Questions and Answers
What structure begins to develop around the 4th week of gestation and is crucial for tongue formation?
Which cranial nerve provides sensory innervation to the anterior 2/3 of the tongue?
The posterior 3rd of the tongue develops from which structure derived from the mesoderm?
Which cranial nerve is responsible for the sensory innervation of the posterior part of the tongue?
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What is the primary origin of the connective tissue and vasculature of the tongue?
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What is the condition characterized by the congenital absence of the tongue?
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Which of the following structures is primarily responsible for the formation of the anterior part of the tongue?
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At which gestational week do the lateral lingual swellings begin to grow?
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Which cranial nerve is primarily responsible for innervating the muscle components of the tongue?
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Which part of the tongue is influenced by the 4th pharyngeal arch during its development?
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What condition is characterized by an abnormally small tongue leading to limited muscular movement?
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The failure of lateral swellings to merge during development results in which condition?
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Ankyloglossia is commonly referred to as what?
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Macroglossia is often associated with which congenital defect syndrome?
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Which of the following describes the failure in cellular degeneration leading to tongue anchorage to the floor of the mouth?
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Which of the following is TRUE about microglossia?
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Study Notes
Development of the Tongue
- The tongue is a muscular organ located in the oral cavity, vital for taste and initial swallowing.
- Development begins around the 4th week of gestation with a medial swelling from the 1st pharyngeal arch called the tuberculum impar.
- By the 5th week, two lateral lingual swellings from the same arch grow, merge, and overlap the tuberculum impar, forming the anterior two-thirds of the tongue.
- The anterior tongue receives sensory innervation from the mandibular branch of the trigeminal nerve (V cranial nerve).
Formation of the Posterior Tongue
- The posterior third of the tongue arises from a median swelling known as the hypobranchial eminence (or copula) originating from the 2nd, 3rd, and 4th pharyngeal arches.
- This area gets sensory innervation from the glossopharyngeal nerve (IX cranial nerve).
- The posterior-most tongue region, associated with the epiglottis, develops from the 4th pharyngeal arch and is innervated by the superior laryngeal nerve.
Musculature of the Tongue
- The connective tissue and blood vessels of the tongue derive from cranial neural crest cells (CNCC).
- Myoblasts responsible for tongue muscles originate from occipital somites, migrating into the tongue primordium.
- Muscle cells receive innervation primarily from the hypoglossal nerve (XII cranial nerve), except for the palatoglossus muscle.
Tongue Anomalies
- Aglossia: Rare congenital absence of the tongue, typically due to severe maldevelopment of the first pharyngeal arches.
- Microglossia (Hypoglossia): An uncommon condition characterized by an abnormally small tongue, leading to restricted muscular movement.
- Macroglossia: Tongue enlargement often associated with congenital syndromes like Down syndrome (trisomy 21).
- Ankyloglossia: Condition resulting from insufficient cellular degeneration, causing an abnormally short lingual frenulum and restricted tongue movement; can range from mild to severe fusion.
- Cleft Tongue (Bifid Tongue): Occurs when lateral swellings fail to merge, leading to a split tongue; can be either partial or complete.
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Description
This quiz explores the intricate process of tongue development from an embryological perspective. Starting around the fourth week of gestation, the tongue's formation significantly impacts the oral cavity. Test your knowledge on the developmental stages and anomalies associated with the tongue.
