C19-Spinal cord

Dorsal root ganglia contain the cell bodies of motor neurons.

Each dorsal root is typically divided into 10-12 rootlets.

The lateral section of the dorsal root conveys fine touch and vibration sensations.

Aδ and C fibers enter the dorsal horn at the level of the Lissauer dorsolateral tract.

Second-order neurons in lamina I receive input from Aβ fibers.

The green neuron in the substantia gelatinosa is primarily involved in the direct transmission of pain signals.

The medial section of the dorsal root feeds into the spinothalamic tract.

The ascending branch of Aβ fibers within the dorsal funiculus terminates in the cuneate and gracilis nuclei.

The spinocerebellar tract transmits conscious proprioceptive information to the cerebellum.

Mossy fibers of the cerebellum are directly connected to the axons of proprioceptive neurons.

The intermedio-lateral column contains preganglionic parasympathetic neurons primarily within the T1-L2 segments.

The intermedio-medial column primarily receives afferent input from the ventral roots related to motor reflexes.

Lamina VIII interneurons project exclusively ipsilaterally to laminae 7 and 9.

The phrenic nucleus, located in the C2-C5 ventromedial region, controls the muscles of the limbs.

The Onuf nucleus, situated in the S1-S2 ventrolateral region, innervates muscles for sphincters.

The accessory spinal nucleus, located in the C1-C5 lateral area, receives bilateral inputs from the corticospinal tract to control lateral neck muscles.

Rexed lamina X is exclusive to the posterior horn of the spinal cord.

The gray commissure is divided into an anterior and a posterior part by the central nucleus.

The intermediate zone of the spinal cord gray matter predominantly consists of Rexed laminae VI, VII, and IX.

The fasciculus proprius is predominantly found within the lateral columns of the white matter.

The vestibulospinal, reticulospinal, and tectospinal tracts are all ascending sensory pathways.

The reticulospinal tract originates from the superior colliculus.

Medial descending tracts connect with the ventromedial gray matter to control distal limb muscles.

The tectospinal tract has ipsilateral projections and is involved in posture.

Lateral corticospinal and rubrospinal tracts control distal muscles by targeting the dorsolateral grey matter of the ventral laminae.

Corticospinal projections are 60% contralateral and 40% ipsilateral, primarily targeting motor neurons in the spinal cord.

The rubrospinal tract projects ipsilaterally onto interneurons.

Aminergic tracts from the brainstem use only serotonin and noradrenaline as neurotransmitters in the spinal cord for modulation.

The raphe-spinal system uses noradrenaline as a neurotransmitter and the coeruleus-spinal tract uses serotonin.

Vegetative projections from the upper centers target the spinal cord preganglionic neurons.

The periaqueductal grey, once activated, will primarily activate the neurons which are insensitive to endorphins.

Neurons in the periaqueductal grey project to the locus coeruleus and the raphe nucleus, which project down to first order neurons.

Morphine and enkephalins act by randomly diffusing inside our body, targeting second order neurons.

Lamina I receives afferent fibers carrying only pain and temperature sensations.

The dorsomarginal nucleus, also known as Rexed lamina I, only contributes fibers for the lateral spinothalamic tract.

The substantia gelatinosa of Rolando is primarily composed of Golgi type I neurons.

The gelatinosa cells receive sensory input exclusively from the central fibers of unipolar neurons of the dorsal root ganglia.

In the Substantia Gelatinosa, inhibitory interneurons synapse on Lamina VI.

Efferent neurons from Lamina II project only to more cranial segments of the spinal cord.

Descending fibers from higher centers form only excitatory synapses with the gelatinosa cells.

Lamina I directly sends second order neurons to the lateral geniculate nucleus of the thalamus.

The reticular formation, specifically the locus coeruleus and raphe magnus, project down to affect enkephalinergic pain modulating neurons in Lamina I.

The unmyelinated axons of gelatinosa cells are sparsely branched.