Pharyngeal Arches/Tongue Flashcards
When does the pharyngeal apparatus begin to form?
4th week of development
What are the parts of the pharyngeal apparatus?
Pharyngeal arches
Pharyngeal pouches
Pharyngeal grooves
Pharyngeal membranes
What are pharyngeal pouches lined by?
Endoderm
What are pharyngeal grooves lined by?
Ectoderm
Where does the pharyngeal pouch meet the groove?
Pharyngeal membrane
What are the components of the pharyngeal arch?
Aortic arch
Cartilaginous rod
Muscular component
Nerve
What does the first pharyngeal arch form?
Maxillary prominence, mandibular prominence
What is the pharyngeal arch externally lined with?
Ectoderm
What is the pharyngeal arch internally lined with?
Endoderm
What is contained within an arch?
Mesenchyme
What membrane ruptures and forms the opening from the pharynx to the amniotic cavity?
Oropharyngeal membrane
What is the first arch cartilage derivative?
Malleus, incus, and Meckel’s cartilage
What is the second arch cartilage derivative?
Stapes, styloid process, and lesser horn of the hyoid bone
What is the third arch cartilage derivative?
Body, greater horn of the hyoid bone
What is the third and fourth arch derivative?
Epiglottis
What is the fourth and sixth arch derivative?
Laryngeal cartilages
What innervates the first arch?
Trigeminal nerve (CN V) -> mandibular division
What innervates the second arch?
Facial nerve (CN VII)
What innervates the third arch?
Glossopharyngeal nerve (CN IX)
What innervates the fourth and sixth arch?
Vagus nerve (CN X)
What muscles come from the first arch?
Muscles of mastication, mylohyoid and anterior belly of the digastric, tensor tympani, tensor veli palatini
What muscles come from the second arch?
Muscles of the facial expression, stapedius, stylohyoid, posterior belly of digastric
What muscles come from the third arch?
Stylopharyngeus
What muscles come from the fourth arch?
Palato muscles, pharyngeal muscles, cricothyroid
What muscles come from the sixth arch?
Laryngeal muscles, inferior pharyngeal constrictor, skeletal muscle of the esophagus
What comes from the first pharyngeal pouch?
Tympanic membrane and the pharyngotympanic tube
What comes from the second pharyngeal pouch?
Tonsillar fossa
What forms when the second pharyngeal pouch is obliterated?
Palatine tonsils
What comes from the third pharyngeal pouch?
Inferior parathyroid gland, thymus
What comes from the fourth pharyngeal pouch?
Superior part of parathyroid glands, ultimopharyngeal body
What comes from the pharyngeal groove?
External auditory meatus
In about 50% of individuals, what is a remnant that is present?
Thyroglossal duct
What occurs when there is a persistence of the pharyngeal grooves?
Brachial fistula/cyst
What is branchial vestiges?
Normally pharyngeal cartilages disappear; remnants of cartilage or bony elements under the skin anterior to the inferior 1/3 of the sternocleidomastoid persist
What is ectopic thyroid tissue?
The thyroid gland undergoes a migration from the oral cavity to the neck region. It is common for remnants of thyroid tissue to remain along the course of migration. The parathyroids also undergo a migration and are highly variable in their location
What are thyroglossal cysts & sinuses?
Tubular remnant of thyroglossal duct, lies in midline of neck
What are the neural crest cells defects?
Treacher Collins syndrome, Pierre Robin Sequence, DiGeorge Anomaly, Goldehar syndrome
Treacher Collins syndrome
Malformed external ears, downward slanting palpebral fissures, malar/mandibular hypoplasia
What is first arch syndrome?
Treacher Collins syndrome
What is Pierre Robin Sequence?
Involves first arch
Micrignathia
Cleft palate
External ear defects
What is DiGeorge Anomaly?
Involves abnormalities of the heart, parathyroid gland, face, and thymus gland (the degree to which the immune system is affected varies). Affected individuals will have
congenital heart disease, unusual facial features with low-set ears, a small receding mandible, wide-set eyes and are born without parathyroid glands
What is Goldehar syndrome?
abnormal development of 1st and 2nd pharyngeal arches
characteristic features include microtia, mandibular hypoplasia, microstomia, skin tags and vertebral anomalies
What are most of the tongue muscles derived from?
Occipital somites
What are the occipital somites accompined with?
Hypoglossal nerve
What is the somatic sensation of the anterior 2/3 of the tongue innervated by?
Vagus nerve (cranial nerve X)
What is the visceral sensation of the anterior 2/3 of the tongue innervated by?
Facial nerve (cranial nerve VII)
What is the sensory posterior 1/3 of the tongue innervated by?
Spinal accessory nerve (cranial nerve CN IX)
What does cranial nerve X supply?
