Nervous System Flashcards
Four Brain Regions
Cerebrum: frontal, parietal, temporal, occipital
Diencephalon-Thalmus, Hypothalmus and basal ganglia
Brainstem- Midbrain, Pons, Medulla
Cerebellum
Brain Tissue
Gray- formed by collection of erve cell bodies
White- myelin coated axons
Internal capsule- where all myeinated fibers from cerebral cortex converge and descend into brainstem
Diencephalon
Thalmus(sensory impulses relay to cerebral cortex) Hypothalmus( homeostasis- reg HR,BP, Temp also endocrine, emo behavior. Hormones excreted from hypothalmus directly affect pituitary) basal ganglia(affect movement)
Thalmus vs Internal Capsule
Thalmus bus stop for all sensroy impulses going into brain, Internal capsule bus stop for all sensory impules going out of brain
Consciousness
interaction between cerebral hemispheres, diencephalon, upper brainstem, RAS
Cerebellum
base of brain, coordinates movement, maintains upright position
Spinal Cord
C1-8 T1-12 L1-5 S1-5 C
Cauda Equina
Spinal cords ends at L1-2, then the lumbar and sacral roots fan out like horse tail
Lumbar puncture
done L3-4 or L4-5
CN 1-12
On old olympus towering tops a finn and german viewed some hopps
CN can be motor, sensory or both
Some say marry money but my brother says big breasts matter more
Nerve Roots
Ant root- motor/efferent
Post root- sensory/afferent
Upper motor neurons
cell bodies originate in brain and spinal cord. UA to leave CNS, must synapse with lower motor neurons, which carry message to muscle/rest of body
Lower motor neurons
cell bodies located in brain stem, but axons can leave CNS to synapse with muscles- These are cranial/spinal nerve
Motor: Corticospinal (pyramidal) tract
mediate voluntary movement by stim muscle action and inhibiting others. Carry impulses that inhibit muscle tone. Originates in motor cortex of brain. Motor fiber travels down lower medulla, cross to opposite side of medulla, cont down, syn with ant horn/immediate neurons.
Corticobulbar
tracts synapsing in brainstem with motor nuclei of CN
Motor: Basal Ganglia System
complex system includes motor pathway between cerebral cortex, basal ganglia, brainstem, spinal cord. Maintains muscle tone and control body movements
Motor: Cerebellar System
receives sensory/motor input and coordinates motor activity, maintains equilibrium, helps control posture.
Movement
Voluntary- Cortex
Automatic- basal ganglia
reflex sensory- sensory receptors.
Higher motor pathways
affect motor mvmt only through lower system- translates into sction in ant horn. Lesion in any areas- will affect mvmt or reflex activity
Upper vs Lower motor neuron damage
Upper- inc muscle tone/DTR
Lower- dec muscle tone/DTR
Damage to Basal Ganglia
inc muscle tone, diturbs posture/gait, bradykinesia, invol mvmt
Damage to Cerebellum
dec muscle tone, imp coordination/gait & equilibrium
Nystagmus, dysarthria, hypotonia and ataxia
Sensory Pathways
reflex activities, conscious sensation, body position, reg ANS(HR,BP,RR), relays impulses from skin/mucous membranes/ tendons/ viscera, reg sensation of pain/temp/position/touch.
Sensory: Spinothalmic Tract 1
from neuron to post horn, synapse with secondary neurons- cross to opposite side and travel up to thalmus (Pain, temp, crude touch-light touch not localized)
Sensory: Spinothalmic Tract 2
sensations of vibration/position/fine touch(with localization)- pass directly into post horn- travel up to medulla with secondary sensory neurons, cross to opposite side at medullary level and cont to thalmus.
Thalmic Level
Quality of sensation perceived, fine distinction not made
Sensory Cortex
Full perception, localization, high order discrimination made
Sensory Cortex Lesions
may not impair perception of pain/touch/ position but will impair finer discrimination.
Cannot appreciate size/shape/texture of object by feel.
Proprioception
sense of mvmt, body position independant of vision. Gained from input of sensory nerve terminals in muscles/tendons/joints/vestibuar apparatus
Loss of position sense- tabes dorsalis, MS, B12 def from post colum disease, PN form DM
Dermatome
band of skin innervated by sensory root of a single spinal nerve
Sensory level may be several segments below injury- reason unknown
DTR
tap on tendon, activates special sensory fibers, trigger sensory impulse to spinal cord via peripheral nerve synapses directly with ant horn innervating same muscle, crosses NM junction, muscle contracts, completes reflex arc
HH c/o
HA, dizzy, vertigo, weakness, numbness, abn/loss of sensation, LOC, syncope/near-syncope, Sz, tremors/invol mvmt
HA
Ask: severity, location, duration assoc Sx like visual, wkns, loss of sens. Affected by sneezing, coughing or suddent mvmt of head- which can inc ICP
SAH- worst HA of life
Meningitis- severe HA
Mass lesions/absess- dull HA in same location
Dizzy
what experienced, light headed/faint, room spining/rotating
Light-headedness in plapitations, near syncope from VV stim, low BP, febile, or others.
Vertigo- inner ear, brainstem tumor.
Elderly- meds may contribute
Assoc Sx- diplopia, dysarthria, ataxia- may be present in vertebrobasilar TIA or CVA
Weakness
Assoc with, gen/location, paralysis, onset, progression, mvmt affected?
TIA/CVA- wkns/paralysis
Focal wkns- ischemia, vasc, mass lesion CNS, PNS, MS DO, muscle diseases
Bilat prox wkns- myopathy
Myasthenia Gravis
wkns made worse by repeated effort and imp with rest
Loss of Sensation
numb, diff moving a limb, alter sens, tingling/pins-needles
Parasthesia
Limb goes to sleep= compresion of nerve, tingly. prickly, feeling of warmth, coolness or pressure.
If in hands and around mouth- hyperventilation
Dysesthesia
distorted sensation in repsonse to stim, may last longer than stimulus
Pain
May arise from neurologic causes but often reported with Sx of other body systems
Burning pain- painful sensory neuropathy
LOC/ fainting
Complete black out or hear voices.
Symptoms of feeling faint- light headed, weak, wo actual LOC- near/presyncopal
Anyone witness- Sz mvmt, onset/offset sudden/slow
Syncope
sudden temp LOC and postural tone- dec blood flow to brain
Cardiac- arrythmias cause- more common in older pt, sudden onset/offset. AS, HOCM, MI, Massive PE
Other causes of syncope: Hypocapnea d/t hyperventilation, hypoglycemia, hysterical fainting.
Unlike Sz- no incontinence, tonic-clonic mvmt, postictal state but may have bitten tongue or bruised limbs.
Vasovagal
young people with stress- warning symptoms- flushed, warmth, N- slow onset, slow offset
Seizures
Paroxysmal DO sudden excessive electrical DC in cerebral cortex or underlying structure. May or may not LOC. Any abn feelings, thought process, sensation, smells, abn mvmt.
Tremors
unable to controll trembling/shaking/body mvmt.
RLS
develops at rest, accompanied by urge to move, relief with walking. Usually occurs at night. CNS iron/dopamine def, or dysmetabolism. Chronic ext tissue pathology/inflammation
Tx: daily exercise, adequate sleep, Dopaminergic meds (Requip,Mirapex), Correction of Fe def.
Health Promotion
Stroke/TIA prevention
Reduced periphearl neuropathy
Three D’s
Stroke stats
Ischemia 80-85%
Hemmorhage 15-20%
ICH 10-15%
SAH 5%
TIA
sudden focal neuro deficit lasts less than 24 hours. Precursor to stroke, 3 months after TIA, 15% progrss to CVA esp if RF present.
Stroke warning signs
sudden numbness, wkns, confusion, aphasia/dysathria, understanding, walking, dizzy, loss of balance/coordination, trouble seeing in 1 or 2 eyes, severe HA