Embryology 1 Flashcards
(22 cards)
What are pharyngeal arches
System of mesenchymal proliferations in neck region (ectoderm, mesoderm and endoderm)
Role of neural crest cells in development of pharyngeal arches
Migrate into mesoderm core to influence development of arches
What does each pharyngeal arch develop into
Muscular component
Cartilage bar
Cranial nerve
Aortic arch
What are pharyngeal pouches and clefts
Pouch - between each arch on endoderm side
Cleft - between each arch in ectoderm side
What do the anterior and posterior parts of the neural tube become
Anterior - forebrain, midbrain and hindbrain
Posterior - spinal cord
Which cranial nerve develops from the 1st pharyngeal arch
What does it innervate
Trigeminal
Sensory - skin of face and lining of nose and mouth
Motor - muscles of mastication
Which cranial nerve develops from the 2nd pharyngeal arch
What does it innervate
Facial
Sensory - taste buds in anterior 2/3 tongue
Motor - muscles of facial expression
Which cranial nerve develops from the 3rd pharyngeal arch
What does it innervate
Glossopharyngeal
Sensory - taste buds in posterior 1/3 tongue
Motor - stylopharyngeus
Which cranial nerve develops from the 4th pharyngeal arch
What does it innervate
Superior laryngeal branch of vagus
Motor - pharyngeal constrictors and cricothyroid
Which cranial nerve develops from the 6th pharyngeal arch
What does it innervate
Recurrent laryngeal branch of vagus
Motor - intrinsic muscles of larynx
Which cartilage develops from the 1st pharyngeal arch
What does it become
Meckel’s cartilage (mandibular prominence only)
Malleus, incus and mandible
Which cartilage develops from the 2nd pharyngeal arch
What does it become
Reichart’s cartilage
Stapes, styloid process and part of hyoid (lesser Cornu and upper body)
Which cartilage develops from the 1st pharyngeal arch
Forms rest of hyoid
Which cartilage develops from the 4th pharyngeal arch
Thyroid and cricoid cartilage
Which cartilage develops from the 6th pharyngeal arch
Arytenoid cartilage
What aortic arches develop from pharyngeal arches
3rd - internal carotid artery
4th - aortic arch and brachiocephalic
6th - left and right pulmonary arteries
What does the 1st pharyngeal pouch give rise to
Tympanic cavity and Eustachian tube
What does the 2nd pharyngeal pouch give rise to
Palatine tonsils
What does the 3rd pharyngeal pouch give rise to
Ventral - thymus
Dorsal - inferior parathyroid gland
What does the 4th pharyngeal pouch give rise to
Dorsal - superior parathyroid gland
What happens to the pharyngeal clefts during development
1st cleft remains and forms the external auditory meatus
The 2nd pharyngeal arch obliterates all of the other clefts (obliterates the cervical sinus)
What happens if the cervical sinus isn’t obliterated
Branchial fistulae or cysts occur on the anterior border of the sternocleidomastoid
