Pharyngeal Arches Flashcards
What type of cells are the PA derived from?
Mesenchyme
Early in the 4th week, how much of the embryo does the H and N represent?
Half
What cell lineage do P pouches come from?
Endoderm
What do the P pouches dev into?
Middle ear, parathyroid glands, thymus and palatine tonsils
Where does the pharynx extend from/to?
Base of skull to inf boarder of cricoid cartilage of the larynx
Which type of cells are critical to the dev of the H and N?
Neural crest cells
What does each PA consist of?
Cranial nerve, artery, cartilaginous bar
What thickens to fold and create the neural tube?
Overlying ectoderm
Ant NT forms the forebrain, midbrain, hindbrain. What are each vesicle stage known as?
Prosencephalon, mesencephalon, rhombencephalon
What are the nerves of the PA?
5 (trigeminal), 7 (facial), 9 (glossopharyngeal), 10 (vagus)
What is the facial skeleton derived from?
FNP and 1st PA
Which arch are the muscles of mastication and facial expression derived from?
1st PA and 2nd PA respectively
Which muscle is derived from the 3rd PA?
Stylopharyngeus
Which muscles are derived from the 4th PA?
Cricothyroid, levator palatini, constrictors of the pharynx
Which muscles are derived from PA 6?
Intrinsic muscles of the larynx
Which PA does the trigeminal nerve come from?
1st
Which PA does the facial nerve come from?
2nd
Which PA does the glossopharyngeal nerve come from?
3rd
Which PA’s do parts of the vagus nerve come from?
4th- sup laryngeal, 6th- recurrent laryngeal
What are the neural crest- derived cartilage bars for PA 1 and 2 called? What do they both create?
PA1- Meckel’s- maxillary and mandibular prominences, malleus, incus
PA2- Reichert’s- middle ear (stapes), styloid process, hyoid bone
What do the PA cartilage bars of PA 4 and 6 create?
Cartilages of the larynx
What happens to the first and second aortic arches?
They disappear
What does the 3rd aortic arch form?
ICA
What does the 4th aortic arch form?
L- arch of aorta, R- brachocephalic
