Embryology Flashcards
How much of the embryo at week 4 will be the future head and neck?
1/2
What is a pharyngeal arch?
Mesenchymal proliferations in the neck region of the embryo
How many pharyngeal arches are there?
5 (1-4 and 6)
What is the structure that will later form the nose called?
Frontonasal prominence
Which cranial nerves are associated with the pharyngeal arches?
5,7,9,10
Which muscles are derived from the 1st pharyngeal arch?
Muscles of Mastication
Which muscles are derived from the 2nd pharyngeal arch?
Muscles of Facial expression
What does the cartilage bar from the 1st pharyngeal arch form?
Malleus, incus and template for the mandible. Meckel’s.
What does the cartilage bar from the 2nd pharyngeal arch form?
Stapes and upper part of hyoid bone. Reichert’s.
What does the cartilage bar from the 3rd pharyngeal arch form?
The remainder of the hyoid bone
What do the cartilage bars from the 4th and 6th pharyngeal arches form?
Cartilage of the larynx
What happens to the 1st and 2nd arch arteries in forming the aorta and its branches?
They disappear
Which arch artery forms the arch of the aorta?
4th arch artery
Pharyngeal pouch vs cleft?
Pouch is the dip in endoderm, the cleft is on the outside in ectoderm
What does the 1st pharyngeal pouch become?
Tympanic cavity
What happens to the pharygeal clefts?
Only the 1st one remains becoming the external acoustic meatus, the 2nd arch grows downwards covering the other clefts
Name 2 pathologies that can occur if there are remnants of the pharangeal clefts?
Branchial cyst/fistula
What drives the development of the face?
Expansion of the cranial neural tube
What is the stomatodeum?
A depression in the middle of the face that will later become the mouth, covered by buccopharyngeal membrane
What are the nasal placodes?
Form on the frontonasal prominence, and sink to become nasal pits
How is the secondary palate formed?
Maxillary prominence gives rise to 2 palatal shelve that grow together and downwards on each side of the developing tongue
How is the primary palate formed?
Fusion of the medial nasal prominences create the intermaxillary segment. Contains the philtrum, 4 insisors and primary palate
Which cleft does the external auditory meatus come from?
1st
What is the path of the external ear to the standard anatomical position?
Develop initially on the neck, as the mandible grows the ear ascends to the sides of the head.
