NEET PG Medical – 2019 – Question – 12
What is the nerve supply of Submandibular gland:
a) Auriculotemporal nerve
b) Lingual nerve
c) Glossopharyngeal nerve
d) Inferior alveolar nerve
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Correct Answer – B
Answer B. Lingual Nerve
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- The submandibular glands receive autonomic innervation through parasympathetic and sympathetic fibres, which directly and indirectly regulate salivary secretions respectively.
Parasympathetic
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- Parasympathetic innervation originates from the superior salivatory nucleus through pre-synaptic fibres, which travel via the chorda tympani branch of the facial nerve (CN VII).
- The chorda tympani then unifies with the lingual branch of the mandibular nerve (CNVIII) before synapsing at the submandibular ganglion and suspending it by two nerve filaments.
- Post-ganglionic innervation consists of secretomotor fibres which directly induce the gland to produce secretions, and vasodilator fibres which accompany arteries to increase blood supply to the gland. Increased parasympathetic drive promotes saliva secretion.
Sympathetic
- Sympathetic innervation originates from the superior cervical ganglion, where post-synaptic vasoconstrictive fibres travel as a plexus on the internal and external carotid arteries, facial artery and finally the submental arteries to enter each gland. Increased sympathetic drive reduces glandular blood flow through vasoconstriction and decreases the volume of salivary secretions, resulting in a more mucus and enzyme-rich saliva.
