Term
| what are striated muscles innervated by? |
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Definition
| motor neuron pools in the ventral horn of the spinal cord or the brainstem |
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Term
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Definition
| all the muscles innervated by one neuron in the pool |
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Term
| where are upper motor neurons? |
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Definition
| cerebral cortex or brainstem |
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Term
| describe to connections between UMN and LMN |
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Definition
| direct or through interneuron |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| rubrospinal, reticulospinal, tectospinal, vestibulospinal, sensory reflex arcs |
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Term
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Definition
| spastic paralysis (reflex and supraspinal input intact), can not fire LMN voluntarily |
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Term
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Definition
| biochemical stimulation of muscle by LMN maintains muscle |
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Term
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Definition
| UPM, lesions of immature brain |
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Term
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Definition
| flaccid paralysis; no firing; no voluntary or involuntary control; neurotrophic effect lost |
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Term
| what is an example of a LMN disease where a virus and inflammatory cells destroy motor neurons in the anterior horn or brainstem |
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Definition
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Term
| name five patterns of plegias |
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Definition
| quadraplegia, para(lower)plegia, hemiplegia, upper diplegia, and lower diplegia |
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Term
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Definition
| integrate and regulate UPM input |
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Term
| what kind of neuron integrates all direct and indirect synaptic input from UMNs, interneurons and sensory afferents? |
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Definition
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Term
| what is the collateral recurrent feedback loop of the alpha motor neuron? |
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Definition
| alpha --> renshaw --> inhibit alpha |
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Term
| does the Renshaw act only on a single alpha motor neuron? |
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Definition
| no --> it acts on its parent and other alpha motor neuron cell bodies |
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Term
| describe lumbar level ventral horn somatotopy |
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Definition
medial to lateral --> proximal to distal (hip thigh leg foot)
ventral--> extensor
dorsal --> flexor |
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Term
| where are flexor and extensor MN pools located in the ventral horn? |
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Definition
| flexors are dorsal medial and extensors are ventral lateral |
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Term
| what are the two levels of somatotopy in the ventral horn related to? |
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Definition
| distance from midline and function; extensors are ventral, flexors dorsal; axial is medial and distal is lateral |
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Term
| is sensory input to alpha motor neurons only ipsilateral? |
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Definition
| no, it is both ipsi and contralateral |
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Term
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Definition
| in series with muscle, feedback about muscle tension, located at muscular/tendon junction |
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Term
| what provides feedback to amn about length and stretch? |
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Definition
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Term
| what innervates intrafusal muscle fibers? |
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Definition
| gamma motor neurons; intrafusal contraction keeps receptor of muscle spindle in its most sensitive range |
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Term
| intrafusals and extrafusal must contract at the same time, what does this imply? |
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Definition
| that alpha and gamma motor neurons are coactivated |
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Term
| morphology of psotganglionic C fibers |
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Definition
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Term
| Aa, Ab, Ad, C, what are these categories? |
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Definition
| afferent fibers --> Aa (reflex) Ab (discriminative touch), Ad(fast pain/temp), C (slow pain/temp) |
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Term
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Definition
| flex same and synergist muscles, relax antagonist |
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Term
| flexor crossed extensor reflex |
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Definition
| withdrawl response; stimulation to both ipsilateral and contralateral synergists and antagonists; describe this action |
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Term
| weakens or paralyses muscles, absent tone, eliminates reflexes, full muscle atrophy from disuse |
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Definition
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Term
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Definition
| corticobulbospinal tract, but some refer to the whole pyramidal tract as corticobulbospinal tract or CBST |
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Term
| give three areas of cortex where corticospinal traxt axons originate |
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Definition
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Term
| where do most CST axons originate? |
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Definition
| pyramidal cells of cortex layer 5 |
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Term
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Definition
| layer five giant pyramidal neurons |
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Term
| track of corticospinal fibers |
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Definition
| cortex--> corona radiata --> PLIC --> 85% decussate in brainstem (upper body decussates rostral...lower limbs decussate caudal) |
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Term
| somatotopy of CST in crus cerebri |
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Definition
| medial arm to lateral leg (same as peduncle) |
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Term
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Definition
| upper limb medial, lower limb lateral |
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Term
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Definition
| formed by decussation of SCT (85-90% decussate)descends in the lateral white matter |
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Term
| somatotopy of LCST in cord |
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Definition
| upper limb medial and lower limb lateral |
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Term
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Definition
| intermediate gray and lateral ant horn; is used for distal muscles and fine movements |
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Term
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Definition
| medial anterior gray horn; decussates in anterior white commissure --> is bilateral for axial and proximal muscles |
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Term
| why would axial muscles have bilateral stimulation? |
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Definition
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Term
| test for pyramidal tract health in babies |
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Definition
| Bainski sign (under 1-2 years the tract is still unmyelinated) |
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Term
| CST UPM lesion will result in which positive sign? |
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Definition
|
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Term
| what fibers cross the midbrain immediately after initiation of descent? |
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Definition
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Term
|
Definition
| rubrospinal tract location in cord, ventrally adjacent to LCST in lateral white matter; generally terminate in flexor pool in dorsal medial ant horn |
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Term
| what ep tract allows reflex to visual stimulus? |
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Definition
| tectospinal fibers from superior colliculus, decussate in Dorsal |
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Term
| where does tectospinal tract end? |
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Definition
| axial muscles for the head and neck, dorsal medial anterior horn of upper cervical segments |
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Term
| pontine reticulospinal fiber tract excites what? |
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Definition
| axial (and extensor?) neuron pools |
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Term
| medullary reticulospinal tract is excitatory to what? |
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Definition
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Term
| vestibulospinal tract; descends in lateral funiculus and bilaterally in medial funiculus (begins in vesticular nuclei in rostral medulla |
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Definition
| lateral --> postural extensor neurons and medial --> neck muscles for head stabilization and coordination with eyes |
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Term
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Definition
| UMN lesion above red nucleus no inhibition of either uper arm flexor or lower limb extensor tracts (u-flexed, lower - extended) |
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Term
|
Definition
| UMN lesion below red nucleus,flexor tract is lost to upper extremities but lower limb extensors go unopposed |
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Term
| what muscle actions are coordinated through cranial nerve nuclei? |
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Definition
| eye movement, swallowing, facial expression, vocalization, chewing, tongue movement |
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Term
| what muscle movements are coordinated through ventral spinal gray? |
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Definition
| axial, appendicular, diaphragm |
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Term
| what are the modalities of the motor cortex? |
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Definition
| planning, decisions, directives, context |
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Term
| what are the modalities of the basal nuclei? |
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Definition
|
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Term
| what are the modalities of the basal nuclei? |
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Definition
|
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Term
| what are the motor modalities of the brain stem? |
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Definition
| integration, reflexes coordination, and final output(cranial nerves only) |
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Term
| What are the motor modalities of the cerebellum? |
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Definition
| contraction monitoring and fine tuning |
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Term
| what are the motor modalities of the intermediate and ventral horn of the spinal cord? |
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Definition
| integration, reflexes, pattern wiring, and final output |
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Term
| muscles that are used for fine movements have more or less motor units? |
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Definition
| more, smaller motor units |
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Term
| head movements are controlled by alpha motor neurons from what structures? |
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Definition
| ventral forn of cervical spinal cord |
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Term
| what is another term for sensory neurons that synapse with LMN? |
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Definition
|
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Term
| name three inputs to interneurons (lamina 8) of the spinal gray |
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Definition
| other interneurons, sensory neurons and supraspinal neurons |
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Term
| is the MSR mediated by the GTO? |
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Definition
|
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Term
| describe the effect of an upper motor neuron lesion on the MSR |
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Definition
| initially weak, upon recovery exaggerated (hyperflexia) |
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Term
| What kind of receptor stimulates the Flexor-Withdrawl reflex? |
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Definition
|
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Term
| Describe how nociception gives rise to a polysynaptic reflex during the FWR. |
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Definition
| Nociceptive fibers give off collaterals to interneurons that stimulate and inhibit the appropriate muscles. alpha motor neuron will be inhibited if the last interneuron to it is inhibitory??? |
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Term
| What is a central pattern generator? |
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Definition
| complex patterns in cord that produce rhythmical movements (snake can walk with its head cut off) |
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Term
| why do fasciculations occur as LMN are dying? |
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Definition
| They spontaneously depolarize causing contraction. |
|
|
Term
| name the four extrapyramidal supraspinal tracts |
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Definition
| rubrospinal, tectospinal, vestibulospinal, and reticulospinal |
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Term
| what is the somatotopy of the CST in the PLIC |
|
Definition
| Neck anterior in sequence... leg posterior in the middle 1/3/ of the capsule |
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Term
| what is the somatotopy of the CST in the cerebral penduncle? |
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Definition
| neck medial towards interpeduncular fossa... leg lateral |
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Term
| What percent of the UMN in the lateral funiculus synapse on alpha motor neurons? |
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Definition
|
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Term
| clasp knife reflex and is a sign of what type of lesion? exaplain |
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Definition
| UMN.. no inhibition of reflex action patterns (clasp knife is rigid flexion on slight passive stretch that slowsly loosens, GTO is overactive) |
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Term
| ACST lesion are often unnoticeable. Why? |
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Definition
| because they are bilateral... there is back-up if one side is lost. |
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|
Term
| what does a lesion in the CST at the pyramids produce? |
|
Definition
| voluntary paralysis on both sides |
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|
Term
| tectospinal tract ends where? |
|
Definition
| it ends in the ventral funiculus, near anterior commissure in the cervical cord |
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Term
| which part of the red nucleus does the rubrospinal tract originate from? |
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Definition
| the caudal, large celled part |
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