Podcast
Questions and Answers
What is the primary source of the facial skeleton?
What is the primary source of the facial skeleton?
Which structure does the frontonasal process contribute to?
Which structure does the frontonasal process contribute to?
What occurs during the elimination of furrows in facial development?
What occurs during the elimination of furrows in facial development?
The medial nasal processes contribute to which of the following structures?
The medial nasal processes contribute to which of the following structures?
Signup and view all the answers
What is required for the fusion of processes in facial development?
What is required for the fusion of processes in facial development?
Signup and view all the answers
Which processes are involved in the formation of the secondary palate?
Which processes are involved in the formation of the secondary palate?
Signup and view all the answers
What results from incomplete proliferation of mesenchyme during facial development?
What results from incomplete proliferation of mesenchyme during facial development?
Signup and view all the answers
What structure marks the boundary between the stomodeum and the primitive pharynx?
What structure marks the boundary between the stomodeum and the primitive pharynx?
Signup and view all the answers
Which structure is formed by the first pharyngeal membrane?
Which structure is formed by the first pharyngeal membrane?
Signup and view all the answers
What does pouch 3 give rise to?
What does pouch 3 give rise to?
Signup and view all the answers
From which pharyngeal arch does the anterior two-thirds of the tongue primarily develop?
From which pharyngeal arch does the anterior two-thirds of the tongue primarily develop?
Signup and view all the answers
Which cranial nerve primarily innervates the taste buds in the anterior two-thirds of the tongue?
Which cranial nerve primarily innervates the taste buds in the anterior two-thirds of the tongue?
Signup and view all the answers
Where does the thyroid diverticulum develop?
Where does the thyroid diverticulum develop?
Signup and view all the answers
Which nerve is responsible for motor innervation of the tongue muscles?
Which nerve is responsible for motor innervation of the tongue muscles?
Signup and view all the answers
What primarily contributes to the connective tissue and vasculature of the tongue?
What primarily contributes to the connective tissue and vasculature of the tongue?
Signup and view all the answers
What developmental structure covers cleft 4 to form the cervical sinus?
What developmental structure covers cleft 4 to form the cervical sinus?
Signup and view all the answers
Which components are included in the pharyngeal arches?
Which components are included in the pharyngeal arches?
Signup and view all the answers
What is the fate of the neural crest cells in relation to the pharyngeal arches?
What is the fate of the neural crest cells in relation to the pharyngeal arches?
Signup and view all the answers
In which weeks do the pharyngeal arches typically form?
In which weeks do the pharyngeal arches typically form?
Signup and view all the answers
Which cranial nerve innervates the second pharyngeal arch?
Which cranial nerve innervates the second pharyngeal arch?
Signup and view all the answers
What is the inner lining of the pharyngeal arches composed of?
What is the inner lining of the pharyngeal arches composed of?
Signup and view all the answers
Which pharyngeal arch is not paired with a specific cranial nerve?
Which pharyngeal arch is not paired with a specific cranial nerve?
Signup and view all the answers
Which mesodermal component primarily gives rise to the muscles associated with the pharyngeal arches?
Which mesodermal component primarily gives rise to the muscles associated with the pharyngeal arches?
Signup and view all the answers
What is the role of endoderm in epithelial-mesenchymal interactions during development of the pharyngeal apparatus?
What is the role of endoderm in epithelial-mesenchymal interactions during development of the pharyngeal apparatus?
Signup and view all the answers
Which muscle is NOT derived from the paraxial mesoderm?
Which muscle is NOT derived from the paraxial mesoderm?
Signup and view all the answers
What is the sensory innervation for the muscles of the larynx?
What is the sensory innervation for the muscles of the larynx?
Signup and view all the answers
Which structure develops from the first pharyngeal pouch?
Which structure develops from the first pharyngeal pouch?
Signup and view all the answers
Which cranial nerve innervates the stylopharyngeus muscle derived from the third pharyngeal arch?
Which cranial nerve innervates the stylopharyngeus muscle derived from the third pharyngeal arch?
Signup and view all the answers
What does the fourth pharyngeal pouch give rise to?
What does the fourth pharyngeal pouch give rise to?
Signup and view all the answers
Which cells are derived from the ultimopharyngeal body formed by the fourth pouch?
Which cells are derived from the ultimopharyngeal body formed by the fourth pouch?
Signup and view all the answers
Which structure is formed from the second pharyngeal pouch?
Which structure is formed from the second pharyngeal pouch?
Signup and view all the answers
Which of the following connections is formed by the first pharyngeal membrane?
Which of the following connections is formed by the first pharyngeal membrane?
Signup and view all the answers
What forms the philtrum of the lip during the development of the primary palate?
What forms the philtrum of the lip during the development of the primary palate?
Signup and view all the answers
During which weeks of development does the secondary palate form?
During which weeks of development does the secondary palate form?
Signup and view all the answers
What anatomical landmark marks the midline division between the primary and secondary palate?
What anatomical landmark marks the midline division between the primary and secondary palate?
Signup and view all the answers
What is the primary cause of cleft lip?
What is the primary cause of cleft lip?
Signup and view all the answers
What indicates the completion of palate fusion during development?
What indicates the completion of palate fusion during development?
Signup and view all the answers
What type of cleft results from a lack of fusion of palatine shelves?
What type of cleft results from a lack of fusion of palatine shelves?
Signup and view all the answers
Which component of the primary palate contributes to the formation of the premaxilla of the upper jaw?
Which component of the primary palate contributes to the formation of the premaxilla of the upper jaw?
Signup and view all the answers
What is a common misconception about the causes of cleft palate?
What is a common misconception about the causes of cleft palate?
Signup and view all the answers
What forms from the maxillary process during development?
What forms from the maxillary process during development?
Signup and view all the answers
Which cranial nerve is responsible for the sensory innervation of the face in pharyngeal arch 1?
Which cranial nerve is responsible for the sensory innervation of the face in pharyngeal arch 1?
Signup and view all the answers
Which muscle is NOT derived from the first pharyngeal arch?
Which muscle is NOT derived from the first pharyngeal arch?
Signup and view all the answers
What are the skeletal components formed from the second pharyngeal arch?
What are the skeletal components formed from the second pharyngeal arch?
Signup and view all the answers
Which of the following muscles is associated with cranial nerve VII?
Which of the following muscles is associated with cranial nerve VII?
Signup and view all the answers
Micrognathia, or mandibular hypoplasia, is associated with which developmental aspect?
Micrognathia, or mandibular hypoplasia, is associated with which developmental aspect?
Signup and view all the answers
Which of the following muscles is NOT derived from the first pharyngeal arch?
Which of the following muscles is NOT derived from the first pharyngeal arch?
Signup and view all the answers
Study Notes
Pharyngeal Apparatus
- Includes pharyngeal arches (branchial arches)
- Lined by ectoderm on the outside, mesoderm core
- Neural crest cells form skeletal components and connective tissue
- Lateral plate mesoderm forms cartilage in arches 4 and 6. Also includes nerves, arteries, and cartilage
- Lined by endoderm on the inside
- Contains pharyngeal clefts (grooves) and pouches (endoderm)
- Also includes pharyngeal membranes
- Crucial for thyroid and tongue development (except arch 1)
Epithelial-Mesenchymal Interactions
- Endoderm signals overlying ectoderm.
- Ectoderm signals underlying neural crest.
Characteristics of Pharyngeal Arches
- Form in weeks 4-5
- Five arches (numbered 1-6)
- Outer lining: ectoderm
- Inner lining: endoderm (except arch 1)
- Core: paraxial mesoderm, neural crest, and lateral plate mesoderm
- Each arch contains an artery, cartilage, and a cranial nerve.
Neural Crest Cell Migration
- P1: Midbrain and rhombomeres 1-2
- P2: Rhombomere 4
- P3: Rhombomeres 6-7
Skeletal Components of Pharyngeal Arches
- Some bones form directly from cartilage.
- Other bones form from intramembranous ossification of neural crest cells.
Muscle and Nerve Supply
- Arches 1-3 from unsegmented paraxial mesoderm
- Arches 4 and 6 from somites 1-5
- Tongue muscles migrate from somites 1-5
- Arch 1: CN V (trigeminal)
- Arch 2: CN VII (facial)
- Arch 3: CN IX (glossopharyngeal)
- Arch 4: CN X (vagus)
- Arch 6: CN XII (hypoglossal)
First Pharyngeal Arch (Mandibular)
- Maxillary cartilage (regresses)
- Maxilla, zygomatic, palatine, lacrimal, vomer, squamous part of temporal bone (develop from neural crest cells)
- Mandibular process
- Meckel's cartilage (forms malleus and incus)
Second Pharyngeal Arch (Hyoid Arch)
- Reichert cartilage
- Stapes
- Styloid process of the temporal bone
- Stylohyoid ligament
- Lesser horn and upper body of hyoid bone
Nerves and Muscles
- Cranial nerve VII (facial) innervates muscles of facial expression (buccinator, auricularis, frontalis, platysma, orbicularis oris and oculi)
- Cranial nerve VII (facial) innervates some taste buds
- CN V, IX, and X innervate taste buds
Third Pharyngeal Arch
- Skeletal component: the lower body and greater horn of the hyoid bone
- Mesoderm forms the stylopharyngeus muscle.
- Innervated by glossopharyngeal nerve IX
Fourth and Sixth Pharyngeal Arches
- Paraxial mesoderm forms muscles of the larynx and pharynx
- Cartilage forms the larynx (cricothyroid, constrictors of pharynx, levator veli palatini, intrinsic muscles of the larynx, and skeletal muscles of the upper esophagus)
- Sensory innervation: CN X (vagus)
- Most tongue muscles innervated by CN XII, except palatoglossus (CN X)
Pharyngeal Arches Derivatives
- Arch 1: muscles of mastication, CN V, Meckel's cartilage, malleus, incus
- Arch 2: facial muscles, CN VII, upper portion of hyoid, Reichert cartilage, stapes, styloid process of temporal bone
- Arch 3: stylopharyngeus muscle, CN IX, lower part of hyoid bone, and greater horn of hyoid
- Arches 4&6: pharyngeal muscles, CN X & XII, thyroid and cricoid cartilage
Pharyngeal Pouches
- First pouch: middle ear and auditory tube
- Second pouch: palatine tonsils
- Third pouch: inferior parathyroid glands and thymus
- Fourth pouch: superior parathyroid glands and C-cells of thyroid.
Thyroid Gland
- Thyroid diverticulum develops from the midline of the second pharyngeal arch at the foramen cecum
- Descends to its final position over the superior tracheal rings.
Tongue Development
- Anterior two-thirds formed from pharyngeal arch 1
- Root formed from arch 3 (some from arch 4)
- The terminal sulcus marks the division between ectoderm and endoderm
- Connective tissue and vasculature come from neural crest cells
- Muscles of the tongue mostly migrate from occipital somites.
Sensory Innervation of Tongue
- Anterior two-thirds: CN V (first arch)
- Posterior one-third: CN IX (third arch)
- Some from CN X (fourth arch)
Nasal, Nasal Cavity, and Oral Cavity
- Nasal placodes invaginate to form nasal pits
- Nasal septum (intermaxillary segment) grows down and attaches to the palate
- Maxillary process grow medially
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on the pharyngeal apparatus and the crucial epithelial-mesenchymal interactions during development. This quiz covers the formation and characteristics of pharyngeal arches, neural crest cell migration, and their significance in the development of structures such as the thyroid and tongue.
