Cardioinhibitory parasympathetic preganglionic fibres reaching the cardiac plexus via the vagus originate predominantly from which medullary nucleus, rather than the dorsal motor nucleus of the vagus?
- A Inferior salivatory nucleus
- B Nucleus of the solitary tract
- C Nucleus ambiguus ✓
- D Spinal accessory nucleus
Correct answer: C. Nucleus ambiguus
Explanation
In humans the cardioinhibitory preganglionic neurons projecting to the cardiac ganglia lie mainly in the nucleus ambiguus, while the dorsal motor nucleus of the vagus contributes more to gastrointestinal and other visceral output. The nucleus of the solitary tract is a sensory relay receiving baroreceptor and chemoreceptor input, not a source of vagal motor fibres. The inferior salivatory nucleus supplies the parotid via the glossopharyngeal nerve.
Reference: Ganong's Review of Medical Physiology, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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