W2 Embryology facial structures Flashcards
Define Stomatodeum membrane
Formed by invagination of ectoderm tissues (noticeable by the end of the third week)
Define Oropharyngeal membrane
Composed of ectoderm and endoderm, itseparates the foregut from the stomodeum
Describe the formation of the face, referring to the frontal, maxillary and mandibular processes, the development of the nose, lip and angle of mouth
Fusion of all process:
The upper lip - result of fusion between maxillary and globular processes; the lip is fused at 8 weeks.
Angle of the mouth: forms as a result of fusion of the maxillary and mandibular processes
Mandibular arch - result of both mandibular processes fusing together.
What is Rathke’s pouch?
Invagination of stomodeal ectoderm in the roof of the stomodeum that moves towards the base of the brain eventually becoming the anterior lobe of the pituitary gland.
Describe the formation of the palate
Development of the palate can be divided into primary and secondary palate.
Palatal processes branch off the maxillary process and grow inferiorly along the developing tongue.
When the tongue drops into the floor of the mouth the palatal shelves elevate to a horizontal position.
Describe how the multiple nerve innervation of the tongue has embryological origins
Multiple pharyngeal arches contribute towards the formation of tongue resulting in mixed innervation.
- Anterior 2/3 of the tongue: Cranial Nerve V Cranial nerve VII Posterior 1/3 of the tongue: Cranial nerve IX - sensory and taste
- Motor supply to the whole tongue: cranial nerve XII
What is the medial nasal process?
The medial nasal processes merge with the maxillary prominences.
At it’s lower border, the median nasal process grows in length and produces a pair of bulges called the globular process. This grows downward (philtrum) and the anterior part of the palate.
What is the primary palate?
Horizontal shelf separating nasal pits from stomodeum, continuous with primitive. Made up of 4 incisor teeth
What is the secondary palate?
Secondary: shelf like out growths from maxillary process (palatine process). Canine and posterior teeth
What is the secondary palate?
Secondary: shelf like out growths from maxillary process (palatine process). Canine and posterior teeth
What is Macrostomia?
Larger than normal mouth. Cause: Incomplete fusion between maxillary and mandibular process. This can be unilateral or bilateral. In some cases can be corrected by surgery
What is Median cleft/cleft chin?
Result pf incomplete fusion of mandibular processes as they come together at the midline
Describe cleft clip
Due to failure of fusion of maxillary and globular processes, can be unilateral or bilateral
Describe cleft palate
Occurs if fusion does not take place between the palatine process (or both and the median nasal process, creating an opening between nasal or oral cavities.
Describe cleft palate
Occurs if fusion does not take place between the palatine process (or both and the median nasal process, creating an opening between nasal or oral cavities.
Describe ankyloglossia
A short lingual frenum 4%-11% of newborns; difficult for breast feeding
Describe Bifurcation
Lingual swelling of the first branchial arch have failed to merge
What do the 5 pharyngeal arches contain?
An artery, artilage, cranial nerve and mesodermal tissues.
Arches 1-4 involved in development of face and oral cavity structures
Describe 1st pharyngeal/branchial arch
It is the mandibular arch formed by fusion of maxillary process and mandibular process. It has trigeminal nerve and muscles of mastication
Describe the 2nd pharyngeal arch
The hyoid arch, it has the facial nerve and muscles of facial expression
Describe the 3rd paryngeal arch
It has the Glossopharyngeal nerve and stlopharyneus muscle
Describe the frontal process
Large bulge of ectoderm and mesoderm forming above the stomatodeum/stomodeum forming upper part of face, nasal septum and anterior palate.
Lower part is divided into 3 section:
- 2 Lateral nasal
- 1 median nasal process (forming the tip of npse, primary palate and nasal septum)
Describe the median nasal process
It grows in length producing pair of bulges (GLOBULAR PROCESS) this grows downward below olfactory puts to form the centre of lip (philtrum) and anterior portion of the palate (primary palate)
What (2) nerve supplies the anterior 2/3 of the tongue?
(V) Trigeminal: general sensory
(VII) Facial nerve: taste
What nerve supplies the posterior 1/3 of the tongue?
(IX) Glossopharyngeal: general sensory and taste
What nerve supplies motor innervation to the WHOLE tongue?
(XII) Hypoglossal nerve
