L-10-pharyngeal Flashcards
Pharyngeal Apparatus
Q: What are the components of the pharyngeal apparatus?
A: Pharyngeal arches (mesoderm), pharyngeal pouches (endoderm), pharyngeal clefts (ectoderm), pharyngeal membranes.
Pharyngeal Arches
Q: How many pharyngeal arches are present in human development?
A: There are six initially, but the fifth arch disappears, leaving five visible arches.
Q: What are the components of a pharyngeal arch?
A: Core of mesoderm, cartilaginous bar, pharyngeal arch artery, nerve, and muscle.
Derivatives of Pharyngeal Arches
Q: What are the skeletal and muscle derivatives of the 1st pharyngeal arch?
A:
• Bones: Mandible, maxilla, part of the temporal bone, malleus, incus.
• Muscles: Muscles of mastication, mylohyoid, anterior belly of digastric.
• Nerve: Mandibular branch of the trigeminal nerve (CN V).
Q: What are the skeletal and muscle derivatives of the 2nd pharyngeal arch?
A:
• Bones: Stapes, styloid process, stylohyoid ligament, upper hyoid bone.
• Muscles: Muscles of facial expression, posterior belly of digastric, stylohyoid, stapedius.
• Nerve: Facial nerve (CN VII).
Q: What are the derivatives of the 3rd pharyngeal arch?
A:
• Bone: Lower part of the hyoid, greater horn of the hyoid.
• Muscle: Stylopharyngeus.
• Nerve: Glossopharyngeal nerve (CN IX).
Q: What are the derivatives of the 4th pharyngeal arch?
A:
• Bones/Cartilage: Thyroid cartilage, cricoid cartilage, arytenoid cartilage.
• Muscles: Cricothyroid, pharyngeal constrictors.
• Nerve: Vagus nerve (CN X).
Pharyngeal Clefts & Pouches
Q: What does the 1st pharyngeal cleft develop into?
A: The external auditory meatus.
Q: What does the 1st pharyngeal pouch develop into?
A: Middle ear cavity and auditory tube.
Q: What does the 3rd pharyngeal pouch develop into?
A: Inferior parathyroid glands and thymus.
Q: What does the 4th pharyngeal pouch develop into?
A: Superior parathyroid glands.
Clinical Conditions
Q: What is Pierre Robin syndrome?
A: A first pharyngeal arch disorder characterized by micrognathia (small jaw), glossoptosis (tongue displacement), and cleft palate.
Q: What causes a branchial cyst?
A: Failure of obliteration of the second pharyngeal cleft, leading to a painless mass in the anterior triangle of the neck.
