Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Neuroanatomy Lab 6
Motor Systems
| Question | Answer |
|---|---|
| Corticospinal descending motor tract: give origin, position of motor neurons, and muscles affected; mnemonic to remember postion | Cortex, most lateral, most distal; cory rubs red vests (lateral to medial) |
| rubrospinal descending motor tract: give origin, position of motor neurons, and muscles affected | red nucleus, a bit less lateral, a bit less distal |
| reticulospinal descending motor tract: give origin, position of motor neurons, and muscles affected | reticular formation, medial, more axial |
| vestibulospinal descending motor tract: give origin, position of motor neurons, and muscles affected | vestibular nuclei, most medial, most axial |
| muscle control: cerebellum vs. cortex | cerebellum exerts its control over the ipsilateral side of the body, whereas the cortex exerts its control generally over the contralateral side of the body |
| 3 main lobes of the cerebellum, and the fissures that separate them | flocconodular lobe is separted from the posterior lobe by the larger posterolateral fissure; posterior lobe and anterior lobe are separated by the primary fissure |
| how many lobules does the cerebellum have? | 10 |
| superior view of cerebellum: positions of vermis, paravermis, and cerebellar hemispheres | vermis--most medial |
| connections between inferior cerebellar peduncle and cerebellum | inputs from spinal cord and brainstem; bi-directional connections of cerebellum and vestibular nuclei; projections from cerebellum to the reticular nuclei |
| middle cerebellar peduncle inputs to cerebellum | cerebellar inputs from contralateral pontine nuclei |
| superior cerebellar peduncle and cerebellum | mainly outputs from cerebellum |
| how does the middle cerebellar peduncle connect to the cerebellum? | laterally and posteriorly |
| three functionally distinct parts of cerebellum | spinocerebellum, vestibulocerebellum, and cerebrocerebellum |
| what inputs are received by the cerebrocerebellum? | contralateral pontine nuclei via the middle cerebellar peduncle |
| outputs of cerebrocerebellum | project back to motor and premotor cortical areas after stopping in VL thalamus |
| what is the cerebrocerebellum involved in? | motor planning and initiation of movement |
| what is the function of the spinocerebellum? | coordinate motor control during motor execution |
| what region of the cerebellum does the spinocerebellum refer to? | vermis and paravermis |
| what does vermis coordinate? | medial (axial) systems |
| what input does the vermis receive? | vestibular and reticular nuclei and proprioceptive and sensory inputs from the head and neck |
| what does paravermis control? | activity of lateral motor systems (limb movement) during ongoing motor activity |
| what information does paravermis receive? | information on limb position from the spinal cord (ascending spinocerebellar tracts) |
| what lobe does the vestibulocerebellum occupy? | flocculonodular lobe |
| Whence does the vestibulocerebellum receives its input? | vesitibular nuclei |
| main efferent projection of vestibulocerebellum? | back to vestibular nuclei |
| what is the vestibulocerebellum mainly responsible for? | coordinating eye movements and body equilibrium |
| output cells of cerebellar cortex | purkinje cells |
| which neurons of the cerebellum project axons that leave the cerebellum? | purkinje cells |
| are purkinje cells excitatory or inhibitory? | inhibitory |
| deep cerebellar nuclei to which purkinje cells make connections | Feel Good Each Day (fastigial, globose, embolliform, dentate); both embolliform and dentate are interposed nuclei |
| fastigial nucleus receives inputs from what, and projects to what? | vermis, reticular formation |
| inputs received and projected by the interposed nuclei | paravermis, red nucleus |
| inputs received and projected by the dentate nucleus | purkinje cells in cerebrocerebellum; projects to motor thalamus |
| does vestibulocerebellum project to a deep nucleus? | No |
| what cells send axons directly to vestibular nuclei | purkinje cells |
| two main excitatory outputs that converge upon purkinje cells | mossy fibers and climbing fibers |
| four main components of mossy fibers | pontine nuclei (largest), spinal cord, reticular formation (smallest), and vestibular nuclei |
| give peduncle origin and destination of all four mossy fibers: pontine nuclei, spinal cord, reticular formation, vestibular nuclei | middle, hemispheres; inferior, paravermis; inferior, vermis; inferior, vermis and clocculonodulus |
| axons of cerebellar granule cells relative to purkinje cells | fibers run perpendicular to rows of purkinje cells, leading to a diffuse mossy fiber signal |
| what contributes to the divergence of the mossy fiber signal? | parallel fibers contacts multiple purkijje cells and a single purkinje cells receives inputs from multiple parallel fibers |
| origin of climbing fibers | contralateral inferior olivary nucleus |
| peduncle through which climbing fibers travel on their way to the purkinje cells | inferior cerebellar peduncle |
| how many climbing fibers synapse on a single purkinje cell? | Just one |
| what is the possible function of collateral projections by mossy and climbing fibers? | may be to compare the strength and timing of these diffuse and direct signals |
| role of basal ganglia | receive descending motor information from motor/premotor cortex, process it, and send information on the results back to motor/premotor cortex after stopping in thalamus (VA/VL) |
| on which side of body does basal ganglia influence movement? | contralateral side |
| "striatum" | putamen and caudate nucleus |
| where do all cortical inputs to basal ganglia terminate? | caudate nucleus and putamen |
| two parts of globus pallidus | globus pallidus internal, globus pallidus external |
| basal ganglia | substantia nigra, globus pallidus, putamen, caudate nucleus |
| neurotransmitters used by substantia nigra | dopamine for pars compacta (SNc), and parts reticulata (SNr) does not, but is more functionally similar to GPi. |
| outputs of basal ganglia | GPi and SNr, which terminate on VA/VL, which then project to motor/premotor cortex through anterior limb of internal capsule |
| most imporant role for basal ganglia | gate for motor activity--to allow desired motions and to prevent undesired ones |
| two main pathways of basal ganglia output | direct pathway and indirect pathway |
| direct pathway | disinhibits command and allows it to be executed |
| indirect pathway | increases level of inhibition to prevent execution of motor command |
| principal projection and transmitter used at destination for SNc | to striatum where dopamine (DA) acts to stimulate motor activity |
| D2 receptors | enkephalin (Enk)-containing striatal neurons that inhibit the indirect pathway |
| D1 receptors | found on substance P (SP)-containing striatal neurons that participate in the direct pathway |
| common manifestation of cerebellar lesions | ataxia |
| dysmetria | errors in the range and force of movement |
| dysdiadochokinesia | inability to sustain regular repeated movements: no smooth transitions between components of comlex multi-joint movements |
| presentations of gait ataxia | delay in initiating movements with affected limb, dysmetria, dysdiadochokinesia |
| how does hypotonia present? | diminished resistance to passive limb displacements or a delay in response to rapid movements (lack of check) |
| intention tremor | characteristic of cerebellar disease; result from an inability to coordinate the activity of agonist and antagonist muscles and occur during attempts at specific motions |
| what happens if there is damage to the vestibulocerebellum? | general loss of equilibrium and balance |
| what do lesions in the cerebellar vermis lead to? | disturbances in axial muscle systems, which may manifest as titubation |
| what is titubation? | tremors in the trunk during standing or sitting |
| what is dysarthria | difficulty in articulating speech with no deficits in speech/language comprehension |
| what lesions can cause dysarthria? | vermal lesions; vermis contributes to control of facial muscles (Gk. arthron=articulation) |
| what does damage to lateral portions of cerebellum lead to? | delays i nmovement initiation and movement decomposition, as motor planning is impaired |
| what are the most severe cerebellar lesions? | affect deep nuclei and superior cerebellar peduncle |
| on what side of the body are deficits of the limb observed with cerebellar damage? | ipsilateral side |
| athetosis | slow, writhing movements of the fingers and hands (Gk. athetos, without position) |
| chorea | abrupt movements of the limbs/facial muscles (Gk. khoreia=dancing in unison, from khoros=chorus |
| ballismus | violent flailing of limbs (Gk. ballismo=dancing) |
| lesions of basal ganglia produce what kind of movements | involuntary movements |
| what four involuntary movements does a lesion in basal ganglia produce? | resting tremor=rhythmic, oscillatory movements at rest; athetosis; chorea; ballismus |
| Parkinson's disease pathophysiology | degeneration of the nigrostriatal pathway (projection from SNc to striatum) |
| Hungtington's disease pathophysiology | degeneration of cholinergic and GABA-ergic neurons in the striatum which project to GPe |
| Tardive dyskinesia pathophysiology | upregulation of dopamine receptors leading to hypersensitivity to dopamine, caused by long-term treatment with antipsychotic agents |
| hemiballismus pathophysiology | unilateral damage to the subthalamic nucleus |
Created by:
matthewthomp
Popular Anatomy sets