Flashcards in Spinal Cord Anatomy Deck (45):
How does the brain receive conscious proprioceptive information?
Through the branches of the medial bundle of the DRG that ascends through dorsal part of white matter from spinal cord to brain.
How does the brain receive unconscious proprioceptive information.
Clarke's column/thoracic nucleus/nucleus dorsalis
Through the branches of the medial bundle of the DRG that travel to Clarke's column.
What is the difference between the relationship of the dura to bone in the brain vs spinal column?
The dura is tightly adherent to the inner surface of the bony plate in the cranium, but it is separate from the bony vertebrae in the SC.
Which sensory nuclei of the spinal gray ascend the entire length of the SC?
substantia gelatinosa, dorsal proper nucleus
What input does the substantia gelatinosa receive and from where? Where does it send the information?
pain/temp from dorsal root
sends information to dorsal proper nucleus
What is the function of the dorsal proper nucleus?
processes pain/temp info and sends it upstream
Where along the SC is Clarke's column located?
Where do the neurons of Clarke's column receive info?
collaterals in posterior part of white matter
What is the role of Clarke's column?
processes (unconscious) proprio information from lower limb to cerebellum
What regions of the spinal cord have a lateral horn?
What comes off the lateral horn? Where do they go?
Sympathetic, preganglionic neurons to sympathetic chain
What regions of the spinal cord have a sacral autonomic nucleus?
What comes off the sacral autonomic nucleus? Where do they go?
Parasympathetic preganglionic spinal outflow to lower end of intestinal tract (region of semicolon down)
The medial pool of LMNs in the ventral horn: location in spinal cord? what do they supply?
entire spinal cord; supplies axial musculature
The lateral pool of LMNs in the ventral horn: location in spinal cord? what do they supply?
cervical and lumbo-sacral swellings; supplies appendicular musculature
The LMNs at the top of the lateral pool supply flexors/extensors while those at the bottom of the lateral pool supply flexors/extensors
Dorsal proper nucleus
Lamina VII & VIII
Ventral horn alpha motor neurons
surrounds central canal
What is the medial bundle of the dorsal root?
large, myelinated Aalpha Abeta fibres, rapidly conducting, conscious proprioception and fine touch information to brain; some fibres into thoracic nucleus; convey sensory information of a conscious nature
Where are the cell bodies of origin for the axons that comprise the dorsal root?
pseudounipolar neurons int he DRG
What is the lateral bundle of the dorsal root?
smallers, lightly or unmyelinated Adelta and C fibres, slowly conducting
pain, crude touch, temp to substantia gelatinosa
incoming visceral information (axons coming in from splanchnic nerves through sympathetic ganglia)
Which is more rapidly conducted: proprioception or pain?
Where does the lateral horn sympathetic pregnaglionic neurons leave the spinal cord?
What is the path of the sympathetic preganglionic neurons once it leaves the spinal cord?
white ramus communicantes --> sympathetic chain --> up/down or synapse --> post synaptic neuron --> grey ramus communicantes --> spinal nerve --> sympathetic innervation of peripheral structures
continue through sympathetic ganglia --> splanchnic nerves --> peripheral ganglia --> post synaptic neurons --> viscera of thorax and abdomen
What types of structures require sympathetic innervation?
smooth muscles in walls of arteries, glands, sweat glands, pilar erector muscles
Parasympathetic preganglionic neurons exit via the ventral root in what levels of the spinal cord? Where are they distributed?
S2 to S4; postganglionic neurons embedded in walls of viscera
Why do cervical and portions of the lumbar and sacral segments not have GVEs?
There is no lateral horn (sympathetic outflow) or parasympathetic outflow (only seen in S2-S4)
What type of information is carried by the dorsal column-medial lemniscal system? Conscious or unconscious
CONSCIOUS proprioception, fine touch, vibration
Where does info related to conscious proprioception, fine touch, vibration cross?
Decussation of the medial lemniscus
What fibres of the dorsal column-medial lemniscal system cross? Where?
internal arcuate fibres - axons cross in decussation of the medial lemniscus
What type of information is carried by the spinocerebellar pathways? Conscious or unconscious?
Where do axons of the dorsal spinocerebellar tract cross?
Where do axons of the ventral spinocerebellar tract cross?
Cerebellar white matter
Where do axons of 2nd order neurons in dorsal horn of the lumbar cord cross before ascending in the ventral spinocerebellar tract?
Ventral white commissure
What type of information is carried by the anterolateral system - lateral spinothalamic tract?
pain, temperature, crude touch
Where does information carried by the anteriolateral system-lateral spinothalamic tract cross?
ventral white commissure
What is contained in the ventral root?
axons of alpha (LMNs) distributed to skeletal musculature for voluntary and reflex control of striated muscle
axons of autonomic preganglionic neurons in control of visceral muscles and glands (S&PS depending on SC level)
What are general somatic afferents (GSA)?
sensory fibres coming from somatic regions of body conveying general information
What are general visceral afferents (GVA)?
Visceral sensory input related to general sensation
What are general somatic efferents (GSE)?
voluntary and reflex control of somatic muscles (alpha motor neuron outflow)