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Neurons of the SN are notably functionally arranged roughly length-wise along the nucleus: gustatory neurons are situated rostrally (with afferents from the anterior part of the tongue and roof of oral cavity rostral-most, and those from the larynx and epiglottis more caudally placed); gastrointestinal, cardiovascular, respiratory neurons are situated more caudally.
A cranial nerve nucleus is a collection of neurons (gray matter) in the brain stem that is associated with one or more of the cranial nerves. Axons carrying information to and from the cranial nerves form a synapse first at these nuclei. Lesions occurring at these nuclei can lead to effects resembling those seen by the severing of nerve(s) they ...
The hypoglossal nucleus is a cranial nerve nucleus, found within the medulla.Being a motor nucleus, it is close to the midline. In the open medulla, it is visible as what is known as the hypoglossal trigone, a raised area (medial to the vagal trigone) protruding slightly into the fourth ventricle.
Upon decussation (crossing over) from one side of the medulla to the other, also known as the sensory decussation, they are then called the medial lemniscus. The internal arcuate fibers are part of the second-order neurons of the posterior column-medial lemniscus system , and are important for relaying the sensation of fine touch and ...
Medulla: Located in the jugular foramen. Receives taste from the posterior 1/3 of the tongue, provides secretomotor innervation to the parotid gland, and provides motor innervation to the stylopharyngeus. Some sensation is also relayed to the brain from the palatine tonsils. This nerve is involved together with the vagus nerve in the gag reflex. X
Ten of the twelve pairs of cranial nerves either target or are sourced from the brainstem nuclei. [14]: 725 The nuclei of the oculomotor nerve (III) and trochlear nerve (IV) are located in the midbrain. The nuclei of the trigeminal nerve (V), abducens nerve (VI), facial nerve (VII) and vestibulocochlear nerve (VIII) are located in the pons.
The medulla and pons also contain numerous small nuclei with a wide variety of sensory, motor, and regulatory functions. In the peripheral nervous system (PNS), a cluster of cell bodies of neurons (homologous to a CNS nucleus) is called a ganglion. The fascicles of nerve fibers in the PNS (homologous to CNS tracts) are called nerves.
The ventral portion of the medulla oblongata contains the medullary pyramids. These two ridge-like structures travel along the length of the medulla oblongata and are bordered medially by the anterior median fissure. They each have an anterolateral sulcus along their lateral borders, where the hypoglossal nerve emerges from.