Term
| Ascending tracts carry information between what structures and in what direction? |
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Definition
| Spinal cord to the brainstem |
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Term
Descending tracts carry information between what structures and in what direction?
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Definition
| Forebrain and brainstem to the spinal cord |
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Term
| What is formed by propriospinal axons? |
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Definition
| Local circuitry of the spinal cord such as intersegmental reflexes |
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Term
| Long tracts are generally defined as tracts that carry information between what structures? |
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Definition
| Spinal cord and the cerebrum or brainstem |
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Term
| What are the primary spinal cord long tracts? |
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Definition
| Corticospinal, posterior (dorsal) column-medial lemniscal system, anterolateral system, spinocerebellar tracts, hypothalamospinal system |
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Term
| The corticospinal tract is part of the pyramidal system and is associated with what type nervous system control? |
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Definition
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Term
| The posterior (dorsal) columm-medial lemniscal system is associated with what nervous system responses? |
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Definition
| Descriminative touch, vibration, proprioception |
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Term
| The anterolateral systen is a spinal cord long tract used to carry what type of sensory information? |
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Definition
| Pain, temperature, crude (protopathic) touch |
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Term
| What kind of sensory information do spinocerebellar tracts convey to the cerebellum? |
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Definition
| Unconscious proprioception from muscles via muscle spindles and golgi tendon organs |
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Term
| The hypothalamospinal system is the central control of what types of neurons in the spinal cord? |
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Definition
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Term
| The major source of volitional motor control comes from what system? |
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Definition
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Term
| Neurons of the pyramidal system originate from where? |
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Definition
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Term
| The pyramidal system sends projections to what parts of the CNS? |
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Definition
| Brainstem and spinal cord |
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Term
| Cortical neurons of the pyramidal tract are called what? |
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Definition
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Term
| How are spinal cord and brainstem motor neurons that directly innervate muscle labeled? |
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Definition
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Term
| What component of the pyramidal system projects into the spinal cord? |
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Definition
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Term
| Where do axons of the corticospinal tract originate? |
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Definition
| 2/3 from the neurons in the motor cortex and 1/3 from sensory areas |
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Term
| The overwhelming majority of corticospinal axons cross the midline at the level of the foramen magnum to descend in what? |
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Definition
| Dorsal part of the lateral funiculus on the contralateral side |
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Term
| An injury to the motor area of the brain on one side produces motor deficits on which side of the body? |
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Definition
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Term
| The small amount of pyramidal axons that do not cross the midline after entering the foramen magnum form what? |
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Definition
| Anterior corticospinal tract |
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Term
| Axons of the corticospinal tract partially cross the midline at the spinal level at which they innervate motor neurons and interneurons associated with what structures? |
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Definition
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Term
| Are corticospinal axons exitatory or inhibitory to flexors? |
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Definition
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Term
Are corticospinal axons exitatory or inhibitory to extensors?
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Definition
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Term
| Corticospinal tract innervation is meant to control what types of movements in the extremities? |
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Definition
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Term
| What other descending tracts apart from the corticospinal tract contribute to normal motor function? |
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Definition
| Rubrospinal, vestibulospina, and reticulospinal pathways |
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Term
| What is the other flexor biased tract alongside the corticospinal tract? |
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Definition
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Term
| Where does the rubrospinal tract originate? |
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Definition
| Red nucleus of the rostral midbrain, crosses the midline near its origin |
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Term
| The primary function of the rubrospinal tract is to provide innervation for flexors in what part of the body? |
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Definition
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Term
| What are the extensor biased descending tracts? |
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Definition
| Vestibulospinal and reticulospinal tracts |
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Term
| The vestibulospinal and reticulospinal tracts have major effects on what type of extensor muscles? |
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Definition
| Postural muscles related to balance and proximal body muscle tone |
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Term
| Reticulospinal tracts originate froom nuclei in the brainstem reticular formation and travel in the ventral and ventral lateral funiculus in order to influence primary motor neurons supplying what muscles? |
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Definition
| Paraverterbal and limb extensors involved in muscle tone and posture |
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Term
| The two primary vestibulospinal tracts given off by vestibular nuclei that receive input of the vestibular portion of the vestibulocochlear nerve help innervate muscles that perform what actions? |
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Definition
| Extensors invovled with body posture and orientation |
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Term
| Vestibular nuclei that give rise to the vestibulospinal tracts reveive direct input from what part of the brain? |
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Definition
| Vestibular apparatus and the cerebellum |
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Term
| What systems constitute the upper motor neuron influences for visceromotor activity? |
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Definition
| Mostly hypothalamus, some brainstem |
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Term
| Upper motor neurons that influence the visceromotor activity primarily target what neurons? |
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Definition
| Preganglionic autonomic neurons of the intermediolateral cell column |
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Term
| What is the major pathway of the upper motor neurons that influence visceromotor activity via preganglionic neurons in the spinal cord? |
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Definition
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Term
| What are the ascending tracts in the spinal cord? |
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Definition
| Dorsal columns, anterolateral system, and spinocerebellar tracts |
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Term
| The dorsal columns are composed primarily by what structures? |
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Definition
| Central processes of dorasl root ganglion neurons |
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Term
| What kind of sensory input is carried by the dorsal columns? |
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Definition
| Discriminative touch, vibration, position sense, and kinesthesis |
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Term
| The dorsal column information is carried ipsilaterally in the spinal cord via what subdivisions? |
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Definition
| Fasciculus gracilis (positioned medially) and fasciculus cuneatus (positioned laterally) |
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Term
| What separates the fasciculus gracilis and fasciculus cuneatus of the dorsal column? |
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Definition
| Posterior intermediate sulcus |
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Term
| The fasciculus gracilis consists of axons of dorsal root ganglion neurons at what verterbral level? |
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Definition
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Term
| Fasciculus cuneatus contains axons of dorsal root ganglion at what verterbal level? |
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Definition
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Term
| How are axons in the dorsal columns organized? |
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Definition
| Somatotopically (medial to lateral orientation: foot/leg -> trunk -> arm/neck) |
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Term
| Where do dorsal column axons synapse? |
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Definition
| Nucleus gracilis cuneatus |
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Term
| What tract is formed by axons from the nucleus gracilis and cuneatus? |
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Definition
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Term
| At what level do axons from the nucleus gracilis and nucleus cuneatus cross the midline to form the medial meniscus? |
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Definition
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Term
| The medial lemniscus travels from its origin in the medulla to what part of the brainstem? |
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Definition
| Thalamus which then project to sensory areas of the cerebral cortex |
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Term
| The anterolateral system is a collection of tracts tha carries what type of sensation? |
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Definition
| Protopathic (pain, temperature, crude touch) |
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Term
| Where does the anterolateral system enter the spinal cord? |
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Definition
| Lateral division of the dorsal root entry point |
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Term
| Along which funiculi do tracts of the anterolateral system travel? |
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Definition
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Term
| Within which lamina of the dorsal horn do axons contributing to the anterolateral system synapse? |
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Definition
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Term
| On which side of the spinal cord do axons form the atnerolateral system? |
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Definition
| Opposite the point of entry |
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Term
| What are the two routes the anterolateral system uses to reach the somatosensory cortex? |
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Definition
| Spinothalamic tracts to the thalamus (direct route) or reticular formation collaterals via spinoreticular fibers (indirect) |
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Term
| Why are sensations carried by the anterolateral system resistant to disruptions by localized lesions? |
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Definition
| Collaterals of anterolateral system axons are given off to some local areas of the spinal cord, providing several pathways to the cerebral cortex |
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Term
| Spinocerebellar tracts carry unconscious sensation from what types of receptors found primarily in muscles and joints? |
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Definition
| Muscle spindles, joint capsules, skin |
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Term
| Spinocerebellar convey information to the cerebellum to help perform what kinds of tasks? |
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Definition
| Coordinate muscle activity |
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Term
| Spinocerebellat tracts send sensory information through the dorsal root ganglia to cells within what part of the spinal cord? |
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Definition
| Intermediate zone of the spinal grey matter |
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Term
| The spinocerebellar tract is divided into anterior, posterior, and cuneocerebellar tracts. What part of the body sends sensory information to the anterior and posterior divisions of the spinocerebellar tract? |
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Definition
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Term
The spinocerebellar tract is divided into anterior, posterior, and cuneocerebellar tracts. What part of the body sends sensory information to the cuneocerebellar division of the spinocerebellar tract?
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Definition
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Term
| Do the spinocerebellar tracts ascend the spinal cord ipsalaterally or contralaterally? |
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Definition
| Ipsilaterally for posterior and spinocerebellar, contralaterally for anterior |
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Term
| What supplies blood to the dorsal columns? |
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Definition
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