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65 Cards in this Set
- Front
- Back
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What is rexed's laminae |
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What are the nuclei of the posterior (dorsal) horn of the grey matter. What type of nuclei are they |
-Substantia gelatinosa of rolandi (SGR) -Nucleus proprius -Clark's Dorsal Nucleus
These are sensory nuclei |
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Give the afferent, efferent and crossing of the SGR |
Afferent: pain and temp via central processes of dorsal root ganglion cells Efferent: axons cross opposite in white commissure and ascend in lateral column white matter Crossing: These do cross. Lateral spinothalamic tract |
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Give the afferent, efferent and crossing of the Nucleus proprius |
Afferent: light pressure and crude touch via central processes of dorsal root ganglion cells Efferent: axons cross opposite side in white commissure and ascend in anterior white matter Crossing: These do cross. Anterior spinothalamic tract |
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Give the afferent, efferent and crossing of Clark's dorsal nucleus |
Afferent: proprioception via collaterals from fibers in posterior column white matter Efferent: axons ascend without crossing in the lateral column of the same side Crossing: No crossing. Posterior spinocerebellar tract |
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What are the nuclei of the anterior horn |
Medial group: anteromedial and posteromedial Lateral group: anterolateral and posterolateral Central group (only in cervical) |
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Give the afferent and efferent of the Medial group |
Afferent: pyramidal, extra pyramidal, proprioceptive impulse from muscles, short associative tracts for reflex arc Efferent: innervate axial trunk muscles |
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Give the afferent and efferent of the lateral group |
Afferent: pyramidal, extra pyramidal, proprioceptive impulse from muscles, short associative tracts for reflex arc Efferent: innervate muscles of upper and lower limbs |
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Give the afferent and efferent of the central group |
Afferent: pyramidal, extra pyramidal, proprioceptive impulse from muscles, short associative tracts for reflex arc Efferent: runs in phrenic nerve to diaphragm, spinal accessory supplies trapezius and sternocleidomastoid |
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What are the nuclei of the lateral horn |
Sympathetic: Lateral horns T1-L2/L3 Parasympathetic: Lateral Horns S2-S4
(lateral horn is the blue dotted area from previous pictures) |
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Give the afferent and efferent of Sympathetic: Lateral horns T1-L2/L3 |
Afferent: descending autonomic fibers from higher centers in hypothalamus and higher centers in brain and brainstem Efferent:Axons leave cord in ventral roots of spinal nerves as preganglionic fibers to relay in corresponding ganglia of sympathetic chain |
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Give the afferent and efferent of Parasympathetic: Lateral Horns S2-S4 |
Afferent: descending autonomic fibers from higher centers in hypothalamus and higher centers in brain and brainstem Efferent:Axons leave cord in ventral roots of spinal nerves as preganglionic fibers to relay on terminal ganglia |
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Describe the lamination of the white matter in the anterolateral system |
Anterolateral system is arranged leg-trunk-arm-neck, in that order from superficial to deep explaining why lesions exerting sustained gradual pressure will cause loss of pain and temperature in sacral dermatomes before higher segments. |
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What do the Gracile fascicles (tract) and Cuneate fascicles (tract) of the posterior column contain |
Gracile: leg and lower trunk Cuneate: upper trunk, arm, neck, occiput |
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Describe the clinical significance of the layout of the posterior column |
Because the posterior column is ordered leg-lower trunk-upper trunk-arm-neck-occiput from medial to lateral that means the cervical dermatomes will be affected first and sacral one last with sustained external pressure |
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What are the Ascending and Descending Tracts of the posterior (dorsal) column |
Ascending: gracile and cuneate
Descending: none |
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What are the Ascending and Descending Tracts of the Anterior (ventral) column |
Ascending: anterior spinothalamic (aka anterolateral system)
Descending Tracts: Anterior corticospinal, tectospinal, vestibulospinal (medial vestibulospinal tract), reticulospinal (medullary and pontine reticulospinal) |
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What are the Ascending and Descending Tracts of the Lateral column |
Ascending: lateral spinothalamic (part of anterolateral system), Dorsal and ventral spinocerebellar,
Descending: lateral corticospinal, rubrospinal, It also says there is a lateral tectospinal but I don't see it. |
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Which tracts carry conscious sensations |
gracile cuneate lateral spinothalamic ventral spinothalamic |
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Describe the sensation carried, origin and termination of the gracile tract |
Sensation: proprioception and fine touch from LOWER 1/2 (gracile has an L in it) of body Origin: cells of dorsal root ganglion central process pass in dorsal root and ascend in the dorsal column Termination: gracile nucleus in closed medulla |
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Describe the sensation carried, origin and termination of the Cuneate tract |
Sensation: proprioception and fine touch from UPPER 1/2 (cuneate has a U in it) of body Origin: cells of dorsal root ganglion central process pass in dorsal root and ascend in the dorsal column Termination: cuneate nucleus in closed medulla |
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Describe the sensation carried, origin and termination of the lateral spinothalamic tract |
Sensation: pain and temp from contralateral side below the head Origin: axons of the SGR cross in front of the central canal Termination: posterolateral ventral nucleus of thalamus (PLVN) |
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Describe the sensation carried, origin and termination of the anterior spinothalamic tract |
Sensation: crude touch and light pressure from contralateral side below the head Origin: axons of the nucleus proprius cross Termination: PLVN of thalamus |
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Which tracts carry unconscious sensation |
dorsal (posterior) spinocerebellar Ventral (anterior) spinocerebellar Spinoolivary spinotectal |
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Describe the sensation carried, origin and termination of the dorsal (posterior) spinocerebellar tract |
Sensation: proprioception from trunk and lower limb to cerebellum Origin: Axons of Clark nucleus to the SAME side Termination: Ascend to cerebellum of the same side |
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Describe the sensation carried, origin and termination of the Ventral (anterior) spinocerebellar tract |
Sensation: proprioception from lower limb to cerebellum Origin: axons of cells at base of posterior horn cross to the opposite side Termination: ascend to the midbrain and then RECROSS to cerebellum of the SAME side |
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Describe the sensation carried, origin and termination of the olivary tract |
Sensation: proprioception to olivary nucleus of medulla Origin: axons of large cells at base of posterior horn cross to the opposite side Termination: inferior olivary nucleus to cerebellum via olivo cerebellar fibers |
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Describe the sensation carried, origin and termination of the spinotectal tract |
Sensation: pain, temp, touch to tectum of midbrain (carry spino-visual reflexes) Origin: axons of cells at posterior horn cross to the opposite side Termination: superior colliculus of the tectum of the midbrain. |
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What are the two types of conscious sensations |
exteroceptive: from skin (pain, temp, touch) enteroceptive: from muscles, joints, ligaments and fascia (position, passive movement and vibration) |
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Where must all conscious sensation reach |
The sensory area in the post central gyrus |
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The sensory area of each cerebral hemisphere receives sensation from where |
The opposite half of the body |
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Every sensation is transmitted from the receptors to the sensory area by ___ neurons |
3 neurons |
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Where does all sensation lie for the first order neuron |
all sensation lies in the dorsal root ganglion |
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Define and describe the processes of the first order neuron |
peripheral process receives sensation from the receptors Central process trasmits sensation to the second order neuron |
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What are the two possible locations of the second order neuron? In what types of sensation is each used |
spinal cord: pain, temp, touch
Medulla: proprioception and fine touch |
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What must second order neurons do to reach the thalamus |
Second order neurons must cross the midline to reach the thalamus of the opposite side |
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Where is the third order neuron located |
for all sensations the third order neuron is in the posterolateral ventral nucleus of the thalamus (PLVNT) on the OPPOSITE side |
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Where do axons of the cells in the pLVNT transmit sensation to |
The sensory area in the post central gyrus. |
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What are the possible lesions if a patient presents with sensory loss on the contralateral side |
lesion could be in: -the sensory area of the cerebral cortex -third order neuron in the thalamus -leminscus (ascending axons of second order neurons after they have crossed) |
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What are the possible lesions if a patient presents with sensory loss on the ipsilateral side |
lesion is in the first order neuron |
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What are the afferent sensory fiber types |
general somatic sensory (GSS): exteroceptive and enteroceptive to CNS General visceral sensory (GVS): viscera to CNS special somatic sensory (SSS): ear and eye to CNS Special visceral sensory (SVS): taste and smell to CNS |
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What are the efferent motor fibers |
General somatic motor (GSM): CNS to striated muscle General Visceral Motor (GVM): CNS to smooth muscle, heart and glands Special visceral motor (SVM): CNS to special visceral muscles |
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Describe the pathway of the first order neuron for vibration, proprioception and fine touch |
through the dorsal root ganglia the central process enters the spinal cord and ascends in the posterior column in the gracile (lower 1/2) or cuneate (upper 1/2) |
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Describe the pathway of the second order neuron for vibration, proprioception and fine touch |
The gracile or cuneate nuclei in the medulla. Their axons form internal arcuate fibers which cross in the medulla and then ascend on the opposite side as the medial lemniscus. The medial lemniscus ascends to end in posterolateral ventral nucleus of the thalamus (PLVNT) |
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Describe the pathway of the third order neuron for vibration, proprioception and fine touch |
posterolateral ventral nucleus of the thalamus (PLVNT). The axons of these cells ascend as sensory radiation. They pass in the posterior half of the posterior limb of the internal capsule to reach the post central gyrus |
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What diagnosis would you be considering if a patient presents with loss of proprioception (sensory ataxia) manifested by high stepping and unsteady gait? |
Tabes dorsalis: a syphilitic lesions in the dorsal column |
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Describe the first order neuron for pain and temp below the head |
From the dorsal root ganglia the central processes enters the spinal cord and ascends or descends for one segment before relaying in the substantial gelatinous of rolandi which then forms Lissauer's tract |
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Describe the second order neuron for pain and temp below the head |
From the substantial gelatinous of rolandi these axons cross to the opposite side and ascend as the lateral spinothalamic tract and ascends through the brainstem together with the ventral spinothalamic tract forming the spinal lemniscus which then ascend to end in the PLVNT (posterolateral ventral nucleus of the thalamus) |
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Describe the third order neuron for pain and temp below the head |
from PLVNT these axons ascend as sensory radiation. They pass in the posterior half of the posterior limb of the internal capsule to reach the post central gyrus |
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Define and describe a syringomyelia |
lateral spinothalamic tract lesion: enlargement in the central canal of the spinal cord due to fusion of the central canal with cysts in the grey matter surrounding it (hydromyelia). The second order neuron of pain and temp are affected as they cross in front of the central canal causing selective loss of pain and temp but light touch and proprioception are preserved. This is termed dissociated sensory loss. |
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Describe the differences between pain and temp vs crude touch below the head. |
Crude touch: second order neuron is nucleus proprius and they cross at the same level instead of one above or below. After crossing they ascend in the anterior spinothalamic tract. Rest is the same. |
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Pain is going to go to the cortex for processing in one of five areas. What are these five areas and what do they each uniquely do. |
1.somatosensory cortex: conscious recognition, appreciation, analysis, localization and previous experience. 2. cingulate gyrus: emotional 3. insular cortex: autonomic response (sweating) 4. reticular formation of brain stem to alert the cerebral cortex 5. intralaminar nuclei of thalamus to alert the cerebral cortex (yes, same as 4) |
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what is the pathway for sensation from the head |
The trigeminal pathway |
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The trigeminal ganglion splits into three nuclei. What are the nuclei and what are their functions? Which order neurons are these |
1. main sensory nucleus: crude touch 2. Spinal nucleus: pain and temp 3. mesencephalic nucleus: proprioception and fine touch
First order neurons |
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Describe the second order neurons of the trigeminal pathway (sensation from head) |
Axons of the three trigeminal nuclei cross to the opposite side and ascend as the trigeminal lemniscus and ascends through the brainstem to the PMVNT |
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Describe the third order neurons of the trigeminal pathway |
PMVNT axons ascend in the posterior limb of the internal capsule to reach the post central gyrus |
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Describe posterior cord syndrome and anterior cord syndrome |
Posterior cord: lesion in posterior column means loss of vibration and proprioception
Anterior cord: lesion in anterior column means loss of pain, temp and motor |
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Describe transverse cord lesion (severed cord) and hemicord lesion (partial severed cord) |
Transverse cord: loss of everything below level of lesion
Hemicord: pain and temp loss contralateral and vibration, proprioception and motor loss ipsilaterally. |
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Describe Central cord syndrome small and large lesions |
small: affects arm pain and temp first
Large: affects everything below the lesion. |
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What are the four unconscious pathways |
dorsal spinocerebellar ventral spinocerebellar cuneocerebellar rostral spinocerebellar |
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Describe the path of the dorsal spinocerebellar |
First order: dorsal root ganglion Second order: dorsal nucleus of clark Crossing: no Cerebellar peduncle: inferior Limb: lower limb same side |
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Describe the path of the ventral spinocerebellar tract |
First order: dorsal root ganglion Second order: spinal border nucleus Crossing: crosses then re-crosses Cerebellar peduncle: superior Limb: lower limb same side |
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Describe the path of the cuneocerebellar tract |
First order: dorsal root ganglion Second order: accessory cuneate nucleus Crossing: no Cerebellar peduncle: inferior Limb: upper limb same side |
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Describe the path of the rostral spinocerebellar tract |
First order: dorsal root ganglion Second order: spinal border nucleus Crossing: no Cerebellar peduncle: superior Limb: upper limb same side |
