T3 Resp, Digest, Pharynx Flashcards
How many pairs of pharyngeal arches are there?
6
How many pairs of pharyngeal arches do humans have?
4
Describe the structure of a pharyngeal arch.
core of mesenchyme that is covered with ectoderm and lined with endoderm.
What is the main organizer for the development of the pharyngeal arch?
foregut ectoderm
The first pharyngeal arch develops _______ of Hox expression
independently
Pharyngeal arches II and II require the expression of what genes?
Hoxa2 and Hoxa3
Pharyngeal endoderm expresses TBx-1 that induces what to form the pharyngeal arches?
FGF8
The mandibular arch and associated trigeminal nerve (CN V) are associated with what pharyngeal arch?
first
What is the main component of the embryonic lower jaw?
Meckel’s cartilage
Meckel's cartilage gives rise to which of the following? A. sphenomandibular ligament B. malleus C. incus D. all of the above
all,
sphenomandibular ligament
malleus
incus
Hyoid arch, which is associated with the facial nerve (CN VIII), is what pharyngeal arch?
second
Development of the second pharyngeal arch is influenced by what gene?
Hoxa2
What nerves are the third and fourth pharyngeal arches associated with?
glossopharyngeal (CN IX) and vagus (CN X)
What structure is formed from the first pharyngeal groove?
external auditory meatus
What structure is formed from the second and third pharyngeal grooves?
cervical sinus, which is temporary
What are the derivatives of the first pouch?
tympanic cavity of middle ear and auditory tube
What are the derivatives of the second pouch?
fossa for palatine tonsils
What are the derivatives of the third pouch?
inferior parathyroids (in response to high concentrations of shh) and thymus (in response to high concentrations of BMP4).
What are the derivatives of the fourth pouch?
superior parathyroid and post-branchial body
The thyroid anlage is induced via signals from the underlying ________.
mesenchyme
The thyroid anlage grows down into the underlying mesenchyme as the _________________, which remains connected to the floor of the pharynx via the thyroglossal duct, which persists as a small pit at the base of the tongue, called the _______________.
thyroid diverticulum; foramen cecum.
What does the infundibular process form?
the neurohypophysis (posterior pituitary)
Where are the lateral lingual swellings located?
ventral areas of first pair of pharyngeal arches
Where is the tuberculum impar located?
ventral swellings between first and second pairs of arches
Where is the copula located?
ventral swellings between second and third pairs of arches
What is micrognathia?
small mandible
What is Agnathia?
the failure of the lower jaw to form
What is Treacher Collins syndrome?
Autosomal dominant, TCOF1 gene. Effects the survival and proliferation of cranial neural crest cells. In mutations of this gene, neural crest cell migration is normal but there is increases apoptosis and decreased proliferation, resulting in a reduced population of neural crest cells in the first pharyngeal arch.
What are pharyngeal cysts, sinuses, and fistulas?
Structural malformations, such as lateral cysts, sinuses and fistulas, can be related directly to the abnormal persistence of pharyngeal grooves, pouches, or both.
What is ankyloglossia?
Most common malformation of the tongue. Caused by subnormal regression of the frenulum, the thin midline tissue that connects the ventral surface of the tongue to the floor of the mouth
What is DiGeorge’s syndrome?
Cranial neural crest deficiency and is manifested by immunological defects and hypoparathyroidism. Failure of differentiation of thymus and parathyroid glands
What are the TF that control patterning of the anterior and posterior gut?
nodal (anterior) and FGF4 (posterior)
What controls the patterning of the foregut?
Wnt
What does the foregut express?
Sox2, Hhex, Foxa2
Where is the strong expression of FGF4?
near the foregut-midgut boundary
What TF repress foregut and maintain hindgut?
FGFs, BMPs, Wnts, and RA
What is the function of cdx2 in patterning of gut?
Hox gene expression in midgut and hindgut
What is the function of pdx1 in patterning of gut?
Sets apart midgut
What is the function of FGF10 in patterning of gut?
Establishes cecum
Where is the smooth muscle of the esophagus derived?
splanchnic mesoderm
Where is the skeletal muscle of the esophagus derived?
paraxial mesoderm
What is a pharyngeal cyst?
completely enclosed, epithelially lined cavity that may be derived from the persistence of part of a pharyngeal pouch, groove, or cervical sinus
What is a pharyngeal sinus?
closed on one end and open to the outside or to the pharynx
What is a pharyngeal fistula?
epithelially lined tube that is open at both ends
