Question

What are two examples of visceral sensory receptors in the ANS. What stimuli do they measure and what responses by the CNS do they elicit.

Answer 1

Answer :

Visceral afferent neurons are sensory neurons that conduct impulses initiated in receptors in smooth muscle & cardiac muscle. Visceral afferent neurons are unipolar neurons that enter the spinal cord through the dorsal root & their cell bodies are located in the dorsal root ganglia.

The example of visceral sensory receptors are

1)The geniculate ganglion :

The geniculate ganglion contains special sensory neuronal cell bodies for taste, from fibers coming up from the tongue through the chorda tympani and from fibers coming up from the roof of the palate through the greater petrosal nerve.Sensory and parasympathetic inputs are carried into the geniculate ganglion via the nervus intermedius. Motor fibers are carried via the facial nerve proper. The greater petrosal nerve, which carries preganglionic parasympathetic fibers, emerges from the anterior aspect of the ganglion.

The motor fibers of the facial nerve proper and parasympathetic fibers to the submandibular and pterygopalatine ganglia do not synapse in the geniculate ganglion. The afferent fibers carrying pain, temperature, and touch from the posterior auricular nerve, as well as those carrying special sensory (taste) fibers from the tongue (via the chorda tympani), do not synapse in the geniculate ganglion. Instead, the cells of the geniculate ganglion relay the signal to the appropriate brainstem nucleus, much like the Dorsal root ganglion neurons relay signal to nuclei in the spinal cord.

The geniculate ganglion is one of several ganglia of the head and neck. Like the others, it is a bilaterally distributed structure, with each side of the face having a geniculate ganglion.

2)petrosal:

The greater petrosal nerve carries parasympathetic preganglionic fibers from the facial nerve. The greater petrosal nerve joins with the deep petrosal nerve (postganglionic sympathetic axons from the internal carotid plexus) continues and continues as the nerve of the pterygoid canal and ultimately synapses with the pterygopalatine ganglion whose parasympathetic postganglionic fibers synapse with the lacrimal gland and the mucosal glands lining the nasal cavity and palate.

3)nodose ganglion :

The inferior ganglion of the vagus nerve, (nodose ganglion) is a sensory ganglion of the peripheral nervous system. It is located within the jugular foramen where the vagus nerve exits the skull. It is larger than and below the superior ganglion of the vagus nerve.

These receptors appended respectively to cranial nerves VII, IX and X.

These sensory receptors monitor the levels of carbon dioxide, oxygen and sugar in the blood, arterial pressure .