nsl4

Studylist 3

Test 2 included the basic anatomy of the dorsal column pathway, but we had not yet covered disorders affecting the dorsal column pathway, so they will be on this test:
pathological changes in dorsal column pathway
        degeneration of dorsal column neurons, e.g. in some cases of MS, leading to loss of dorsal column sensations
            astereognosis
        tabes dorsalis and other conditions that can damage the dorsal columns (MS, peripheral neuropathy, B12 deficiency)
        sensory ataxia, Romberg's sign

route taken by the ascending spinothalamic pathways or tracts (pain, temperature, and gross touch)
        release of bradykinin, prostaglandins, histamine when tissue is injured
        release of neurotransmitter "substance P" by first neuron in pathway
        substantia gelatinosa
        second neuron crosses in spinal cord
        lateral white matter of cord
        VP thalamus
        somatosensory cortex of parietal lobe

"gate control" for pain in substantia gelatinosa portion of dorsal horns and what "closes the gate"
descending pain suppression pathway from midbrain periaqueductal gray
mislocalizing the source of ANS pains ("referred pain")

disorders related to spinothalamic pathway (see study guide)
herpes zoster (shingles)
syringomyelia

descending pathways or tracts of the spinal cord

lower (alpha) motor neurons - "final common path"
    what are they
    motor units (motor neuron and its extrafusal muscle fibers)
    what are the symptoms seen if LMNs are damaged
        loss of voluntary and reflexive movements of the involved muscle fibers
        flaccid paralysis
       denervation atrophy of the involved muscle fibers
            fasciculations following denervation
    example of a disorder affecting LMNs
        poliomyelitis

upper motor neurons
    what are they
    what are the symptoms if UMNs are damaged
    example of disorder affecting UMN

corticospinal tract or pathway (functions and path it takes through brain and cord) (aka pyramidal tract)
    cortex
    internal capsule
    pyramids of medulla
    crosses at medulla-cord junction "decussation of the pyramids"
    lateral corticospinal tract in lateral white matter of cord
symptoms of corticospinal damage (what would you be unable to do, what aspects of your behavior would change)

extrapyramidal pathways
    rubrospinal - to flexors
    vestibulospinal - to extensors
    reticulospinal - modulate reflexes and muscle tone
    tectospinal - reflexive movements to visual stimuli
other parts of motor system influencing these descending pathways : basal ganglia and cerebellum
abnormal postures after UMN injury (decorticate and decerebrate)

spinal reflexes
    monosynaptic stretch reflex - neurons involved?
        stretch (muscle spindle) receptors containing intrafusal muscle fibers
        knee jerk (a "deep tendon" reflex)
        functions of the stretch reflex
    flexor or withdrawal reflex of hand
    withdrawal reflex and crossed extensor reflex of leg
    UMN modulation of spinal reflexes - can increase or decrease how easily stretch reflex is triggered

changes in spinal reflexes after UMN damage
    positive Babinski reflex
    hyperactive stretch reflex
    clonus
spastic paralysis

gamma motor neurons (what they are, what they synapse on)
    gamma motor neuron modulation of stretch reflex
    UMN influence on gamma motorneurons
    How this relates to the symptoms of UMN damage

disorder affecting both LMNs and UMNs:
amyotrophic lateral sclerosis (see study guide)

anatomy of spinal cord cross sections - how the changes in amount of white matter and gray matter relate to the paths we've discussed

autonomic nervous system organization
responses triggered by each division of the ANS
anatomical characteristics of each divsion of the ANS (thoracolumbar vs craniosacral)
how an outgoing autonomic message to body differs (anatomically) from an outgoing motor message
    preganglionic neurons
    autonomic ganglia
    postganglinic neurons
    difference in pre and postganglionic neurons in the sympathetic vs the parasympathetic divisions
functional and chemical differences between the sympathetic and parasympathetic divisions
    use of these chemical differences in drug therapies
ANS dysfunctions
    Reynaud's Syndrome
    autonomic dysreflexia
how spinal injuries affect autonomic function
spinal shock
various events or forces on the spinal cord that can result in damage
how level relates to possible disabilities (paraplegia vs quadriplegia)

how a partial spinal cord injury would affect ascending and descending pathways (What sensations from what part of body would be lost, what motor functions from what part of the body would be affected)

cerebellum
    basic anatomy
        cerebellar hemispheres covered with very convoluted cerebellar cortex
        vermis
        cerebellar peduncles
        anterior, posterior and flocculonodular lobes
    Functional regions and what kind of input each processes to aid in the control of movement
        archicerebellum (flocculonodular lobe)
        paleocerebellum (vermis area)
        neocerbellum (hemispheres)
functions of the cerebellum
symptoms of cerebellar damage
cerebellar dysfunctions
    drug-induced (e.g. alcohol)
    genetically based abnormalities in cerebellar function
    cerebellar lesion (damage)
    medulloblastoma