Oral Cavity, Pharynx, and Larynx Flashcards
What is the origin of the anterior two-thirds of tongue?
stomodeum - ectoderm
What are the two components of the anterior two-thirds of tongue and their origins?
Median tongue bud - tuberculum impar
Distal tongue buds - lateral lingual swellings
Which cranial nerves contribute to the general sensation of the tongue?
Mandibular division of trigeminal nerve (V3)
Which cranial nerve contributes to taste and autonomics of the tongue?
chorda tympani nerve (branch of facial nerve VII)
Where does the posterior one-third of the tongue originate from?
pharynx - endoderm
Which structure makes up the posterior one-third of the tongue?
hypobranchial eminence
Which cranial nerve contributes to the hypobranchial eminence (posterior one-third of tongue)
glossopharyngeal nerve (IX)
Different mucosa tissue sources means…
multiple nerves innervate the tongue
Lingual papillae
small structures on the surface of the tongue that gives it its texture. There are four types.
What are the four types of lingual papillae?
circumvallate, foliate, fungiform, and filiform
Filiform papillae function
Most numerous papillae, responsible for the touch sensation, mechanical, and do not contain taste buds
Fungiform papillae - function and cranial nerve
They contain taste buds and are innervated by facial nerve (CN VII)
Circumvallate papillae - function and cranial nerve
taste and glossopharyngeal (CN IX)
Foliate papillae - function and cranial nerve
Taste and glossopharyngeal (CN IX)
How do muscles in the tongue form?
Myoblasts from occipital somites migrate into the tongue after the 5th week, and hypoglossal nerves trail the myoblasts and innervates the muscles
Muscular tissue in tongue - innervation
hypoglossal (CN XII)
Epiglottis - innervation
Vagus (CN X) sensory and taste innervation
Endoderm tissue of tongue (posterior 1/3 of mucosa) - innervation
Glossopharyngeal (CN IX) sensory and taste innervation
Anterior 2/3 of tongue - innervation
Facial nerve (CN VII - chorda tympani division)
Ectoderm tissue of tongue - innervation
Trigeminal nerve
Pharyngeal arch 1 - intermediate structures and adult structure of tongue
medial tongue bud -> replaced with lateral lingual swellings
Lateral lingual swellings -> mucosa of anterior two thirds of tongue
Pharyngeal arch 2 - intermediate structure and adult structure of tongue
copula -> overgrown by other structures
Pharyngeal arch 3 - intermediate structure and adult structure of tongue
ventral part of hypopharyngeal eminence -> mucosa of most of posterior one third of tongue
Pharyngeal arch 4 - intermediate structure and adult structure of tongue
dorsal part of hypopharygeal eminence -> mucosa of dorsal region of tongue
Occipital somites - intermediate structure and adult structures of tongue
myoblasts -> intrinsic muscles of tongue & palatoglossus muscle
Congenital lingual cyst
remnant of thyroglossal duct
Congenital lingual fistula
persistence of thyroglossal duct opening at foramen cecum
lingual thyroid
accounts for 90% of ectopic thyroids
Fissuring of the tongue
grooves in the dorsum of the tongue
Hypertrophic lingual papillae
hypertrophy of filiform papillae on dorsal surface of tongue, usually caused by lack of mechanical stimulation and debridement.
When do salivary glands develop in embryo?
three pairs of glands develop during 6th and 7th week
How do saliva glands start out in development?
solid epithelial buds from the primitive oral cavity
Epithelial buds branch into surrounding ___________ to form gland
mesenchyme
secretory epithelium develops from
oral epithelium
capsule and connective tissue develops from
mesenchyme
What are the three pairs of salivary glands?
parotid glands, submandibular glands, and sublingual glands
How do parotid glands develop
as paired buds from oral ectoderm of stomodeum, grow towards ears
How do submandibular glands develop
as paired buts from endoderm of oral cavity, grow posteriorly and lateral to tongue
how do sublingual glands develop?
as multiple buds from endoderm of oral cavity, form 10-12 ducts that open independently into floor of mouth
Primary dentition
20 deciduous baby teeth, shed throughout childhood
secondary dentition
32 permanent teeth
Both deciduous and permanent teeth begin developing ________
prenatally
When do 3rd molar (wisdom teeth) develop?
begins to develop after birth, finishes development around 12 years
Why is tooth development key to normal jaw growth?
growth of mandible and maxilla occur to accommodate teeth and it changes the shape of your face
Dental lamina forms in the
ectodermal epithelium of the mandible and maxila
each dental lamina gives rise to
10 tooth buds (10 per jaw)
Tooth buds form a cap around condensing neural crest, forming the
dental papillae
odontoblasts develop from _____ _____ and produce ______
neural crest; dentin
ameloblasts develop from _____ and produce _______
ectoderm; enamel
what are the stages of tooth development
bud stage - 8 weeks
cap stage - 10 weeks
bell stage - 3 months
maturation (crown stage)
cementoblasts develop from ______ ______ _____ and deposit
neural crest cells; cementum around root
Periodontal ligament
forms outside of the cementum to anchor the tooth in position
Enamel hypoplasia
thin or absent enamel
causes of enamel hypoplasia
nutritional deficiency pre or postnatally, tetracycline use during pregnancy, and rickets
CN V2,V3 innervates in oral cavity
mucous membranes of nasal cavities, palate, mouth, and tongue
CN VII innervates in tongue
special sensory fibers (taste) to anterior 2/3 of tongue
CN IX innervates in tongue
mucous membranes of posterior 1/3rd of tongue and upper pharynx, special sensory fibers (taste) to posterior 1/3rd of tongue
CN X innervates in oral cavity
mucous membranes of lower pharynx and larynx, special sensory fibers (taste) to epiglottis
arytenoid swellings differentiate into
arytenoid and corniculate cartilages
arytenoid swellings differentiate into
arytenoid and corniculate cartilages
when and where do arytenoid swellings appear
at 32 days gestation, and they appear in the sixth arch adjacent to laryngotracheal tube
Hypobranchial eminence gives rise to
epiglottis and cuneiform cartilages
Thyroid cartilage comes from which branchial arch?
4th
Cricoid and tracheal cartilages develop from which branchial arch?
6th
