Term
| Where in the brain receives spinal cord info? |
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Definition
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Term
| Where in the brain does the spinal cord receive info from? |
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Definition
| Cortex, thalamus, cerebellum, and brain stem |
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Term
| What are the "grooves" in the spinal cord? |
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Definition
| Dorsal and ventral median sulci, as well as two dorsal intermediate sulci. |
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Term
| What are the spinal nerves? (There are 31) |
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Definition
8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal.
C1 to C7 exit above, while T1 to the end exit below |
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Term
| Dentate ligament attaches what to what? |
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Definition
| pia to arachnoid and dura. |
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Term
| Where does the spinal cord develope from? |
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Definition
| The caudal aspect of the neural tube. Motor neurons (ventral root) may derive from here. |
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Term
| DRG cells originate from? |
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Definition
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Term
| Cauda equina starts (conus medullaris ends) where? |
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Definition
| L1 and L2. So a lumbar puncture can be done at L3/L4 |
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Term
| Trend in white/gray matter in spinal cord? |
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Definition
| White:gray ratio is higher in rostral locations. |
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Term
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Definition
10 zones:
1. Marginal Zone
2. Substantia gelatinosa
3-6. Nucleus Proprius
7. Lateral Horn and Clark's nucleus or nucleus dorsalis
8. interneurons
9. Motor neurons
10. Propriospinal zone
Note 9 is really two islands in the 7th and 8th zones |
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Term
| Zones isolated to levels of spinal cord: |
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Definition
Phrenic Nucleus (C3-C5)
Clarke's nuclus/Nucleus dorsalis (T1-L3) This is the relay nucleus for the posterior spinocerebellar tract
Lateral Horn/Intermediolateral cell column (T1-L3) - Preganglionic sympathetic neurons |
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Term
White matter is divided into?
Gray matter is divided into? |
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Definition
White matter: Dorsal, Lateral, and Ventral faniculi
Gray matter: Dorsal zone, intermediate zone, and ventral horn. |
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Term
Ascending white matter tracts?
Descending? |
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Definition
Dorsal columns, spinothalamic tract, and spinocerebellar tract.
Descending - corticospinal |
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Term
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Definition
Above T6 there are two regions:
Fasciculus gracilis (legs and lower body exists at all levels) and
Fasciculus cuneatus which deals with the upper body only exists above T6. |
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Term
| Describe the stretch, patellar, or monosynaptic reflex |
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Definition
| A postural reflex where the patellar tendon is tapped. This stretches the quadriceps femoris muscle. It activates stretch receptors, which activates sensory DRG neurons, which activates lower motor neurons, and the muscle contracts extending the leg at the knee |
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Term
| Describe the flexor withdrawel reflex |
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Definition
| A protective reflex (withdrawel due to painful stimulis). Multisynaptic in nature. Leg, for example, activates the hamstring and inhibits the quadricep. |
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Term
| What are the Major Ascending Tracts? |
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Definition
Posterior Column - Medial Lemniscus Pathway
Spinothalamic Tract
Spinocerebellar Tract |
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Term
| Posterior Column - Medial Lemniscus Pathway |
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Definition
Mediates concious proprioception, vibration, light touch, and fine tactile discrimination. Decussation: Brainstem.
Peripheral receptor -> DRG -> Fasciculus Gracilis/Cuneatus, Synapses in nucelus gracilis/cuneatus, decussates via internal arcuate fibers in brainstem, forms medial lemniscus, synapses in thalamus, ascends through internal capsule, and synapses in postcentral gyrus. |
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Term
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Definition
Mediates pain, temperature, crude touch sensation. Decussates in cord near point of entry.
Peripheral receptor -> DRG -> Sensory neuron -> Synapses in substantia gelatinosa -> Ducussates in ventral white commisure ->Ascends as spinothalamic tract -> synapses in thalamus -> Ascends in internal capsule -> Synapsewes in poscentral gyrus. |
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Term
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Definition
Mediates unconcious proprioception. Posterior spinocerebellar tract is mainly from ipsalateral leg. This synapses in Clarke's nucleus (so seen only above L2).
From arm: Fasciculus cuneatus -> Lateral cuneate nucleus in brainstem.
Anterior spinocerebellar tract: Via nucleus proprius, crosses in cord and again in cerebellum. Thus effects are ipsalateral as well. |
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Term
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Definition
| Spinoolivary, spinotectal, and spinoreticular |
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Term
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Definition
Corticospinal
As well: rebrospinal, reticulospinal, tectospinal, vestibulospinal |
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Term
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Definition
Ducussates about 85% in brainstem, 15% in spinal cord.
Of the brainstem decussating fibers: occurs in pyramids and descends as the lateral corticospinal tract.
Of the 15% which stay ipsalateral in brainstem: Descend as medial corticospinal tract and decussate in the ventral white commisure.
Targets are interneurons and lower motor neurons of the ventral horn.
Lesion: Produces upper motor neuron signs - spastic paralysis, hyperactive reflexes (Babinski sign). Lower motor neurons show flacid paralysis and atrophy. |
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Term
What is the filum terminale?
Where is it? |
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Definition
| Strand of fibrous tissue below the caudal end of the spinal cord (conus medullaris). It is an extension of the pial covering of the conus medullaris. |
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Term
| Where does the dural sac of the spinal cord end? |
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Definition
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Term
| Where does the dural sac of the spinal cord end? |
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Definition
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Term
| The posterior horn of spinal gray matter contains what? |
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Definition
| Mainly interneurons which are wholly contained in the spinal cord and projection neurons (somatic and visceral sensory) whose axons collect into long ascending sensory pathways. |
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Term
| What parts of the posterior horn are contained in all spinal cord segments? |
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Definition
| The body of the posterior horn and the substantia gelatinosa. |
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Term
| The substantia gelatinosa carries mainly what type of fibers? |
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Definition
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Term
| What does the anterior horn of the spinal cord contain? |
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Definition
| Motor neurons. Cell bodies of large motor neurons - alpha motor neurons that alone are ultimately responsible for voluntary/involuntary movement. |
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Term
| What are responsible for the efferent limbs of reflex reactions? |
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Definition
| Lower motor neurons (alpha motor neurons) in the anterior horn. |
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Term
What do gamma motor neurons innervate?
What is their alternate name? |
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Definition
| Intrafusal muscle fibers of muscle spindles. Also referred to as fusimotor. |
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Term
| What are two important columns of nuclei in the anterior horn of the spinal cord? |
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Definition
| Spinal accessory nucleus (caudal medulla to C5) and the phrenic nucleus (C3-C5) |
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Term
| What does the intermediate gray matter contain? |
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Definition
| Spinal preganglionic autonomic neurons. At some levels, Clarke's nucleus (nucleus dorsalis). Sympathetic autonomics are T1 to L3 in the intermediolateral cell column. |
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Term
| What is the function of Clarke's Nucleus? |
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Definition
| Important for the transmission of information to the cerebellum. May also play a role in forwarding proprioceptive information from the leg to the thalamus. |
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Term
Lamina I
Lamina II
Lamina III-VI
Lamina VII
Lamina IX
Lamina X |
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Definition
Lamina I - Marginal Zone - Some spinothalamic tract cells
Lamina II - Substantia gelatinosa - Modulate transmission of pain and temp
Lamina III-VI - Body of posterior horn- Sensory Processing
Lamina VII - Clarke's - Posterior spinocerebellar tract cells (T1-L2), Interomediolateral Cell Column - Preganglionic sympathetic neurons (T1-L3), and Sacral Parasympathetic Nucleus - Preganglionic parasympathetic neurons (S2-S4)
Lamina IX - Accessory Nucleus (Medulla-C5) - Motor Neurons -> Sternocleidomastoid+Trap, Phrenic Nucleus (C3-C5)
Lamina X - Zone of gray matter surrounding the central canal. |
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Term
| Why is the stretch reflex special? |
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Definition
| It involves only two neurons (no interneurons). Monosynaptic/Myotatic. Ia afferent from muscle spindle synapses with spinal cord directly on an alpha motor neuron. |
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Term
| The fasciculis cuneatus occurs above what spinal level? |
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Definition
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