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35 Cards in this Set
- Front
- Back
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What is the thyroid diverticulum? |
Thickening of endoderm growing caudally midline of floor of ventral pharynx to eventually form the thyroid gland |
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What is the first endocrine gland to develop? |
Thyroid gland |
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What mature structure does the ventral pharynx eventually form? |
Tongue |
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What happens to the thyroid diverticulum? |
Forms thyroglossal duct Migrates down from pharynx into neck |
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What happens to the thyroglossal duct? |
Maintains connection to tongue Once thyroid diverticulum migrates down to neck, thyroglossal duct disappears |
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What is the remnant of the thyroglossal duct? |
Foramen cecum, groove or spot in tongue |
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Which of the 3 developmental tissues forms the thyroglossal duct? |
Endoderm |
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**What is the path of the thyroid gland? |
Foramen cecum of tongue to below thyroid cartilage (which is inferior to hyoid bone) |
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What is a pyramidal lobe? |
Thyroid tissue that didn't develop into one of the two normal lobes Not everyone has one |
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Where are thyroglossal duct cysts found? |
Anywhere along midline of ventral neck; from hyoid to thyroid |
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What are thyroglossal duct cysts? |
One of three discussed congenital anomalies of thyroid gland Most common congenital neck mass (fibrous connective tissue strap) Due to thyroglossal duct not disappearing after development |
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What is ectopic thyroid tissue? |
Second of three discussed congenital anomalies of thyroid gland Thyroid is abnormally located anywhere along migratory path rather than inferior to thyroid cartilage- may be patches of thyroid along the pathway Uncommon |
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What is congenital hypothyroidism? What is the cause? What is the symptom? Why does it matter thematically? |
Third of the three discussed congenital thyroid abnormalities Low thyroid hormones (T3/T4) Due to thyroid agenesis (didn't form), iodine deficiency, or mutated thyroid hormone biogenesis Results in cretinism- small stature, stocky, mentally deficient, sterile- underlines why thyroid development is so important |
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Which pharyngeal arch swellings develop the tongue (be specific about which arches and swellings lead to which tongue segments)? |
Arches 1-4 1-median lingual swelling and 2 lateral lingual swellings form ant. 2/3 of tongue 2-copola (midline swelling) forms taste to oral part of tongue- chorda tympani/facial n are involved in taste sensation 3 and 4-hypobranchial eminence forms pharyngeal part of tongue (post. 1/3)- glossopharyngeal (cn9) 4-epiglottis swelling forms epiglottis (cartilage) |
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What innervates each pharyngeal arch? What does each arch contribute to? |
1- gen sense, V2 (mandibular branch) 2- special sense (TASTE), chorda tympani of VII 1+2= ant. 2/3 (oral) of tongue 3- gen sense + taste, IX 4- gen sense, X 3+4= post. 1/3 (pharyngeal) of tongue ***4 or X also does general + special sense of epiglottis -motor inn. of intrinsic tongue m.- XII (occipital myotomes) |
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What do the 5 swellings of the first arch do? What are their names? |
Form around stomodeum to begin face development 1 frontonasal prominence- flexes posture 2 maxillary prominences (The above prominences grow from sides to middle) 2 mandibular prominences |
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What is the stomodeum? |
Hollowed out area in middle- most rostral/frontal part of duct |
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What is the oropharyngeal membrane, and what happens to it? |
Separates stomodeum from pharynx Ruptures in 4th week, allowing open connection between mouth and gi- allows swallowing |
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What are the respective developmental tissue layers of stomodeum and pharynx? |
Ectoderm and endoderm |
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Which facial prominences form the nose? |
5 Frontal (1), medial (2), and lateral nasal (2) |
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What is the facial difference between 5 and 6 weeks? |
Maxillary prominences grow towards ventral midline, forcing medial nasal prominences to grow together |
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**What is the intermaxillary segment, and what does it turn into? |
Midline embryonic structure fusing 2 medial nasal prominences Philtrum (labial), primary palate (palatal, and premaxilla (upper jaw, 4 incisors) |
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Where does the nasolacrimal groove form? What does it turn into? |
Between maxillary and lateral nasal prominences Nasolacrimal duct and lacrimal sac |
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What happens to mandibular prominences? |
Grows together to form mandible |
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What are their adult structures? |
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What is the palate made from? |
Primary and secondary palates Respectively intermaxillary segment and outgrowth of maxillary processes |
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What do the maxillary prominences turn into? |
Palatine processes/shelves-> secondary palate |
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What fuses with what to create the definitive palate? |
Palatine processes + primary palate |
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Where does the nasal septum come from? What does it do in the process? |
Grows down from frontonasal prominence to fuse with palate-> forms 2 nasal cavities |
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Primary and secondary palate are separated by what? |
Incisive foramen |
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What are 3 kinds of cleft lip? |
1.Groove btwn medial nasal prominence + maxillary process 2.Persistent labial groove- tissue breaks down btwn ext. And int. aspects of labial groove 3. Complete separation of processes |
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Definition of cleft lip and prevalance? |
Maxillary prominence fails to fuse with medial nasal prominences More in males, pretty common in general More rare for median clefts- fail to fuse medial nasal prominences (upper) and mandibular prominences (lower) with each other |
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2 kinds of cleft palate? |
Ant. Cleft malformation- problem with median palatine process of intermaxillary segment (primary palate)- complete = anterior cleft through lip and alveolar part of maxillary to incisive fossq Post. Cleft malformation- fail to fuse palatine processes/shelves of maxillary prominences + nasal septum (2ndary palate) |
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Cleft palate prevalence? Which gender has more and why? |
Rarer than cleft lip Higher in females- bc of lateral palatine processes fusing 1 week later than in males Occurs sometimes with/without cleft lip Higher in trisomy 13 and other chromosomal syndromes |
