originate from & so what innervates it
Occipital somites - Hypoglossal nerve (CN XII)
What is the copula
At what time in embryological development does the facial prominences appear
Week 4 & 5
What are the 5 facial prominences
•Frontonasal prominence
•PAIRED maxillary prominences
•PAIRED mandibular prominences
The nasal placode is part of the __________________. It is a thickened area of __________ that folds in on itself to ultimately form the _____________
The nasal placode is part of the frontonasal prominence. It is a thickened area of ectoderm that folds in on itself to ultimately form the nasal cavity
The invagination of the nasal placode forms 4 swellings called the __________________________________.
The invagination of the nasal placode forms swellings called the (paired) medial & lateral nasal prominence.
The medial nasal prominence forms the __________________________, _______________, ___________________ & ___________________
The medial nasal prominence forms the…
- tip & crest of the nose,
- nasal septum,
- philtrum of the upper lipid,
- primary palate
The lateral nasal prominence forms the……….
Sides of the nose called the nasal alae
What structures does the maxillary prominences form
What structures does the mandibular prominences form
What prominences make up the nose
Nasal bridge - frontonasal prominence
Nasal septum - medial nasal prominences
Nasal crest & tip - medial nasal prominences
Nasal alae - lateral nasal prominences
What prominences make the lip
Upper lip - maxillary & medial nasal prominences
Lower lip - mandibular prominences
What prominences make up the palate
Maxillary segment (majority) - Maxillary prominences
Intermaxillary segment (anterior) - Medial nasal prominences
What is the nasolacrimal groove
What are the three portions in the palate
Labial (anterior), upper dentition, palate (posterior) portion
What part of the palate fails to fuse in a unilateral palate defect extending into the nose
What part of the palate fails to fuse in a unilateral palate defect Involving the lip & nose
What part of the palate fails to fuse in a bilateral palate defect involving the cleft & nose
What part of the palate fails to fuse in an isolated cleft palate defect
What part of the palate fails to fuse in a cleft palate combined with unilateral anterior cleft lip defect
What membrane breaks down the week 6 to allow communication between the oral cavity & nasal pit
Oronasal membrane
Nasal cavity development
1) nasal placode =>
2) forms nasal pit =>
3) breakdown of oronasal membrane =>
4) forms primitive choana (connection with oral cavity) =>
5) forms definitive choana
Palate development summary
palatine shelves of the maxillary prominence grow downwards then elevate before fusing with each other
they then fuse anteriorly with the primary palate of the medial nasal prominence
