Embryology Flashcards
how many pharyngeal arches are there
5
what are pharyngeal arches
projections of proliferating mesoderm coming from the neck region of the developing embryo
what is associated with each pharyngeal arch
artery, cranial nerve and cartilage
what nerve is associated with pharyngeal arch 1
trigeminal
what nerve is associated with pharyngeal arch 2
facial
what nerve is associated with pharyngeal arch 3
glossopharyngeal
what nerve is associated with pharyngeal arch 4
vagus
what nerve is associated with pharyngeal arch 6
hypoglossal
what does the cartilage associated with pharyngeal arch 1 develop into
incus, malleus and template for the mandible
what does the cartilage associated with pharyngeal arch 2 develop into
middle ear bones and part of the hyoid bone
what does the cartilage associated with pharyngeal arch 3 develop into
part of the hyoid bone
what does the cartilage associated with pharyngeal arch 4 develop into
larynx cartilage
what does the cartilage associated with pharyngeal arch 6 develop into
larynx cartilage
describe what happens to the aortic arches in development
the first 2 degree
3rd = internal carotid
4th = arch of aorta (L) and brachiocephalic (R)
6 = pulmonary arch
what is the mesoderm derivative of pharyngeal arch 1
muscles of mastication
what is the mesoderm derivative of pharyngeal arch 2
muscles of facial expression
what is the mesoderm derivative of pharyngeal arch 3
stylopharyngeus muscle in the head
what is the mesoderm derivative of pharyngeal arch 4
constrictors or pharynx, cricothyroid muscle and levator palatini
what is the mesoderm derivative of pharyngeal arch 6
larynx muscles
what is the name of the 1st pharyngeal pouch
tympanic cavity
what do the pharyngeal pouches develop into
palatine tonsils, parathyroid glands, thymus
what does the 1st pharyngeal cleft develop into
external auditory meatus
what is the stomatodeum
the space between the frontonasal prominence and 1st pharyngeal arch that will become the oral cavity
in the development of the face, what will derive from the FNP
forehead, bridge or nose, philtrum
in the development of the face, what will derive from the the maxillary part of the 1st arch
cheek, upper lateral lip, lateral upper jaw
in the development of the face, what will derive from the mandibular part of the 1st arch
lower lip and jaw
what does the 1st pharyngeal pouch develop into
the small bones of the ears (ossicles) and the middle ear
describe the development of the nose
the nasal placoderms sink in to become nasal pits - these are surrounded by medial and lateral nasal prominences
the maximally prominence then grows medially pushing the 2 medial nasal prominences together which fuse to form the intermaxillary segment
the maxillary prominences are known as the palatal shelves and these also fuse together to form the palate
what is lateral cleft lip
where the medial nasal prominences fail to fuse
what is cleft lip and cleft palate
where the medial nasal prominences and the palatal shelves fail to fuse
what type of tissue does the infundibulum develop from
neurectoderm
what does the infundibulum develop into
posterior pituitary gland
what type of tissue does Rathke’s pouch develop from
ectoderm
what does Rathke’s pouch develop into
anterior pituitary gland
where does the thyroid gland start developing from
at the foramen caecum at the base of the tongue
what duct does the thyroid gland move down
the thryoglossal duct
what can form if the thyroglossal duct doesn’t fully degenerate
thryoglossal cysts fistuales
which pharyngeal arches contribute to the tongue
all 5 of the arches
name the areas of the pharyngeal arches which make up the tongue
1 - lateral lingual swellings and Tuberculum impar
2 and 3 - cupola
4- epiglottal swelling
describe the growth of the pharyngeal arches to give the tongue
the lateral lingual swellings and cupola overgrow the Tuberculum impar so that the 2nd arch no longer forms part of the tongue
what is the only attachment of the tongue to the base of the oral cavity
lingual frenulum
what nerve supplies the taste buds
chorda tympani branch of the facial nerve
what migrates to the tongue to form the intrinsic and extrinsic tongue muscles and what nerve is associated with this
occipital somites which are associated with CN XII
what is Treacher Collins syndrome
where neural crest cells fail to migrate to the 1st pharyngeal arch
what are the consequences of Treacher Collins syndrome
hypoplasia of the mandible and facial bones
what is Di-Georges syndrome
failure of the neural crest cells to develop in the 3rd and 4th pharyngeal arches
what are the consequences of Di-Georges syndrome
immunodeficiency - due to hypoplasia of the thymus so little T cell maturation
hypocalceamia - due to absence of parathyroid glands
what is charge syndrome
where neural crest cells abnormally differentiate to become multipotent
