Exam III-Descending Pathways Flashcards Preview

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Flashcards in Exam III-Descending Pathways Deck (29):

What is the main function of the Lateral CorticoSpinal Tract?

ContraLateral Limb Control and Movement (discrete and SKILLED movement) muy importante!!


What is the main function of the Ventral/Anterior Cortico Spinal Tract?

Bilateral Axial Musculature


What is the INITIAL pathway (to the crossing) for the CorticoSpinal Tract?

P.M.C.->Corona Radiata->Internal Capsule->Cerebral Peduncles->Pyramidal Decussaiton


Which axons of the corticospinal tract cross at the pyramidal decussation? Which axons DONT cross?

The axons of the LATERAL corticospinal tract cross at the decussation, while the axons of the Ventral/Anterior CorticoSpinal Tract


What is the main purpose for the CorticoBulbar spinal tract? What C.N.'s does it feed into?

To provide motor innervation to the face and eyes, so III, IV, V, VI, VII, IX, X, XI, XII.


What is unique about the corticobulbar tract that is associated with VII?

The axons of the CorticoBulbar Tract that become fibers of VII DO NOT CROSS and they become BILATERAL. Where as all the other fibers of the CNs that the CorticoBulbar Tract feed into cross.


Where does the RubroSpinal Tract Originate? Do the axons cross?

The Red Nucleus in the Midbrain. YES they Cross


Where are the axons of the RubroSpinal Tract in relation to the Lateral CorticoSpinal Tract?

The axons of the Rubro are just anterior to the Lateral tract. This makes sense c/o their fxns


What is the main function of the RubroSpinal Tract? OWN THIS TRACT!

Skilled Dexterous Movements of the Upper Extremety :)


What are the two main tracts of the ReticuloSpinal Tract? Where do they arise?

The Pontine(Medial) ReticuloSpinal Tract arises in the PONS...GET IT? PONTINE/PONS :) The Medullary(Lateral) ReticuloSpinal Tract arises in the MEDULLA...GET IT?


Is the medullary reticulospinal tract crossed or uncrossed or both?

Both Crossed and Uncrossed


What is the main function of the Medullary ReticuloSpinal Tract? What does it inhibit? What does it facilitate?

M.F.F. Medullary Facilitates Flexors.......Inhibits lower extremity extensors, Facilitates lower extremity Flexors (F&F!!!)


Are the axons of the Pontine reticuloSpinal tract crossed or uncrossed or both?



What is the main function of the Pontine ReticuloSpinal Tract?

Pontine is the Punting Tract :) P.P.E.-Pontine Powers Extensors of the lower extremity


What are the two VestibuloSpinal Tracts?

Lateral VestibuloSpinal Tract and Medial VestibuloSpinal Tract


What is the ascending reflex we discussed for the vestibulospinal tract?

The MedialLongitudinalFasiculus...The VestibuloOcular Reflex


Where does the Lateral VestibuloSpinal Tract arise? hint hint, someones name

DEI-TER's Nucleus


What are the THREE (most confusing of all time) functions of the LateraVestibuloSpinal Tract?

1.Facilitate Extensors of Lower Extremeties (Pontine ReticuloSpinal Tract) 2. Facilitate Flexors of the Upper Extremeties 3. PRIMARY ANTIGRAVITY pathway


What are the Three somewhat confusing functions of the MedialVestibuloSpinalTract?

1. Facilitate Flexors of the UpperExtremities 2. Inhibit Upper Extremity Extensors 3.AntiGravity


What is the function of the TectoSpinalTract? Why does it get you in trouble with your nova?

It mediates movement of the head and neck in response to NOVEL STIMULI (girl in the red dress)


What does it mean that the spinal cord is "segmented"?

That upper motor neurons synapse with lower motor neurons at different levels of the spinal cord.


Are large muscles supplied by few or several ventral roots?

Large muscles (my biceps :)) are supplied by several ventral roots (c5-c6)


What is PARTIAL paralysis if only one or two ventral roots are damaged?



What are the two possible causes of paralysis of a muscle?

1. If ALL ventral roots supplying a muscle are damaged 2. If Upper Motor Neurons are damaged in a stroke


What are the two main Myotomes we don't want damaged?

1. Anything above C3 because C3,4,5 keep the DIAPHRAGM alive 2. s2,s3,s4 keep the poo and pee off the floor


Which skeletal motor neuron type is BIG and FAST?

ALPHA dog. Alpha motor neurons are BIG in diameter and carry info fast to our Skeletal Muscle Fibers


Which skeletal motor neuron type is small and slow?

gamma. Keep muscles toned and Ready to pounce!


Which autonomic muscle fibers are lightly myelinated and relivitely large and fast?

B, Pre-ganglionic fibers


Which autonomic muscle fibers are unmyelinated and are there for small and slow?

C, Post-ganglionic fibers