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Questions and Answers
During tongue development, if the lateral lingual swellings failed to properly overgrow the tuberculum impar, what would be the most likely consequence?
During tongue development, if the lateral lingual swellings failed to properly overgrow the tuberculum impar, what would be the most likely consequence?
- Malformation of the epiglottis and laryngeal orifice.
- Absence of the anterior two-thirds of the tongue.
- A significantly reduced or absent body of the tongue. (correct)
- Impaired sensory innervation via the mandibular division of the trigeminal nerve.
A patient presents with a selective loss of taste sensation in the anterior two-thirds of their tongue, but retains general sensation. Which nerve is most likely affected?
A patient presents with a selective loss of taste sensation in the anterior two-thirds of their tongue, but retains general sensation. Which nerve is most likely affected?
- Hypoglossal nerve.
- Glossopharyngeal nerve.
- Mandibular division of the trigeminal nerve.
- Chorda tympani branch of the facial nerve. (correct)
A newborn is diagnosed with ankyloglossia where the frenulum extends to the tip of the tongue. What developmental process has most likely been disrupted?
A newborn is diagnosed with ankyloglossia where the frenulum extends to the tip of the tongue. What developmental process has most likely been disrupted?
- The proper cell degeneration to free the tongue from the floor of the mouth. (correct)
- The fusion of the lateral lingual swellings.
- The migration of myoblasts from occipital somites.
- The sensory innervation of the tongue by the glossopharyngeal nerve.
If a developing embryo experienced disruption to the fourth pharyngeal arch, which of the following structures related to tongue development would be most directly affected?
If a developing embryo experienced disruption to the fourth pharyngeal arch, which of the following structures related to tongue development would be most directly affected?
A patient has damage to the hypoglossal nerve. Which specific function of the tongue would be most affected?
A patient has damage to the hypoglossal nerve. Which specific function of the tongue would be most affected?
During tongue development, what would be the consequence if the second pharyngeal arch failed to contribute to the formation of the copula?
During tongue development, what would be the consequence if the second pharyngeal arch failed to contribute to the formation of the copula?
If the occipital somites failed to properly migrate during tongue development, which of the following would most likely occur?
If the occipital somites failed to properly migrate during tongue development, which of the following would most likely occur?
A developing embryo experiences abnormal development of the fourth pharyngeal arch. Which of the following sensory innervation deficits would most likely result from this abnormality?
A developing embryo experiences abnormal development of the fourth pharyngeal arch. Which of the following sensory innervation deficits would most likely result from this abnormality?
During a prenatal examination, it is noted that the lateral lingual swellings are significantly smaller than expected. Which of the following is the most likely consequence of this developmental anomaly?
During a prenatal examination, it is noted that the lateral lingual swellings are significantly smaller than expected. Which of the following is the most likely consequence of this developmental anomaly?
If cell degeneration during tongue development were incomplete, leaving excessive tissue connecting the tongue to the floor of the mouth, what condition would likely result?
If cell degeneration during tongue development were incomplete, leaving excessive tissue connecting the tongue to the floor of the mouth, what condition would likely result?
Flashcards
Lateral Lingual Swellings
Lateral Lingual Swellings
Forms the anterior two-thirds (body) of the tongue, originating from the first pharyngeal arch.
Terminal Sulcus
Terminal Sulcus
Separates the body of the tongue from the posterior third (root).
Third Pharyngeal Arch
Third Pharyngeal Arch
Grows over tissue of the second pharyngeal arch and provides sensory innervation to the root of the tongue.
Ankyloglossia (Tongue-Tie)
Ankyloglossia (Tongue-Tie)
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Hypoglossal Nerve
Hypoglossal Nerve
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Tuberculum Impar
Tuberculum Impar
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Copula (Hypobranchial eminence)
Copula (Hypobranchial eminence)
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Third Median Swelling
Third Median Swelling
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Trigeminal Nerve
Trigeminal Nerve
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Study Notes
- The tongue develops around 4 weeks in the embryo.
- It initially appears as two lateral lingual swellings and one medial swelling, the tuberculum impar.
- These three swellings originate from the first pharyngeal arch.
- The copula, or hypobranchial eminence, comes from the mesoderm of the second, third, and part of the fourth pharyngeal arches.
- The development of the epiglottis is marked by a third median swelling formed by the posterior part of the fourth arch.
- The laryngeal orifice sits directly behind this swelling, flanked by the arytenoid swellings.
- As the lateral lingual swellings grow, they merge and overgrow the tuberculum impar to form the anterior two-thirds (body) of the tongue.
- The mandibular division of the trigeminal nerve provides sensory innervation to the body of the tongue, as its mucosa originates from the first pharyngeal arch.
- The body and the posterior third of the tongue are separated by the V-shaped terminal sulcus.
- The posterior part, or root, of the tongue originates from the second, third, and parts of the fourth pharyngeal arches.
- Sensory innervation to the root of the tongue is supplied by the glossopharyngeal nerve, indicating that tissue of the third arch overgrows that of the second.
- The epiglottis and the extreme posterior part of the tongue are innervated by the superior laryngeal nerve, reflecting their development from the fourth arch.
- Most tongue muscles are derived from myoblasts originating in occipital somites, though some differentiate in situ.
- The hypoglossal nerve innervates tongue musculature.
- The body is supplied by the trigeminal nerve, the nerve of the first arch.
- The root is supplied by the glossopharyngeal and vagus nerves, the nerves of the third and fourth arches, respectively.
- Special sensory innervation (taste): the chorda tympani branch of the facial nerve serves the anterior two-thirds, and the glossopharyngeal nerve serves the posterior third.
Clinical Correlates
- Ankyloglossia (tongue-tie) occurs when the tongue isn't freed from the floor of the mouth.
- Normally, extensive cell degeneration occurs, and the frenulum is the only tissue that anchors the tongue.
- In ankyloglossia, the frenulum extends to the tip of the tongue.
- In the most common form of ankyloglossia, the frenulum extends to the tip of the tongue.
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