Gracile nucleus

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Brain: Gracile nucleus
Section of the medulla oblongata at the level of the decussation of the pyramids. Gracile nucleus is #8.
Dissection of brain-stem. Dorsal view. ("nucleus gracilis" is labeled on left, second from the bottom.)
Latin	nucleus gracilis
Gray's	subject #187 774
Part of
Components
Artery
Vein
BrainInfo/UW	hier-763
MeSH	[1]

Located in the medulla oblongata, the gracile nucleus is one of the dorsal column nuclei that participates in the sensation of fine touch and proprioception. It contains second-order neurons of the dorsal column-medial lemniscus system which receive inputs from sensory neurons of the dorsal root ganglia and send axons that synapse in the thalamus.

The neurons contained within the nucleus form a visible bump called the gracile tubercle on the posterior side of the closed medulla at the floor of the fourth ventricle.

The gracile nucleus and fasciculus carry epicritic, kinesthetic, and conscious proprioceptive information from the lower part of the body (below the level of T6 in the spinal cord). The counterpart to the gracile nucleus and fasciculus is the cuneate nucleus and fasciculus, which carries the same type of information, but from the upper body (above T6, excepting the face and ear - the information from the face and ear is carried by the primary sensory trigeminal nucleus).

[edit] Additional images

Decussation of pyramids.	Dissection of brain-stem. Lateral view.	Deep dissection of brain-stem. Lateral view.	Superior terminations of the posterior fasciculi of the medulla spinalis.
Section of the medulla oblongata at about the middle of the olive.	Diagram showing the course of the arcuate fibers.	The formatio reticularis of the medulla oblongata, shown by a transverse section passing through the middle of the olive.	Scheme showing the course of the fibers of the lemniscus; medial lemniscus in blue, lateral in red.
Gray714.png Transverse section passing through the sensory decussation.	Deep dissection of cortex and brain-stem.	The sensory tract.

[edit] External links

• BrainMaps at UCDavis gracile%20nucleus

v·d·e Brain: rhombencephalon (hindbrain)
Metencephalon/ pons	{| class="navbox collapsible nowraplinks" style="margin:auto; background:white;background:white;"
[[[:Template:Fullurl:Template:]] v]·[[[:Template:Fullurl:Template talk:]] d]·[[[:Template:Fullurl:Template:]] e]
Dorsal/ (tegmentum)	surface: Locus ceruleus Trigeminal lemniscus (Dorsal trigeminal tract, Ventral trigeminal tract) cranial nuclei: GSA: Principal V/Spinal V - VIII-c (Dorsal, Anterior)/VIII-v (Lateral, Superior, Medial, Inferior) - SVE: Motor V - VII - GSE: VI - GVE: VII: Superior salivary nucleus MLF, III, IV and VI (vestibulo-oculomotor fibers, medial vestibulospinal tract) sensory/ascending: Trapezoid body/VIII - Superior olivary nucleus Inferior cerebellar peduncle (Vestibulocerebellar tract) motor/descending: Apneustic center • Pneumotaxic center (Medial parabrachial nucleus) - Lateral parabrachial nucleus
Ventral/ (base)	Middle cerebellar peduncles (Pontocerebellar fibers) - Pontine nuclei motor/descending: Corticospinal tract - Corticobulbar tract - Corticopontine fibers
Raphe/reticular	Reticular formation (Caudal, Oral, Tegmental, Paramedian) • Raphe nuclei (Median)

|- style="white-space:nowrap;background:#ddddff;text-align:right;background-color: LightYellow" ! Myelencephalon/
medulla | colspan="1" style="text-align:left;width:100%;font-size:95%;background:#f7f7f7;" | {| class="navbox collapsible nowraplinks" style="margin:auto; background:white;background:white;" |- style="text-align:center;width:100%;"

!colspan="2" |

|- |- style="white-space:nowrap;background:#ddddff;text-align:right;padding-left:0em;padding-right:0em;background-color: LightYellow"

!

| colspan="1" style="text-align:left;width:100%;font-size:95%;" | surface: Posterior median sulcus - Postero-lateral sulcus - Area postrema

cranial nuclei: GVA: VII,IX,X: Solitary/tract • SVA: Gustatory nucleus • GSE: XII  • GVE: IX,X,XI: Ambiguus • SVE: X: Dorsal • IX: Inferior salivatory nucleus - MLF, III, IV and VI

sensory/ascending: Gracile nucleus • Cuneate nucleus (Accessory cuneate nucleus) • Sensory decussation  • Medial lemniscus

motor/descending: Dorsal respiratory group
|- style="white-space:nowrap;background:#ddddff;text-align:right;padding-left:0em;padding-right:0em;background-color: LightYellow"

!

| colspan="1" style="text-align:left;width:100%;font-size:95%;background:#f7f7f7;" | motor/descending: Ventral respiratory group - Pyramid (Motor decussation) - Inferior olivary nucleus (Olivocerebellar tract, Rubro-olivary tract)
surface: Anterior median fissure - Antero-lateral sulcus - Arcuate nucleus of medulla - Olivary body
|- style="white-space:nowrap;background:#ddddff;text-align:right;padding-left:0em;padding-right:0em;background-color: LightYellow"

!

| colspan="1" style="text-align:left;width:100%;font-size:95%;" | Reticular formation (Gigantocellular, Parvocellular, Ventral, Lateral, Paramedian) • Raphe nuclei (Obscurus, Magnus, Pallidus) |} |}

This page uses content from the English-language version of Wikipedia. The original article was at Gracile nucleus. The list of authors can be seen in the page history. As with Psychology Wiki, the text of Wikipedia is available under the GNU Free Documentation License.