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Corticospinal & Motor
For bootcamp quiz 1
26
Biology
Post-Graduate
01/21/2018

Additional Biology Flashcards

 


 

Cards

Term
Where is the intermediolateral column/horn in the spinal cord and what does it hold?
Definition

Thoracic level only

holds preganglionic autonomic fibers

Term
What part of the cord is most susceptible to ischemia?
Definition
T4-T8
Term
___ provides the major blood supply to the lumbosacral cord
Definition
Radicular artery of Adamkiewicz
Term

Decorticate posturing

- What you see

- Motor GSC score

- Cause

Definition

- Upper extremity flexion to noxious stimuli

- lesion to or above the rubrospinal tract (lesion above the midbrain)

- motor GSC score of 3

Term

Decerebrate posturing

- What you see

- motor GSC

- cause

Definition

- Extension of upper extremities to noxious stimuli

- motor GCS 2

- A lesion below the red nucleus that impairs the corticospinal, corticobulbar, or reticulospinal tracts

Caused by extensor innervation of the pontine reticulospinal and vestibulospinal tracts

Term
Pathway of the corticospinal tract (8)
Definition
  • Primary motor cortex in the precentral gyrus (Brodmann area 4) and premotor cortex (area 6) and supplementary motor area (area 6) and postcentral gyrus (parietal) (areas 3,1,2), and parietal association cortex (areas 5 and 7) – includes some sensory
  • Homunculus: face and arm laterally, leg is medial cortex
  •   -> corona radiata -> posterior limb of internal capsule (leg is lateral, arm is middle, face is medial) -> cerebral peduncle -> Basis pontis ->85% decussate in the lower lateral medulla -> lateral CS in the posterior lateral column, anterior CS in the anterior

 

Term

Corticospinal tract 

- function

- origin

- decussation

- localization in cord

- termination

Definition

DESCENDING PATHWAYS

Name

Origin

Pathway

Decussation

Localization cord

Termination

Somatotopic organization

Function

Corticospinal

Brodmann 4, 6, 1, 2, 3, 5, 7/

Precentral gyrus

Postcentral gyrus

Paracentral gyrus

Precuneus/

Primary motor

Premotor

Supplementary motor

Primary sensory

Parietal association

Corona radiate

Posterior limb internal capsule

Midbrain: Cerebral peduncle

Pons: Basis pontis

Medulla: Pyramid

Lower medulla/

Cervicomedullary junction

Lateral CS: Posterior lateral column

Anterior CS: Anterior column

AH

Cortex:

Leg-Medial

Arm-Lateral

Face-Lateral

 

IC, brainstem, spinal cord:

Leg: Lateral

Arm: Medial

Voluntary motor

   

 

             
Term

Rubrospinal tract

- function

- origin

- decussation

- localization in cord

- termination

Definition

DESCENDING PATHWAYS

Name

Origin

Pathway

Decussation

Localization cord

Termination

Somatotopic organization

Function

   

Rubrospinal

Red nucleus (Midbrain)

NA

Ventral tegmental decussation

-Lateral column

C

NA

Flexion arms

               

 

Term

Vestibulospinal tract

- function

- origin

- decussation

- localization in cord

- termination

Definition

DESCENDING PATHWAYS

Name

Origin

Pathway

Decussation

Localization cord

Termination

Somatotopic organization

Function

 
 

Vestibulospinal

-Lateral

-Medial

-Lateral: Superior + lateral vest nuclei

-Medial: Inferior + medial vest nuclei

NA

No

-Lateral VS: Anterolateral

 

-Medial VS: Medial

-Lateral VS: Entire cord

 

-Medial VS: C + upper T cord

NA

-Lateral: Balance

 

-Medial: Head + neck position

               

 

Term

Reticulospinal tract

- function

- origin

- decussation

- localization in cord

- termination

Definition

DESCENDING PATHWAYS

Name

Origin

Pathway

Decussation

Localization cord

Termination

Somatotopic organization

Function

 
 

Reticulospinal

-Pontine

-Medullary

Pontine and medullary reticular formation

NA

No

Anteromedial

Entire cord

NA

Automatic posture + gait

Term
What does dantrolene do?
Definition
(calcium channel blocker in the sarcoplasmic reticulum (at the ryanodine receptor))
Term
What is central cord disease?
Definition

congenital myopathy with a mutation in the Ryanodine receptor which predisposes to malignant hyperthermia (which you treat with dantrolene)

Term

Anterior horn motor neurons are in lamina ___ and contain ___ and ___ cells

- What do these cells do?

Definition

Lamina 9

o   Contains alpha and gamma fibers

§  Alpha goes to extrafusal fibers (most muscle fibers)

 

§  Gamma motor neurons go to intrafusal fibers in the muscle spindle

Term
In what spinal levels are sympathetic neurons found?
Definition

T1-L2

S2-S4

Term

Stiff Person Syndrome

- Cause

- Result

Definition

Cause: GAD65 antibodies (GAD 65 converts glutamate to GABA)

Result: Spasticity

Term

GAD65 has a cofactor of ___

- What does a deficiency of this cause in neonates

Definition

Cofactor of Vit B6

Deficiency causes seizures in neonates

Term
Destruction of what in the spinal cord causes clonus?
Definition

-          Destruction of descending inhibitory alpha motor neurons

o   A sudden stretch activates muscle spindles, resulting in the stretch reflex.

o   Tension produced by the muscle contraction activates the golgi tendon organs, which in turn activate an inverse stretch reflex, relaxing the muscle

§  Golgi tendon reflex aka Inverse stretch reflex aka inverse myotactic reflex: skeletal muscle contraction causes the antagonist muscle to simultaneously lengthen and relax

 

o   If the stretch is sustained, the muscle spindles activate again, causing a cycle of alternating contractions and relaxations.

Term
What chemical can cause a secondary vitamin B12 deficiency?
Definition
Nitrous oxide
Term
How can denture cream cause myelopathy?
Definition
A lot of zinc in denture cream. Zinc competes with copper for absorption in your gut (excess zinc intake can cause a secondary copper deficiency causing myelopathy). 
Term

Hereditary Spastic Paraparesis (HSP)

- Genetics

- Abnormal protein

- Result

Definition

- Multiple potential genes involved but most common is AD in SPG4 gene on chromosome 22

- Spastin protein, codes for microtubules

- Spasticity

Term
Name 6 potential medications for spasticity
Definition

Baclofen

Diazepam

Tizanidine

Botox

Dentrolene

Cyclobenzaprine

 

Term
Describe the MOA of baclofen
Definition
activates GABA-B-> causing K channel to hyperpolarize cell in order to block excitatory neurotransmitters
Term
Describe the MOA of diazepam
Definition
activates GABA-A-> causing chloride influx with hyperpolarization to block excitatory neurotransmitters
Term
Describe the MOA of tizanidine
Definition
agonist at a2-adrenergic receptor to increase presynaptic inhibition of motor neurons by causing negative feedback, blocks norepinephrine release
Term
Describe the MOA of botox
Definition
works at the neuromuscular junction SNARE complex to prevent presynaptic vesicle release of acetylcholine
Term
Describe the MOA of cyclobenzaprine (flexeril)
Definition
acts on the locus ceruleus where it inhibits norepinephrine release, also inhibits 5H-2a serotonin
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