L01-2
What 2 factors are important for early head and neck formation (and in limb development)
Hox complex and retinoic acid
How do neural crest cells get transformed into the facial region?
BONUS: What do they form?
They migrate ventrally into pharyngeal arches and rostrally (towards the front of head) around forebrain and optic cup to the facial region
BONUS: forms the entire viscerocranium
Which of the following do not have taste buds present: filiform papillae, fungiform papillae, foliate papillae, circumvallate papillae
NO TASTE BUDS IN FILIFORM PAPILLAE
Where is the primary palate derived from?
inter maxillary segment
Abnormal migration of the thyroid can lead to_____. Which can also lead to remnants that persist along the tract causing ____.
ectopic thyroid (base of tongue most commonly), thyroglossal duct cyst
When is the pharyngeal apparatus first observed and what does it consist of?
BONUS: what else happens during the same week the pharyngeal apparatus is observed first?
1st seen in week 4; consists of pharyngeal arches, pouches, grooves, and membranes
BONUS: heartbeat begins and upper/lower limb bud formation
What becomes the parafollicular cells of the thyroid in the 4th arch?
The ultimobranchial body, which regulates calcitonin and calcium
What carries general sensation to the anterior 2/3 tongue? What nerve carries taste sensation? NERVE AND BRANCH!
Bonus: which pharyngeal arch gives rise to the anterior 2/3 tongue
General sensation: lingual branch of CN V
Taste: chorda tympani of CN VII; SVE neurons convey taste from tongue -> CNS (cell bodies for these are housed in the geniculate ganglion)
Bonus: pharyngeal arch 1
What are the contents of the mouth ectoderm?
epithelium of oral part of tongue, hard palate, sides of mouth, lips, parotid gland and ducts, Rathke pouch, and teeth enamel
When does the thyroid develop? Where does it arise from (germ layer and pouches)?
Which pharyngeal arch and pouch completely regress in humans?
Pharyngeal arch and pouch 5
At the end of the 4th week, the embryo has 5 face prominences. What are the 3 Dr. Harp mentioned and what arch are they associated with?
mandibular prominences (1st pharyngeal arch), maxillary prominences (1st pharyngeal arch dorsal portion), frontonasal prominence
In the posterior 1/3 of the tongue, what is the pharyngeal tongue characterized by and what nerve provides general and taste sensation from mucosa?
The pharyngeal tongue is characterizes by the lingual tonsil and the nerve is CN IX (glossopharyngeal)
What are the contents of the mouth endoderm?
Epithelium of pharyngeal part of tongue, floor of mouth, palatoglossal fold, palatopharyngeal fold, soft palate, sublingual gland and ducts, submandibular gland and ducts
DiGeorge syndrome is caused by a micro deletion in chromosome ____. It results in the failure of pharyngeal pouches __ and __ to differentiate into thymus and PTH glands.
22q11.2; pouches 3 and 4
Which pharyngeal arches contain somitomeric mesoderm and neural test cells? What do they differentiate to?
Tell me the cranial nerve associated with each pharyngeal arch
1st pharyngeal arch is the trigeminal nerve (3 branches), 2nd pharyngeal arch is the facial nerve, 3rd pharyngeal arch is the glossopharyngeal nerve, musculature of the 4th arch is the superior laryngeal branch of vagus nerve, musculature of 6th arch is the recurrent laryngeal branch of vagus nerve
What would be the outcome of the following sets of circumstances: abnormal fusion between lateral nasal and maxillary prominences AND failure of fusion between medial nasal prominence and maxillary prominence
no fusion in lateral nasal + maxillary prominences would result in a failure to form the nasolacrimal duct and lacrimal sac.
abnormal fusion of nasomedial and maxillary processes would result in cleft lip and palate
Which pharyngeal arch does the thymus come from?
3rd; the ventral pouch of the 3rd forms thymus
What is the failed fusion of palatine shelves called?
cleft palate
What are evaginations of endoderm including that which will line the foregut? What are invaginations of the ectoderm located between each pharyngeal arch?
Pharyngeal pouches (out pouching) 1-4; pharyngeal grooves 1-4
In this pharyngeal arch, it gives rise to the greater horn and lower portion of the body of the hyoid. It is associated with the glossopharyngeal nerve. The muscle from the arch allows us to have the pharyngeal phase of swallowing and dilates nasopharynx during breathing. What arch am I describing and what muscle is associated?
Pharyngeal arch 3- stylopharyngeus
What arch does the maxillary and mandibular prominence come from?
Pharyngeal arch 1
What are the contents of the nasal placode ectoderm? What nerve is associated?
Olfactory epithelium (contains sustenacular cells, basal cells, ciliated cells), ciliated cells are bipolar neurons that give rise to CN I
A child presents with a cleft palate involving lips, primary palate, and secondary palate. Is this unilateral or bilateral?
Bilateral;
Unilateral is defined as: extending into nose or involving lip and primary palate extending to incisive foramen