H&P Neurology Overview Flashcards
Diencephalon
Basal Ganglia: movement
Thalamus: process sensory input and relays to cerebral cortex
Hypothalamus: homeostasis
What system is repsonsible for arousal?
reticular activating system
3 parts of the brainstem
midbrain
pons
medulla
What level is an LP performed at?
L3-L5
anterior vs posterior nerve roots
anterior: efferent fibers sending motor signals
posterior: afferent fibers receiving sensory signals from periphery
Motor pathways: Pyramidal vs. Extrapyramidal Functions
Pyramidal: Corticospinal AKA Pyramidal Tracts
- mediate voluntary movement and integrate skill, complicated or delicate movements by stimulating selected muscular actions while inhibiting others
- carry imulses that inhibit muscle tone
- originate in the motor cortex of the bain, travel down the medulla (anatomical pyramid)
- at the pyramid, most fibers cross to the contralateral side of the medulla
Extrapyramidal
- Basal Ganglia System:
- includes pathways between cerebral cortex, basal ganglia, brianstem and spinal cord
- helps maintain muscle tone and controls gross body movements liek walking
- Cerebellar System
- receives sensory and motor input and coordinates motor activity, maintains equilibrium and helps to control posture
UMN vs. LMN
UMN
- in cerebral cortex
- synapse in brainstem for cranial nerves
- synapse in spinal cord for peipheral nerves
LMN
- have cell bodies in the anterior horn of cod
- transmit impulses through the anterior roots and spinal nerves into the peripheral nerves, **terminate at the neuromuscular junction **
Corticospinal tract lesions
STORM Baby
UMN
- Strength lowers
- Tone increases
- Others - superficial reflexes absent, clonus
- Reflexes (DTR) amplified
- Muscle Mass - slight loss only
- Babinski - positive (toe up)
LMN (everything lowers)
- Strength lowers
- Tone decreases
- Others- fasciculations, fibrillations
- Reflexes (DTR) - decreased
- Muscle Mass - atrophy/decreases
- Babinski- negative (toe down)
If damaged or destroyed, functions are lost below the level of injury
When UMN systems are damaged above the crossover in the medulla, motor impairment develops on the opposite side as the injury.
If damage occurs below the crossover, motor impairment is seen on the ipsilateral side as the injury.
The affected limb becomes weak or paralyzed, and skilled, complicated/delicate movements are affected more than gross movements
Extrapyramidal Lesions
Basal Ganglia
- diseases cause non-paralyzing disability
- increased muscle tone, posture and gait disturbances (bradykinesia) and involuntary movements like tremor
Cerebellar system
- receives sensory and motor input and coordinates motor activity, maintains equilibrium and helps control posture
- damage impairs coordination, gait and equilibrium and causes decreased muscle tone
- impaired by muscle tone
Sensory Function
Spinothalamic and Posterior Columns
Spinothalamic columns
- dorsal root–> posterior horn –> synapses on secondary neuron –> crosses over and travels anteriorly –> spinothalamic tract –> ascends to thalalmus
- carries crude touch, pain, and temperature
Posterior columns
- dorsal root –> directly to posterior column (white matter posterior to posterior horn) –> ascends to medulla –> crosses over and synapses on secondary neuron –> ascends to thalamus
- carries position, vibration, and fine, discriminating touch
General quality of sensation is perceived at the thalamic level
A third group of sensory neurons carry stimuli from thalamus to sensory cortex of the brain where they are localized and higher order discriminations are made
Sensory Lesions
Check dermatones for sensory impairment (band of skin innervated by the sensory root of a single peripheral spinal nerve)
Sensory cortex lesions - impairs finer discrimination (but things like pain are intact)
Posterior column lesion - impairs position and vibration sense
Loss of sensation in legs with paralysis and hyperactive reflexes indicates cord transection
Neurologic Health Promotion
Cerebrovascular disease is 3rd leading cause of death and number 1 cause of disability
Aggressively manage risk factors:
- HTN
- dyslipidemia
- DM
- obesity
- A. fib
- smoking
- sedentary lifestyle
- alcohol use
TIA
- stroke symptoms that resolve within 24hrs (generally last 1-2hrs)
- highest risk of progressing to stroke is from 1-3 months
- pts who have vascular disease (cardiac or peripheral) are at greatest risk
Cranial Nerves
- CN I - Olfactory
- CN II - Optic
- CN III - Ophthalmic
- CN IV - Trochlear
- CN V - Trigeminal
- CN VI - Abducens
- CN VII - Facial
- CN VIII - Vestibulocochlear
- CN IX - Glossopharyngeal
- CN X - Vagus
- CN XI - Spinal Accessory
- CN XII - Hypoglossal
