12-2 DESCENDING NS Pathways Flashcards Preview

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Flashcards in 12-2 DESCENDING NS Pathways Deck (12):
1

A: Cells of Origin for [Area 4 precentral gyrus] are called the ____ ____ ____. So...Corticospinal Tract is AKA ____ Tract B: CST starts in _______--->forms ___ ____--->which travels in Internal Capsule----> _________ --->________ inside Pons -----> decusates in ___ _____---(travels in) -->____ ______ as the ________---> synapse on [ANT horn cells] C1: 10% of CST fibers DON'T CROSS AT [___ ____] These are called the ____ C2: These ______ cross over at diff levels of the __ _____to still synapse on contralateral [ANT horn cells] like the _________ D: CST Fibers are ____[Upper/lower] Motor Neurons and is the ___[smallest/Largest] Descending Tract E: CST is used for what type of movements?


A: Cells of Origin for [Area 4 precentral gyrus] = [Pyramidal Betz Cells] (In the Medulla). So...Corticospinal Tract is AKA Pyramidal Tract B: CST starts in [Area 4 precentral gyrus]--->forms [CORONA RADIATA]--->travels in Internal Capsule----> [Crus Cerebri Cerebral Peduncle] --->[Base of the Pontine Gray] -----> decusates in medullary pyramid---(travels in)-->[Lateral funiculus] as the [Lateral CST]---> synapse on [ANT horn cells] C1: 10% of CST fibers DON'T CROSS AT [medullary pyramids= [ANT CST] . C2:[ANT CST] crosses over at diff levels of [Ventral Funiculus] to still synapse on contralateral [ANT horn cells] like the [Lateral CST] D: CST Fibers are Upper Motor Neurons and is the LARGEST Descending Tract E: CST is used for Fine movements like piano playing/picking up pennies


2

[T or F] Cerebellar Lesions can be characterized as "Motor problems with NO Muscle Weakness"

TRUE!

3

A: What does the CST synapse once it reaches ___ horn



B: Why 2 nuclei occupy the same space in the high cervical cord?


A: Synapse on Large [ANT horn cells] of medial and lateral motor nuclei of spinal cord Ventral Horn



B: Spinal Accessory nucleus (C1-C5) and Phrenic nuclei(C3,4,5) occupy SAME area in high cervical cord


4

1. Pyramidal Cells (of Area 4) are also called ___ Cells! These are the Cells of __ Origin in the _______ -------------------------------------------------------------------------------------- 2. As CST axons come out of __ ____ cells in the _______ they first form a Circular Crown called the ___ _____. This then travels in the ______ _______ ___ ______ and descends downward into the _____ of the ___----> _______ inside the Pons


1. Pyramidal Cells (of Area 4) are also called Betz Cells! These are the Cells of Motor Origin in Area 4. 



2. As CST axons come out of [Pyramidal Betz Cells] in [Area 4 Precentral Gyrus] they form a Circular Crown= [CORONA RADIATA]. This then travels in the POSTERIOR LIMB>Internal Capsule and descends downward into the [Crus Cerebri Cerebral Peduncle] of Midbrain----> [Base of the Pontine Gray] inside Pons


5

UPPER motor neuron lesions result in ____, _____ and ________


UPPER motor neuron lesions result in {HES} 1. SPASTIC PARALYSIS 2. Exaggerated Reflexes 3. Hemiplegia (1 sided paralysis)


6

A: lower motor neuron lesions result in ____, _____ and ________



B: Which cells are the LOWER motor neurons?


lower motor neuron lesions result in {fOf] 1. flaccid PARALYSIS 2.hypOreflexivity 3. fasciculations



B: [ANT Horn Cells] and their axons


7

Gluteus MAX has a ___[Many/few] Large motor units because _________
vs.
Flexor Digi Profundus which has ___[Many/few] Large motor units because_____

Gluteus MAX has a few Large motor units because its actions ARE NOT precise
vs.
Flexor Digi Profundus which has MANY Large motor units

8

[ALS & Polio] causes the degeneration of ____ and ____. These affect ____[UPPER/lower] motor neuron activity MORE! What type of sx would this cause? [3]


ALS/Polio causes the degeneration of [ANT Horn cells] and [Pyramidal Betz cells]. This affects the lower motor neuron activity MORE = fOf 1. flaccid paralysis 2. hypOreflexivity 3. fasciculations


9

A: In what 2 instances do you see a POSITIVE Babinski Sign



B: What does a POSITIVE Babinski Sign look like? [2]


POSITIVE Babinski Sign



1. [UPPER Motor Neuron] damage --> {HES} sx



2. infants



B: Pt [Hallux DORSIflexes] & toes fan out


10

A: Why is the interpeduncular Fossa significant? Where is it located?



B: The [SUP cerebellar Peduncle] decusates in the [Caudal MIDBRAIN]


A: The interpeduncular Fossa is significant because [Oculomotor CN3] runs out of it. It is found in the MIDBRAIN between the 2 [Crus Cerebri Cerebral Peduncle} 



B: The [SUP cerebellar Peduncle] decusates in the [Caudal MIDBRAIN]


11

1. Which 2 tracts cross in Medulla?



2. Sympathetics are found in the ____



3. Medial and Lateral motor nuclei are related to the ____ Tract



4. Which 2 tracts uses the [inferior Cerebellar peduncle] (ICP)?



5. DSCT uses ___ Nucleus before going to _____



6. ___, ____ and ____ tracts all cross in the Spinal Cord



7. Medial Lemniscus uses the ____ _____ pathway



8. Nucleus Proprius is related to the ___ ____ Tract


1. CST and DCP = cross in Medulla



2. Sympathetics are found in the [Lateral Horn/IML]



3. Medial and Lateral motor nuclei are related to the CORTICOSPINAL TRACT (CST)



4. DSCT & CCT use ICP [Remember: VSCT uses SCP]



5. DSCT uses Clark's Nucleus before going to ICP



6. VSCT / [ANT CST]/ STT all cross in the Spinal Cord



7. Medial Lemniscus uses the [Dorsal Column Pathway]



8. Nucleus Proprius is related to the [Spinal Thalamic Tract]


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