Podcast
Questions and Answers
Which set of processes is required for proper palate development?
Which set of processes is required for proper palate development?
- Fusion of the mandibular processes with the hyoid arch.
- Fusion of the primary and secondary palates with the frontonasal prominence.
- Fusion of the nasomedial process at the midline, fusion of the primary and secondary palates, and fusion of maxillary processes at the palatal raphe. (correct)
- Fusion of the frontonasal prominence with the maxillary processes.
The frontonasal prominence primarily gives rise to structures of the mandible.
The frontonasal prominence primarily gives rise to structures of the mandible.
False (B)
What developmental defect results from the failure of fusion between the nasomedial and maxillary processes?
What developmental defect results from the failure of fusion between the nasomedial and maxillary processes?
Cleft lip
Pharyngeal arches are ______ in nature, while pharyngeal pouches are ______ in nature.
Pharyngeal arches are ______ in nature, while pharyngeal pouches are ______ in nature.
Match the following cranial nerves with the corresponding pharyngeal arch.
Match the following cranial nerves with the corresponding pharyngeal arch.
The middle ear is primarily derived from which structures?
The middle ear is primarily derived from which structures?
Somatosensory innervation of the posterior 1/3 of the tongue is mainly supplied by CN VII (Facial nerve).
Somatosensory innervation of the posterior 1/3 of the tongue is mainly supplied by CN VII (Facial nerve).
What structure extends from the foramen cecum to the superficial pharynx before it atrophies?
What structure extends from the foramen cecum to the superficial pharynx before it atrophies?
The tympanic membrane is a combination of first pharyngeal groove ______, ______, and first pharyngeal pouch ______.
The tympanic membrane is a combination of first pharyngeal groove ______, ______, and first pharyngeal pouch ______.
Match the following eye structures with their germ layer origin:
Match the following eye structures with their germ layer origin:
Which of the following structures is NOT derived from the first pharyngeal arch?
Which of the following structures is NOT derived from the first pharyngeal arch?
The primary palate is formed by the fusion of palatal shelves.
The primary palate is formed by the fusion of palatal shelves.
What specific signal induces the overlying ectoderm to thicken and form the otic field during ear development?
What specific signal induces the overlying ectoderm to thicken and form the otic field during ear development?
The invaginated otic placode is known as the ______, which pinches off to form the ______.
The invaginated otic placode is known as the ______, which pinches off to form the ______.
A failure in the fusion of the choroidal fissure results in:
A failure in the fusion of the choroidal fissure results in:
Proper development of the palate is dependent on what?
Proper development of the palate is dependent on what?
What occurs if the nasomedial and maxillary processes do not fully fuse?
What occurs if the nasomedial and maxillary processes do not fully fuse?
The forehead is primarily a derivative of which structures?
The forehead is primarily a derivative of which structures?
What process best describes unilateral cleft lip?
What process best describes unilateral cleft lip?
Where do the pharyngeal arches appear on an embryo?
Where do the pharyngeal arches appear on an embryo?
The fourth pharyngeal arch gives rise to the what?
The fourth pharyngeal arch gives rise to the what?
Somatosensory innervation of the anterior 2/3 of the tongue is supplied by what cranial nerve?
Somatosensory innervation of the anterior 2/3 of the tongue is supplied by what cranial nerve?
Taste sensation of the anterior 2/3 of the tongue is supplied by what cranial nerve?
Taste sensation of the anterior 2/3 of the tongue is supplied by what cranial nerve?
The internal, endodermal depressions between pharyngeal arches are known as what?
The internal, endodermal depressions between pharyngeal arches are known as what?
Pharyngeal arches refer to the external bumps on an embryo's throat, while the dimples between each arch are known as what?
Pharyngeal arches refer to the external bumps on an embryo's throat, while the dimples between each arch are known as what?
The first pharyngeal arch gives rise to all of the following, except:
The first pharyngeal arch gives rise to all of the following, except:
Pharyngeal and laryngeal muscles are a derivative of which pharyngeal arch(es)?
Pharyngeal and laryngeal muscles are a derivative of which pharyngeal arch(es)?
Which structure elongates into the eustachian (auditory) tube?
Which structure elongates into the eustachian (auditory) tube?
Pharyngeal arch structures include which of the following germ layers?
Pharyngeal arch structures include which of the following germ layers?
What is the cause of thyroid dysgenesis?
What is the cause of thyroid dysgenesis?
Why is the somatosensory sensation of the anterior 2/3 of the tongue supplied by CN V, but its taste innervation is supplied by CN VII?
Why is the somatosensory sensation of the anterior 2/3 of the tongue supplied by CN V, but its taste innervation is supplied by CN VII?
The first pharyngeal arch gives rise to which nerve?
The first pharyngeal arch gives rise to which nerve?
The second pharyngeal arch gives rise to which nerve?
The second pharyngeal arch gives rise to which nerve?
The third pharyngeal arch gives rise to what structure of the tongue?
The third pharyngeal arch gives rise to what structure of the tongue?
The ear canal is derived from what groove?
The ear canal is derived from what groove?
All motor innervation of the tongue is supplied by which nerve?
All motor innervation of the tongue is supplied by which nerve?
The tympanic membrane is a combination of which three structures?
The tympanic membrane is a combination of which three structures?
The incus and malleus are derivatives of the _____ , while the stapes is a derivative of the _____.
The incus and malleus are derivatives of the _____ , while the stapes is a derivative of the _____.
The hyoid, stylohyoid ligament, and muscles of facial expression are all derivatives of which pharyngeal arch(es)?
The hyoid, stylohyoid ligament, and muscles of facial expression are all derivatives of which pharyngeal arch(es)?
The thymus and parathyroid glands are most often derivatives of what?
The thymus and parathyroid glands are most often derivatives of what?
The thyroid is a derivative of which structure?
The thyroid is a derivative of which structure?
Which of the following is not a derivative of the first pharyngeal arch?
Which of the following is not a derivative of the first pharyngeal arch?
What structure lies between the nasolateral process and maxillary process?
What structure lies between the nasolateral process and maxillary process?
Failure of fusion between palatal shelves at the palatal raphe is known as what condition?
Failure of fusion between palatal shelves at the palatal raphe is known as what condition?
Dacryostenosis occurs as a result of abnormal development and obstruction of the what?
Dacryostenosis occurs as a result of abnormal development and obstruction of the what?
Proper closure of the bridge of the nose requires full fusion of which structures?
Proper closure of the bridge of the nose requires full fusion of which structures?
Proper development of the lips and upper palate require full fusion of the what processes?
Proper development of the lips and upper palate require full fusion of the what processes?
An open palate may have been due to what?
An open palate may have been due to what?
A wide distance between the eyes may be as a result of what?
A wide distance between the eyes may be as a result of what?
What structures fuse to form the primary palate?
What structures fuse to form the primary palate?
Palatal shelves formed by _____ fuse at the palatal raphe to form the secondary palate.
Palatal shelves formed by _____ fuse at the palatal raphe to form the secondary palate.
Failure of fusion between nasomedial and maxillary processes on both sides of the face is known as?
Failure of fusion between nasomedial and maxillary processes on both sides of the face is known as?
What structures are important for proper oral development? Which of the following does not contribute to the tympanic membrane?
What structures are important for proper oral development? Which of the following does not contribute to the tympanic membrane?
What structures contribute to the tympanic membrane?
What structures contribute to the tympanic membrane?
What signals the overlying ectoderm to thicken into the otic field?
What signals the overlying ectoderm to thicken into the otic field?
Hearing loss as a result of hair cell or CN VIII damage describes what?
Hearing loss as a result of hair cell or CN VIII damage describes what?
What is the middle ear primarily derived from?
What is the middle ear primarily derived from?
What does the otic field thicken into?
What does the otic field thicken into?
The statoacoustic ganglion gives rise to what?
The statoacoustic ganglion gives rise to what?
Which structure is the cochlea derived from?
Which structure is the cochlea derived from?
The _____ is external to the tympanic membrane and typically degenerates by week 28?
The _____ is external to the tympanic membrane and typically degenerates by week 28?
In inner ear development, the otocyst splits into what?
In inner ear development, the otocyst splits into what?
Neurons from what structure projects to hair cells in the semicircular canals?
Neurons from what structure projects to hair cells in the semicircular canals?
Which of the following is not a derivative of the mesoderm?
Which of the following is not a derivative of the mesoderm?
The otic pit pinches off from the overlying ectoderm, creating what structures?
The otic pit pinches off from the overlying ectoderm, creating what structures?
Which structures are derivatives of the otocyst?
Which structures are derivatives of the otocyst?
_____ Six merge to form the shape of the external pinna.
_____ Six merge to form the shape of the external pinna.
The invaginated otic placode is known as the what?
The invaginated otic placode is known as the what?
The pars superior gives rise to the what?
The pars superior gives rise to the what?
What best describes the formation of the 8th cranial nerve?
What best describes the formation of the 8th cranial nerve?
What is the a highly vascularized layer of eye tissue?
What is the a highly vascularized layer of eye tissue?
Eye development primarily occurs in which germ layer?
Eye development primarily occurs in which germ layer?
What is defined as bulges that laterally appear from the neural tube in the diencephalon area?
What is defined as bulges that laterally appear from the neural tube in the diencephalon area?
In fetal development, vascularization occurs from _____ to _____.
In fetal development, vascularization occurs from _____ to _____.
The pigment and neural layers of the retina are derivatives of which structure?
The pigment and neural layers of the retina are derivatives of which structure?
The cornea is composed of which layers?
The cornea is composed of which layers?
The outer layer of the optic vesicle will form which layer of the retina?
The outer layer of the optic vesicle will form which layer of the retina?
What causes a uveal coloboma?
What causes a uveal coloboma?
In the cornea, a signal from the corneal endothelium causes water to follow sodium out of what structure?
In the cornea, a signal from the corneal endothelium causes water to follow sodium out of what structure?
What supports visual transparency?
What supports visual transparency?
What results in rhegmatogenous retinal detachment?
What results in rhegmatogenous retinal detachment?
What is common of congenital cataract?
What is common of congenital cataract?
From what germ layer is the sclera?
From what germ layer is the sclera?
What structure in the cornea is formed when neural crest cells migrate between the lens and ectodermal matrix?
What structure in the cornea is formed when neural crest cells migrate between the lens and ectodermal matrix?
Once a lens placode invaginates it becomes a _____, which will bud off of overlying ectoderm to become a _____.
Once a lens placode invaginates it becomes a _____, which will bud off of overlying ectoderm to become a _____.
What is the function of the ciliary body?
What is the function of the ciliary body?
Retinopathy of prematurity may result in what?
Retinopathy of prematurity may result in what?
What artery initially supplies the lens vesicle?
What artery initially supplies the lens vesicle?
In fetal eye development, when do more blood vessels develop?
In fetal eye development, when do more blood vessels develop?
In the cornea, neural crest cells migrate between the ectoderm and corneal endothelium to form the _____.
In the cornea, neural crest cells migrate between the ectoderm and corneal endothelium to form the _____.
As optic grooves enlarge, they turn into what?
As optic grooves enlarge, they turn into what?
From what structures does the iris develop from?
From what structures does the iris develop from?
The inner layer will form which layer of the retina?
The inner layer will form which layer of the retina?
The posterior face of the lens gives rise to which of the following structures?
The posterior face of the lens gives rise to which of the following structures?
Which of the following structures is directly formed by the pharyngeal arches?
Which of the following structures is directly formed by the pharyngeal arches?
Which pharyngeal arch is associated with the recurrent laryngeal nerve?
Which pharyngeal arch is associated with the recurrent laryngeal nerve?
From what germ layer does the core of the pharyngeal arch derive?
From what germ layer does the core of the pharyngeal arch derive?
The first pharyngeal groove persists as which adult structure?
The first pharyngeal groove persists as which adult structure?
What condition results from the failure of the 2nd, 3rd, and 4th pharyngeal grooves to obliterate?
What condition results from the failure of the 2nd, 3rd, and 4th pharyngeal grooves to obliterate?
From which pharyngeal pouch does the thymus develop?
From which pharyngeal pouch does the thymus develop?
What adult structure(s) result(s) from the expansion of the first pharyngeal pouch?
What adult structure(s) result(s) from the expansion of the first pharyngeal pouch?
What structures are derived from the mesoderm of the pharyngeal arches?
What structures are derived from the mesoderm of the pharyngeal arches?
The anterior 2/3 of the tongue is formed from the proliferation of mesenchyme from which pharyngeal arch?
The anterior 2/3 of the tongue is formed from the proliferation of mesenchyme from which pharyngeal arch?
What is a common clinical manifestation of an ectopic thyroid?
What is a common clinical manifestation of an ectopic thyroid?
Which of the following nerves is associated with the 3rd pharyngeal arch?
Which of the following nerves is associated with the 3rd pharyngeal arch?
What is the embryological origin of the thyroid gland?
What is the embryological origin of the thyroid gland?
From which pharyngeal arch artery does the common carotid artery primarily originate?
From which pharyngeal arch artery does the common carotid artery primarily originate?
Which of the following muscles is innervated by the nerve associated with the first pharyngeal arch?
Which of the following muscles is innervated by the nerve associated with the first pharyngeal arch?
A thyroglossal duct cyst is most commonly found in what location?
A thyroglossal duct cyst is most commonly found in what location?
The muscles of facial expression are derived from which pharyngeal arch?
The muscles of facial expression are derived from which pharyngeal arch?
What is the term for the embryological remnant that may persist as the pyramidal lobe of the thyroid gland?
What is the term for the embryological remnant that may persist as the pyramidal lobe of the thyroid gland?
The definitive pharynx is formed from the contribution of which structure?
The definitive pharynx is formed from the contribution of which structure?
What tissues are created through the fusion of the ultimobranchial body with the thyroid gland?
What tissues are created through the fusion of the ultimobranchial body with the thyroid gland?
What is the origin of most of the tongue's musculature?
What is the origin of most of the tongue's musculature?
A patient presents with a small, asymptomatic opening along the anterior border of the sternocleidomastoid muscle. This is most likely caused by what?
A patient presents with a small, asymptomatic opening along the anterior border of the sternocleidomastoid muscle. This is most likely caused by what?
From which of the following does the submandibular duct form?
From which of the following does the submandibular duct form?
Which of the following does not arise from the 4th and 6th pharyngeal arches?
Which of the following does not arise from the 4th and 6th pharyngeal arches?
Which arch is thought to be rudimentary or transient in development?
Which arch is thought to be rudimentary or transient in development?
What occurs during week 6 of development?
What occurs during week 6 of development?
During tongue development, what structure disappears as a result of being overgrown?
During tongue development, what structure disappears as a result of being overgrown?
Branchial is derived from the Greek word for what structure?
Branchial is derived from the Greek word for what structure?
Which arch is primarily involved in the development of the hyoid bone?
Which arch is primarily involved in the development of the hyoid bone?
Which CN innervates the muscles derived from the fourth and sixth pharyngeal arches, contributing to the formation of the larynx?
Which CN innervates the muscles derived from the fourth and sixth pharyngeal arches, contributing to the formation of the larynx?
Which of the following is a derivative of the first pharyngeal membrane?
Which of the following is a derivative of the first pharyngeal membrane?
Which structures are commonly associated with 1st arch syndrome, such as Mandibulofacial dystosis?
Which structures are commonly associated with 1st arch syndrome, such as Mandibulofacial dystosis?
In the context of pharyngeal arch development, what is the significance of neural crest cells?
In the context of pharyngeal arch development, what is the significance of neural crest cells?
What is the fate of the cervical sinus during embryonic development?
What is the fate of the cervical sinus during embryonic development?
A newborn presents with congenital heart defects, hypocalcemia, and thymic aplasia. Which developmental abnormality is most likely responsible for this presentation?
A newborn presents with congenital heart defects, hypocalcemia, and thymic aplasia. Which developmental abnormality is most likely responsible for this presentation?
What is the critical timeframe during embryogenesis when the pharyngeal arches begin to develop?
What is the critical timeframe during embryogenesis when the pharyngeal arches begin to develop?
Assuming normal development, what becomes of the aortic sac?
Assuming normal development, what becomes of the aortic sac?
A patient is diagnosed with Treacher Collins syndrome. What symptom is not seen?
A patient is diagnosed with Treacher Collins syndrome. What symptom is not seen?
A surgeon is preparing to resect a thyroglossal duct cyst from a child. Before the procedure, what is the most important consideration regarding the thyroid gland?
A surgeon is preparing to resect a thyroglossal duct cyst from a child. Before the procedure, what is the most important consideration regarding the thyroid gland?
In a developing embryo, which germ layer gives rise to the epithelial lining of the pharyngeal pouches?
In a developing embryo, which germ layer gives rise to the epithelial lining of the pharyngeal pouches?
What vascular anomaly arises from persistence of part of the 6th arch in development?
What vascular anomaly arises from persistence of part of the 6th arch in development?
What structures primarily comprise the facial prominences during embryonic development?
What structures primarily comprise the facial prominences during embryonic development?
During facial development, what marks the beginning of the 5th week?
During facial development, what marks the beginning of the 5th week?
What structures merge to form the intermaxillary segment?
What structures merge to form the intermaxillary segment?
What definitive structure does the intermaxillary segment give rise to?
What definitive structure does the intermaxillary segment give rise to?
Between what weeks of development does palatogenesis primarily occur?
Between what weeks of development does palatogenesis primarily occur?
The secondary palate, which forms the majority of the hard and soft palate, is derived from what specific structure?
The secondary palate, which forms the majority of the hard and soft palate, is derived from what specific structure?
What process is crucial for the palatine shelves to elevate from a vertical to a horizontal position during palate development?
What process is crucial for the palatine shelves to elevate from a vertical to a horizontal position during palate development?
Facial clefts result from which developmental deficiency?
Facial clefts result from which developmental deficiency?
An anterior cleft palate occurs when the palatine shelves fail to fuse with which structure?
An anterior cleft palate occurs when the palatine shelves fail to fuse with which structure?
From the perspective of nasal cavity development, at which week does communication between the nasal and oral cavities become established?
From the perspective of nasal cavity development, at which week does communication between the nasal and oral cavities become established?
What typically develops late in fetal life, contributing to the final development of the face?
What typically develops late in fetal life, contributing to the final development of the face?
During the final stages of facial development in the fetal period, what change occurs regarding the proportion and position of facial components?
During the final stages of facial development in the fetal period, what change occurs regarding the proportion and position of facial components?
What is a potential feeding problem associated with oral-facial clefts?
What is a potential feeding problem associated with oral-facial clefts?
In development of the face, at what point is the nasal placode apparent?
In development of the face, at what point is the nasal placode apparent?
What is the first step in treating an infant that has a cleft lip?
What is the first step in treating an infant that has a cleft lip?
A child with an anterior cleft palate would have difficulty with which process?
A child with an anterior cleft palate would have difficulty with which process?
A child is born without an opening to drain tears through the nasolacrimal duct? What structure is not functioning?
A child is born without an opening to drain tears through the nasolacrimal duct? What structure is not functioning?
The frontal part of the frontonasal prominence becomes what structure?
The frontal part of the frontonasal prominence becomes what structure?
When maxillary prominences merge medially toward each other, facial structure(s) develop?
When maxillary prominences merge medially toward each other, facial structure(s) develop?
During which week of development does the solid epithelial cord separate from the ectoderm and sink into the underlying mesenchyme during formation of the nasolacrimal duct?
During which week of development does the solid epithelial cord separate from the ectoderm and sink into the underlying mesenchyme during formation of the nasolacrimal duct?
The merging of the medial nasal and maxillary prominences results in the continuity of which structures?
The merging of the medial nasal and maxillary prominences results in the continuity of which structures?
What is one potential cause for malformation related to oblique facial clefts?
What is one potential cause for malformation related to oblique facial clefts?
What dental problem can result from a cleft palate?
What dental problem can result from a cleft palate?
In the development of the face, what is the direct consequence of the joining of maxillary processes and the mandibular arch moving medially?
In the development of the face, what is the direct consequence of the joining of maxillary processes and the mandibular arch moving medially?
During what time period does the forehead bulge forward as the brain enlarges?
During what time period does the forehead bulge forward as the brain enlarges?
What structure is shown?
What structure is shown?
Which statement best describes the development of the upper lip?
Which statement best describes the development of the upper lip?
A pregnant woman is concerned about cleft lip because she has taken a medication that inhibits cell migration. What tissue type is most likely affected?
A pregnant woman is concerned about cleft lip because she has taken a medication that inhibits cell migration. What tissue type is most likely affected?
As the face develops, the external acoustic meatus ascends to the side of the head during which weeks of development?
As the face develops, the external acoustic meatus ascends to the side of the head during which weeks of development?
If there is a defect to the tongue, what is not properly formed?
If there is a defect to the tongue, what is not properly formed?
Anterior cleft palates are distinguished by their failure to fuse with the incisive foramen and are primarily associated with malformation of the ______.
Anterior cleft palates are distinguished by their failure to fuse with the incisive foramen and are primarily associated with malformation of the ______.
A woman has a child with atresia of the nasolacrimal duct, and is partially corrected. What structure must the tear drop into to be fully corrected?
A woman has a child with atresia of the nasolacrimal duct, and is partially corrected. What structure must the tear drop into to be fully corrected?
What key event takes place during the 6th week of nasal cavity development?
What key event takes place during the 6th week of nasal cavity development?
What is the most likely course of treatment for a baby who's milk comes out of the nose when breast feeding?
What is the most likely course of treatment for a baby who's milk comes out of the nose when breast feeding?
A researcher is studying fetal development and observes that a particular embryo is failing to form a complete nasolacrimal duct. Further investigation reveals that the solid epithelial cord, which usually canalizes to create the duct, remains solid. Which cellular process is most likely impaired?
A researcher is studying fetal development and observes that a particular embryo is failing to form a complete nasolacrimal duct. Further investigation reveals that the solid epithelial cord, which usually canalizes to create the duct, remains solid. Which cellular process is most likely impaired?
What embryological structure gives rise to the tympanic cavity?
What embryological structure gives rise to the tympanic cavity?
From what structure is the endolymphatic duct and sac derived?
From what structure is the endolymphatic duct and sac derived?
The malleus is derived from which pharyngeal arch?
The malleus is derived from which pharyngeal arch?
What structures are derived from the ventral saccular portion of the otic vesicle?
What structures are derived from the ventral saccular portion of the otic vesicle?
When does ossification of the auditory ossicles typically complete?
When does ossification of the auditory ossicles typically complete?
The auricle or pinna develops from tissue derived from what?
The auricle or pinna develops from tissue derived from what?
What is the origin of the intermediate layer of the tympanic membrane?
What is the origin of the intermediate layer of the tympanic membrane?
The inner ear reaches adult size and shape by what point in gestation?
The inner ear reaches adult size and shape by what point in gestation?
What stimulates the mesenchyme to differentiate into a cartilaginous otic capsule?
What stimulates the mesenchyme to differentiate into a cartilaginous otic capsule?
When does the meatal plug typically dissolve in the developing external auditory meatus?
When does the meatal plug typically dissolve in the developing external auditory meatus?
What part of the ear continues it's growth through puberty?
What part of the ear continues it's growth through puberty?
The ossicles are embedded in loose mesenchyme from which structure?
The ossicles are embedded in loose mesenchyme from which structure?
Which of the following defects is considered the most common congenital ear defect associated with hearing loss in children?
Which of the following defects is considered the most common congenital ear defect associated with hearing loss in children?
The formation of the tympanic cavity has it's beginnings in which month of gestation?
The formation of the tympanic cavity has it's beginnings in which month of gestation?
What structure participates in formation of the definitive eardrum?
What structure participates in formation of the definitive eardrum?
What is the result of the meatal plug persisting until birth?
What is the result of the meatal plug persisting until birth?
What is the function of HOXA2 in auricle development?
What is the function of HOXA2 in auricle development?
What part of the ear is derived from the first pharyngeal groove?
What part of the ear is derived from the first pharyngeal groove?
Which of the following is least likely to result in congenital ear malformations?
Which of the following is least likely to result in congenital ear malformations?
What is the role of retinoic acid and transforming growth factor β1 in the development of the cochlear duct?
What is the role of retinoic acid and transforming growth factor β1 in the development of the cochlear duct?
What is the first step in the development of the otic vesicle?
What is the first step in the development of the otic vesicle?
The spiral ganglion contains ganglion cells for which nerve?
The spiral ganglion contains ganglion cells for which nerve?
What is the significance of the surface ectoderm in the development of the Otic Placodes? (select the best answer)
What is the significance of the surface ectoderm in the development of the Otic Placodes? (select the best answer)
True or False: Functional hearing occurs by approximately gestation week 20.
True or False: Functional hearing occurs by approximately gestation week 20.
Flashcards
Proper palate development depends on?
Proper palate development depends on?
Fusion of the nasomedial process at the midline, fusion of the primary and secondary palates, fusion of maxillary processes at the palatal raphe
What causes cleft lip?
What causes cleft lip?
Failure of fusion between the nasomedial and maxillary processes.
What causes unilateral cleft lip?
What causes unilateral cleft lip?
Failure of fusion between the nasomedial and maxillary processes on one side of the face
Where do the pharyngeal arches appear?
Where do the pharyngeal arches appear?
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What does the fourth pharyngeal arch give rise to?
What does the fourth pharyngeal arch give rise to?
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Pharyngeal arches vs. pouches nature?
Pharyngeal arches vs. pouches nature?
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Anterior 2/3 tongue somatosensory innervation?
Anterior 2/3 tongue somatosensory innervation?
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Posterior 1/3 tongue innervation?
Posterior 1/3 tongue innervation?
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Internal depressions between pharyngeal arches?
Internal depressions between pharyngeal arches?
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What contributes to the tympanic membrane?
What contributes to the tympanic membrane?
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Signals to thicken otic field?
Signals to thicken otic field?
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What are derivatives of the otocyst?
What are derivatives of the otocyst?
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What merges to form the external pinna?
What merges to form the external pinna?
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The invaginated otic placode is known as the?
The invaginated otic placode is known as the?
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Between nasolateral and maxillary process?
Between nasolateral and maxillary process?
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Frontonasal Prominence
Frontonasal Prominence
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Pharyngeal Pouches
Pharyngeal Pouches
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CN VII
CN VII
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Pharyngeal pouches
Pharyngeal pouches
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Pharyngeal grooves
Pharyngeal grooves
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1st Pharyngeal pouch
1st Pharyngeal pouch
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Thyroglossal duct
Thyroglossal duct
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Thyroid dysgenesis
Thyroid dysgenesis
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Pharyngeal arch composition
Pharyngeal arch composition
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First pharyngeal arch
First pharyngeal arch
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Second pharyngeal arch
Second pharyngeal arch
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1st pharyngeal pouch
1st pharyngeal pouch
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Optic grooves
Optic grooves
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Lens Pit and Lens Vesicle
Lens Pit and Lens Vesicle
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Ciliary Body
Ciliary Body
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Pharyngeal Apparatus
Pharyngeal Apparatus
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Pharyngeal Arches
Pharyngeal Arches
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Pharyngeal Arch Components
Pharyngeal Arch Components
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Pharyngeal Membranes
Pharyngeal Membranes
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Branchial
Branchial
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Trigeminal Nerve (CN V)
Trigeminal Nerve (CN V)
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Facial Nerve (CN VII)
Facial Nerve (CN VII)
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Glossopharyngeal Nerve (CN IX)
Glossopharyngeal Nerve (CN IX)
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Vagus Nerve (CN X)
Vagus Nerve (CN X)
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Pharyngeal (Branchial) Cyst
Pharyngeal (Branchial) Cyst
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Pharyngeal (Branchial) Fistula
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Pharyngeal (Branchial) Sinuses
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1st Aortic Arch Derivatives
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2nd Aortic Arch Derivatives
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3rd Aortic Arch Derivatives
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Left 4th Aortic Arch Derivatives
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Right 4th Aortic Arch Derivatives
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Left 6th Aortic Arch Derivatives
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Muscles of Mastication
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3rd and 4th pharyngeal pouches syndrome
3rd and 4th pharyngeal pouches syndrome
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Typical pharyngeal arch
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Pharyngeal Arches
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Thyroid gland
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Development of Tongue
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Abnormal thyroid conditions
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Development of Salivary Gland
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Parotid formation
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Sublingual glad formation
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Facial Prominences Time Frame
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Frontonasal Prominence Components
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Facial Prominences Composition
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Nasal Placodes Appearance
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Nasal Prominences Role
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Lower jaw and lip formation.
Lower jaw and lip formation.
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Naso-optic Groove Description
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Nasolacrimal Groove Timing
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Nasolacrimal Duct Development
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Intermaxillary Segment Formation
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Merged Prominences Result
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Median Palatine Process Outcome
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Ear Canal Origin
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Ear Tubercle Movement
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Palate Development
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Palate Origin
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Palatogenesis Timing
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Primary Palate Forms
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Secondary Palate Forms
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Palatine Shelves Position
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Palatine Shelves Fate
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Cleft Palate Cause
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Anterior Cleft Palate Location
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Posterior Cleft Palate Location
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Oblique Facial Cleft Cause
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Oral-Facial Clefts Correction
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Cleft Lip Repair Timing
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Cleft Palate Repair Timing
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Cleft Palate Aid
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Oronasal Membrane Origin
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Nasal Cavity Communication Timing
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Final Face Development Timing
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Final Face Development Character
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What is the ear?
What is the ear?
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Otic Placode Formation
Otic Placode Formation
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What is an otic pit?
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What is the otic vesicle (otocyst)?
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What is the Dorsal utricular portion?
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What is the Ventral saccular portion?
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Cartilaginous otic capsule
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Perilymphatic space
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What is the spiral ganglion?
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What are the maculae?
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Cristae ampullares
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Organ of Corti
Organ of Corti
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What is the tympanic cavity?
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What is the tubotympanic recess?
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Proximal part of pouch
Proximal part of pouch
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When does the tympanic cavity form?
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Malleus and incus origin
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What is the stapes’ origin?
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Ossification of ossicles
Ossification of ossicles
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What is the eardrum?
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External Auditory Meatus Development
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Tympanic Membrane Composition
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What is the auricle (pinna)?
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External Auditory Meatus Abnormalities
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What is Microtia?
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Study Notes
Development of the Ear
- The ear functions as the organ of balance and hearing.
Inner Ear Development
- Inductive influences from the notochord and paraxial mesoderm stimulate the surface ectoderm to form the otic placodes.
- Fibroblast growth factors initiate specification of the otic-progenitors.
- Further inner ear development involves Pa2GH4, transcription factors Fox 1/3, Pax2/8, the Wnt, and Notch pathways.
- Each otic placode soon invaginates and sinks, forming an otic pit.
- The edges of the otic pit come together and fuse to form an otic vesicle.
- The otic vesicle loses its connection with the surface ectoderm.
- Successive stages in development transforms the otic vesicle into the membranous labyrinth from the 5th to 8th weeks of development.
- A diverticulum grows from the vesicle and elongates to form the endolymphatic duct and sac.
- The dorsal utricular portion forms the small endolymphatic ducts, utricles, and semicircular ducts.
- The ventral saccular portion gives rise to the saccule and cochlear duct.
- Inductive influences from the otic vesicle stimulate the mesenchyme to differentiate into a cartilaginous otic capsule.
- The cartilaginous otic capsule ossifies to form the bony labyrinth.
- Retinoic acid and transforming growth factor β1 have a role in cochlear duct and perilymphatic space development.
- Vacuoles appear in the cartilaginous otic capsule as the membranous labyrinth enlarges, forming the perilymphatic space
- The membranous labyrinth is now suspended in the perilymphatic space.
- Around the cochlear duct, the scala tympani and scala vestibuli are formed.
- The internal ear reaches its adult size and shape by the middle of the fetal period (20–22 weeks).
- Functional hearing occurs by approximately week 26.
- Ganglion cells of the 8th cranial nerve cells migrate into the cochlea, forming the spiral ganglion.
- Nerve processes extend and terminate on hair cells of the spiral organ, and the cells remain bipolar neurons.
- Specialized sensory receptors are located in six regions of the membranous labyrinth.
- The 2 maculae sense the position of the head and linear movement through macula of saccule (vertical) and macule of utricle (horizontal)
- The 3 cristae ampullaris are located in the ampulla of the semicircular ducts and are sensitive to angular acceleration.
- The spiral organ of Corti is the sound receptor.
Middle Ear Development
- The tympanic cavity, derived from the first pharyngeal pouch, originates in the endoderm.
- The distal part of the pouch, the tubotympanic recess, widens and gives rise to the primitive tympanic cavity.
- The proximal part remains narrow and forms the auditory (Eustachian) tube, through which the tympanic cavity communicates with the nasopharynx.
- Formation of the tympanic cavity starts in the 3rd month and finishes by the 8th month.
- The malleus and incus develop from cartilage in the first pharyngeal arch.
- The stapes develop from the second pharyngeal arch.
- Ossification of the auditory ossicles starts at 16 weeks and finishes by 26 weeks.
- Expansion of the tympanic cavity gives rise to the mastoid antrum, in the temporal bone.
- At birth, the antrum is almost adult size and the middle ear continues to grow through puberty.
- The handle of the malleus makes contact with the eardrum.
- The stapes establish contact with the membrane in the oval window.
External Ear Development
- Structures include the external auditory meatus, tympanic membrane, and auricle (pinna).
- The external auditory meatus develops from the first pharyngeal arch as an invagination of the ectoderm.
- The tympanic cavity separates from the tympanic membrane (eardrum).
- During the 3rd month, the meatal plug forms and dissolves in the 7th month, while the floor of the meatus participates in the definitive eardrum formation.
- Occasionally, the meatal plug persists until birth, resulting in congenital deafness.
- The eardrum or tympanic membrane is made of: 1) surface ectodermal epithelium at the bottom of the external auditory meatus, 2) endodermal epithelial lining of the tympanic cavity
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- an intermediate layer of connective tissue (fibrous stratum).
- The auricle (pinna) develops from proliferation of tissues derived from the neural crest at the dorsal ends of the 1st and 2nd pharyngeal arches.
- The process involves molecular pathways regulating HOXA2 expression, which appears critical for auricle development and reaches adult form by 22 weeks.
- Mutations in genes involved in these pathways cause many external ear malformations, often in combination with abnormalities in structures, such as the face, skull, and heart.
Ear Malformations
- Microtia (small auricle) results from suppressed auricular hillocks development.
- Absence of the external acoustic meatus results from inward expansion failure of the 1st pharyngeal groove, or meatal plug failing to disappear. Absence of the external acoustic meatus results in Atresia or blockage results from failure of meatal plug to canalize.
- Additional associations include first arch syndrome and autosomal dominant inheritance.
- Congenital deafness affects 1 in 1000 infants with severe hearing loss
- Congenital deafness can result from maldevelopment of the sound conducting apparatus (external middle ear) or the neurosensory structures of the inner ear.
- Enlargement of the vestibular aqueduct and endolymphatic duct is the most common congenital ear defect in children with hearing loss, presenting bilaterally with autosomal recessive condition.
- Rubella infection in the sensitive period affects the formation of the spiral organ (organ of Corti) and also causes deafness.
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