Lecture 31 - Craniofacial Development and Malformations Flashcards
What is the name of the tissue covering the cranial forebrain?
frontonasal prominence
Ba1, the largest branchial arch, consists of what two prominences?
- Maxillary prominence
2. Mandibular prominence
The stomodeum is a depression that is continuous internally with the cranial end of the foregut. It corresponds to the:
mouth, anterior oral cavity
What areas of surface ectoderm ultimately give rise to the lens, the inner ear, and the nasal epithelium?
ectodermal placodes
Bilateral and unilateral cleft upper lip may result if superficial portions of the _______ and _______ do not fuse appropriately.
medial nasal and maxillary prominences
Which of the following structures is not derived from branchial arch 1?
A. Maxilla B. Mandible C. Incus D. Malleus E. Stapes
E. The stapes is derived from branchial arch 2.
Branchial arch 3 gives rise to the ________ muscle.
stylopharngeus muscle
Anterior cleft palate refers to a failure of fusion of the ______(a)______ with the ______(b)______.
a) medial palatine process
b) lateral palatine shelf
Shh is initially produced by the _______ and ________.
notochord and prechordal mesoderm
Which molecule originates from the lateral mesoderm?
A. Shh
B. RA
C. TCOF1
D. Tbx1
B.
A patient presenting with underdevelopment of face, thymus defects, microcephaly, and neural tube defects. Which is most likely NOT responsible?
A. RN signaling that alters expression of Hox genes
B. Diminished 22q11 dosage via expression of RA-regulated genes
C. Suppression of Shh by ectopic RA
B. This is characteristic of DiGeorge/Velo-cardio-facial syndrome.
Which cranio-facial syndrome features abnormal calcium regulation associated with hypoplasia of the parathyroid and thyroid glands?
DiGeorge/Vel-cardio-facial syndrome
DiGeorge’s syndrome, in which patients have microdeletions of 22q11, is believed to be caused by haploinsufficiency of one or more genes on 22q11, most prominently _____.
Tbx1
A patient presents with hypoplasia of the mandible and facial bones, as well as malformations of external and middle ears. You determine that 1st and 2nd arch crest development has been disrupted, and thus the _____ gene signaling is likely involved.
TCOF1
What plays a critical role in patterning the hindbrain?
RA signaling
Which is NOT innervated by the trigeminal nerve?
A. Muscles of mastication B. Ventral mylohyoid C. Anterior belly of digastric D. Posterior belly of digastric E. Tensor tympani
D. The posterior belly of the digastric is innervated by the facial nerve (CN VII).
What neural crest derivative is innervated by the glosspharyngeal nerve (CNIX)?
Lower hyoid bone
What neural crest derivative is innervated by the vagus nerve (CNX)?
Laryngeal cartilage
The upper hyoid bone is innervated by the ______.
Facial nerve (CNVII)
Which muscle is not innervated by the vagus nerve (CNX)?
A. Soft palate
B. Pharyngeal muscles
C. Stylohyoid muscle
D. Laryngeal muscles
C. The stylohyoid muscle is innervated by the facial nerve (CNVII).
The stapedius muscle is innervated by:
A. CN V - Trigeminal
B. CN VII - Facial
C. CN IX - Glossopharyngeal
D. CN X - Vagus
B.
Pharyngeal pouches come from what germ layer?
Endoderm - gives rise to lining of primitive gut tube, including “outpockets” such as the pharyngeal pouches.
The ear is derived from what structures?
1st and 2nd branchial arches
Children with DiGeorge Syndrome often display hypoplasia of the thymus gland. What is the endodermal derivative (i.e. pharyngeal pouch) is the thymus derived?
A. Pouch 1 B. Pouch 2 C. Pouch 3 D. Pouch 4 E. Pouch 5
C. The thymus and inferior parathyroids are derived from pouch 3.
The endodermal derivative of the thyroid, which migrates ventrally during development, is the __________.
Ventral midline diverticulum
Hypoplasia of the 3rd and 4th branchial arch derivatives during development can lead to hypoplasia of the hyoid, immunodeficiency, and hypoparathyroidism. What syndrome is being described?
DiGeorge’s syndrome (Velo-cardio-facial)
Which facial prominence is NOT derived from 1st arch neural crest mesenchyme?
The frontonasal prominence is derived from the cranial neural crest mesenchyme.
Children with fetal alcohol syndrome often display a smooth philtrum of the upper lip. This structure is derived from the:
A. Frontonasal prominence B. Medial nasal prominence C. Lateral nasal prominence D. Mandibular prominence E. Maxillary prominence
B. The medial nasal prominence (process) gives rise to the midline of the nose and the philtrum of the upper lip.
The cheeks and lateral upper lip are derived from the:
A. Frontonasal prominence B. Medial nasal prominence C. Lateral nasal prominence D. Mandibular prominence E. Maxillary prominence
E.
The lower lip and jaw are derived from the:
A. Frontonasal prominence B. Medial nasal prominence C. Lateral nasal prominence D. Mandibular prominence E. Maxillary prominence
D.
Anterior cleft palate refers to a failure of fusion of the ___________ with _____________.
A. Medial palatine process; medial palatine process
B. Medial nasal process; lateral nasal process
C. Medial palatine process; lateral palatine shelf
D. Lateral palatine shelf; lateral palatine shelf
C.
Posterior cleft palate refers to a failure of fusion of the __________ with _________.
A. Medial palatine process; medial palatine process
B. Medial nasal process; lateral nasal process
C. Medial palatine process; lateral palatine shelf
D. Lateral palatine shelf; lateral palatine shelf
D.
The secondary or posterior palate originates from the ____________ as lateral or secondary palatal shelves.
medial aspects of the maxillary prominences
The primary or anterior palate originates from the ____________.
medial nasal process
The transcription factors affected by Shh signaling are members of the ______ family.
Gli
Sonic hedgehog (Shh) plays a role in inducing forebrain development when it is expressed in the __________.
A. Pharynx B. Head ectoderm C. Prechordal mesoderm D. Pharyngeal endoderm E. Pharyngeal mesoderm
C. Alterations in Shh forebrain development are relevant to the disorder Holoprosencephaly.
Shh plays a role in neural crest proliferation when it is expressed in the __________.
A. Zone of polarizing activity B. Head ectoderm C. Prechordal mesoderm D. Pharyngeal endoderm E. Pharyngeal mesoderm
B. Additionally, Shh affects neural crest proliferation in the pharynx.
Shh plays a role in mesoderm expansion when it is expressed in the __________.
A. Zone of polarizing activity B. Head ectoderm C. Prechordal mesoderm D. Pharyngeal endoderm E. Pharyngeal mesoderm
A. Aside from mesoderm expansion, Shh expressed in the ZPA is responsible for AP patterning of the limb.
Exposure to excess RA may have an affect by suppressing ______ signaling in the head.
Shh.
Fetal Retinoid Syndrome causes underdevelopment of face (Shh is important in late stages of facial expression).
Which symptom is NOT a primary result of excess exposure to retinoids in utero - regarding HOX expression?
A. Mispatterning of the hindbrain
B. Problems in branchial arch development
C. Interference in late stages of facial development.
C. This is due to RA suppression of Shh.
RA regulation of Hox expression defines hindbrain areas.
RA also ectopically activates Hox genes to alter patterns crest cells/branchial arches.
You determine that two particular branchial arches have been affected by observing malformations of the external and middle ears, as well as hypoplasia of the mandible. What gene might be responsible for the arch/crest development of these regions?
TCOF1 - causes extensive cranial neural crest cell death among populations that migrate into the 1st and 2nd arches. (e.g. Treacher Collins Syndrome)
Tbx1 plays a role in the development of which specific pouch(es)?
Pouch 3 and 4 (seen in 22q11 deletion)
Fetal alcohol syndrome is a series of abnormalities that have been linked to excessive alcohol consumption by the mother during pregnancy. A major site of disruption appears to be:
A. first branchial arch
B. induction of pharyngeal pouch structures
C. induction of cardiac mesoderm
D. formation of midline craniofacial structures
E. second branchial arch
D.
