Spinal Cord PDF

Spinal cord Study online at https://quizlet.com/_e976e9 1. Describe the 2 posterior spinal arteries spinal cord's cir- - Perfuses the posterior 1/3 of the spinal cord culation 1 anterior spinal artery - Perfuses the anterior 2/3 of...

Spinal cord Study online at https://quizlet.com/_e976e9 1. Describe the 2 posterior spinal arteries spinal cord's cir- - Perfuses the posterior 1/3 of the spinal cord culation 1 anterior spinal artery - Perfuses the anterior 2/3 of the spinal cord 6 - 8 radicular arteries 2. What is - It's the largest and most important radicular artery. the Artery - It perfuses the anterior spinal cord in the thoracolumbar of Adamkiewicz region. (Great Radicular Artery)? There is significant person-to-person variation: - It most commonly originates on the left side between T11-12. 3. What is Anteri- An aortic cross-clamp placed above the artery of or Spinal Artery Adamkiewicz can cause ischemia to the lower portion of Syndrome? the anterior spinal cord. This can result in anterior spinal artery syndrome - other- wise known as Beck's syndrome. 4. What are S/S of Flaccid paralysis of the lower extremities Anterior Spinal - The corticospinal tract is perfused by the anterior blood Artery Syn- supply. drome? Bowel and bladder dysfunction - Autonomic motor fibers are perfused by the anterior blood supply. Loss of temperature and pain sensation - The spinothalamic tract is perfused by the anterior blood supply. Preserved touch and proprioception - The dorsal column is perfused by the posterior blood supply. 1 / 10  Spinal cord Study online at https://quizlet.com/_e976e9 5. Where do sen- Sensory neurons from the periphery enter the spinal cord sory/motor fibers via the dorsal nerve root, while motor and autonomic enter/exit the neurons exit via the ventral nerve root. spinal cord? 6. Describe Gan- Ganglion glion, Grey & - A ganglion is a collection of cell bodies that reside outside White Matter. of the CNS. Grey Matter - The grey matter contains neuronal cell bodies. White Matter - Contains the axons of the ascending and descending tracts. 7. Describe the gray - The grey matter is subdivided into 10 laminae. matter laminae - Laminae 1 - 6 reside in the dorsal grey matter. These are sensory. - Laminae 7 - 9 reside in the ventral grey matter. These are motor. - Lamina 10 is around the central canal; anterior and posterior commissures comprise lamina 10. 8. In what regions - The grey matter is larger in two specific regions of the is the grey matter spinal cord. larger? - The region of cervical enlargement (C5 - C7) contains the cell bodies for the neurons that supply the upper extremities. 2 / 10  Spinal cord Study online at https://quizlet.com/_e976e9 - The region of lumbar enlargement (L3 - S2) contains the cell bodies for the neurons that supply the lower extremi- ties. 9. State the tracts of Sensory the spinal cord? - Dorsal column (Cuneatus and Gracilis): Fine touch and What is their proprioception function? - Spinothalamic Lateral spinothalamic tract: Pain and temperature Ventral spinothalamic tract: Crude touch and pressure Motor - Ventral corticospinal tract: Posture motor - Lateral corticospinal tract: Limb motor 10. What is trans- - Transmits: fine touch, proprioception, vibration, and pres- mitted by the sure Dorsal Column - Capable of two-point discrimination - a high degree of tract? Describe localizing the stimulus. the conducting - Consists of large, myelinated, rapidly conducting fibers. fibers, velocity, - Transmits sensory information faster than the anterolat- and ability of eral system. discriminate two points 11. Describe the First-Order Neuron: A-beta nerve fiber anatomy of the - Enters the spinal cord through the dorsal root ganglion. Dorsal Column - Ascends the spinal cord on the ipsilateral side and tract synapses with the second-order neuron in the medulla (cuneate and gracile nuclei). Second-Order Neuron: cuneate and gracile nuclei - Crosses to the contralateral side in the medulla, then ascends towards the thalamus via the medial lemniscus. - Synapses with the third-order neuron in the thalamus - 3 / 10  Spinal cord Study online at https://quizlet.com/_e976e9 the ventral posterolateral (VPL) and ventral posteromedial nuclei (VPM) Third-Order Neuron: VPL and VPM nuclei - These fibers pass through the internal capsule and ad- vance towards the somatosensory cortex in the postcen- tral gyrus in the parietal lobe. 12. What is trans- - Transmits: pain, temperature (lateral) and crude touch, mitted by pressure (ventral) the spinothala- - Consists of smaller, myelinated, and nonmyelinated, mic tract? De- slower conducting fibers. scribe the con- - Transmits sensory information 1/2 to 1/3 as fast as the ducting fibers, dorsal column (medial lemniscal system). velocity, and abil- - Two-point discrimination is not present. ity of discrimi- nate two points 13. Describe the First-Order Neuron anatomy of - A-delta: "first" pain, mechanoreceptors the Spinothalam- - C-fibers: "slow" pain, polymodal nociceptors ic tract - The cell body is in the dorsal root ganglion. - May ascend or descend 1 - 3 levels on the ipsilateral side in the Lissauer tract before synapsing with the second-or- der neuron. - Pain neurons synapse with the second-order neuron in the substantia gelatinosa - Rexed's lamina 2 Second-Order Neuron - Crosses to the contralateral side of the spinal cord, then ascends towards the brain via two pathways: Lateral spinothalamic (Neopinothalamic) tract - trans- mits pain and temperature Anterior spinothalamic (Paleospinothalamic) tract - crude touch and pressure 4 / 10  Spinal cord Study online at https://quizlet.com/_e976e9 - Cell bodies reside in the dorsal horn of the spinal cord. - Second-order neurons synapse with third-order neurons in the reticular activating system and the thalamus. Third-Order Neuron - Most tactile signals are relayed to the ventrobasal com- plex of the thalamus. - These fibers pass through the internal capsule and ad- vance towards the somatosensory cortex in the postcen- tral gyrus in the parietal lobe. 14. What is transmit- Its primary functions include voluntary fine motor ted by the Cor- control to the limbs and coordination of posture. ticospinal (Pyra- midal) Tract? 15. Describe the cor- Motor neurons exit the precentral gyrus of the frontal lobe, ticospinal tract pass through the internal capsule, and then travel inferiorly pathway through the pyramids of the medulla. Lateral corticospinal - Innervate the limbs - Crossover to the contralateral side in the medulla. Ventral corticospinal - Innervate the axial muscles - Remain on the ipsilateral side as they descend - Crossover to the contralateral side of the spinal cord when they reach the cervical or upper thoracic area. 5 / 10  Spinal cord Study online at https://quizlet.com/_e976e9 16. What are up- The upper motor neurons begin in the cerebral cortex and per motor neu- synapse with the lower motor neurons in the ventral horn rons? What are of the spinal cord. the signs of in- jury? Give exam- Upper motor neuron injury ’ contralateral spastic paralysis ples + hyperreflexia Examples: cerebral palsy and amyotrophic lateral sclero- sis. 17. What test as- The Babinski test sesses the in- - Negative test (corticospinal tract is intact) - a firm stim- tegrity of the cor- ulus to the underside of the foot produces a downward ticospinal tract? motion of all the toes. How is it inter- - Positive test (damage to the corticospinal tract) - a firm preted? stimulus to the underside of the foot produces an upward extension of the big toe with fanning of the other toes. 18. What are low- The lower motor neurons begin in the ventral horn and end er motor neu- at the neuromuscular junction. rons? What are the signs of in- Lower motor neuron injury ’ ipsilateral flaccid paralysis and jury? impaired reflexes 19. How is the Babin- Absent ski reflex with lower motor neu- ron injury? 20. What do SSEPs SSEPs monitor the integrity of the dorsal column (medial monitor? lemniscus). - The posterior spinal arteries perfuse this region of the cord. - SSEPs do not monitor the anterior cord, so they aren't interchangeable with MEPs. 6 / 10  Spinal cord Study online at https://quizlet.com/_e976e9 21. What do MEPs MEPs monitor the integrity of the corticospinal tract. monitor? - The anterior spinal artery perfuses this region of the cord. 22. What are the S/S Damage to upper motor neurons of a complete - Flaccid paralysis spinal cord in- - Loss of sensation below the level of injury. jury? - Loss of bowel and bladder function After the acute phase: spinal reflexes return, which leads to spasticity. Hemodynamic instability ’ neurogenic shock - Greatest with injuries to the cervical or upper thoracic cord. - The higher the injury, the greater the degree of hemody- namic instability. 23. What are S/S SCI ’ Sympathectomy below the level of injury of neurogenic shock “ SNS tone ’ Vasodilation - Venous pooling, “ CO, and hypotension - Cutaneous heat loss and hypothermia Impairment of cardioaccelerator fibers (T1 - T4) - Unopposed vagal tone - Bradycardia and reduced inotropy Triad: hypotension, bradycardia, and hypothermia 24. How to dif- Neurogenic Shock ’ bradycardia, hypotension, hypother- ferentiate neuro- mia with pink, warm extremities genic from hypo- volemic shock? Hypovolemic shock ’ tachycardia, hypotension, and cool, clammy extremities 25. How to treat neu- Norepinephrine is a good choice to restore SVR and in- rogenic shock? otropy. Volume expansion is required as well 7 / 10  Spinal cord Study online at https://quizlet.com/_e976e9 26. Can succinyl- Although succinylcholine should be avoided 24 hours after choline be used injury (due to upregulation of extrajunctional receptors), in patients fasciculations may worsen outcomes with SCI. with neurogenic shock? For this reason, it's prudent to forego the use of succinyl- choline altogether. 27. What are the ma- Ineffective alveolar ventilation and the inability to clear jor causes of pulmonary secretions. morbidity and mortality in pa- tients with cer- vical and upper thoracic lesions? 28. What happens After the spinal shock phase ends (1 - 3 weeks) with chronic - Return of spinal sympathetic reflexes below the level of SCI? injury - NO inhibitory influences that would normally come from above the level of injury - Overreactive SNS below level of injury ’ risk for autonomic hyperreflexia (mass reflex). - More likely with injuries > T6 - Less likely with injuries < T10 29. What are com- - Stimulation of the hollow organs - bladder, bowel, or mon events that uterus cause AH? - Bladder catheterization - Surgery - especially cystoscopy or colonoscopy - Bowel movement - Cutaneous stimulation - Childbirth 30. How does AH oc- Stimulation below the level of SCI triggers a sympathetic cur? reflex arc that creates a profound degree of vasoconstric- tion below the level of injury. This activates the baroreceptor reflex in the carotid si- nuses, which slows the heart rate. The body attempts to reduce afterload with vasodilation above the level of injury. 8 / 10  Spinal cord Study online at https://quizlet.com/_e976e9 31. What is the pre- Classic presentation: hypertension and bradycardia. sentation of AH? Other signs and symptoms include: - Reflex vasodilation above the level of spinal cord injury - nasal stuffiness. - Hypertension ’ headache and blurred vision. - Stroke, seizure, left ventricular failure, dysrhythmias, pul- monary edema, and myocardial infarction. 32. What is the most Prevent stimulation below the level of injury important con- sideration in AH? 33. Compare GA, - General or spinal anesthesia is the best option. spinal, and - An epidural may be used for a laboring mother; however, epidural in pa- when compared to a spinal anesthetic, an epidural tients with SCI does not inhibit the sacral nerve roots to the same degree. 34. Is Succinyl- Succinylcholine is contraindicated in patients with chronic choline safe in SCI. patients with SCI? 35. How to treat Hypertension is best treated with: HTN and brady- - Removal of the stimulus. cardia secondary - Deepening the anesthetic. to MH? - A rapid-acting vasodilator, such as sodium nitroprusside. Bradycardia can be treated with atropine or glycopyrrolate. 36. Describe the Amyotrophic lateral sclerosis (ALS) causes progressive pathophysiology degeneration of motor neurons in the corticospinal tract. of Amyotrophic Lateral Sclerosis Astrocytic gliosis replaces the affected motor neurons. The upper and lower motor neurons are affected. 37. What are the S/S Upper neuron involvement: spasticity, hyperreflexia, and of ALS? loss of coordination. 9 / 10  Spinal cord Study online at https://quizlet.com/_e976e9 Lower motor neuron involvement: muscle weakness, fas- ciculations, and atrophy. Characteristics of weakness - It often begins in the hands. Over time, weakness spreads to the rest of the body, affecting the tongue, pharynx, larynx, and chest. - The ocular muscles are not affected. Autonomic dysfunction: orthostatic hypotension and rest- ing tachycardia. Sensation remains intact. 38. What drug is Riluzole (an NMDA receptor antagonist) is the only drug used in the treat- that reduces mortality. ment of ALS? What is the most Respiratory failure is the most common cause of death. common cause of death? 39. How are NMBs Succinylcholine can cause lethal hyperkalemia (prolifera- dosed in ALS? tion of postjunctional nicotinic receptors). Nondepolarizing neuromuscular blockers: increased sen- sitivity 40. What are the Risk of pulmonary aspiration: Bulbar muscle dysfunction main considera- tions in patients “ Vital Capacity and MV: dues muscle weakness with ALS? Consider postoperative mechanical ventilation. 10 / 10