Ridiculously Simple Flashcards
Brain and spinal cord
Central nervous system
Peripheral nerves
Peripheral nervous system
frontal lobes, temporal lobes, parietal lobes, and occipital lobes
Cerebral hemisphere
thalamus and basal ganglia
cortical structures
midbrain, pons, medulla
brain stem
cluster of neuron cell bodies
gray matter
myelinated axon pathways
white matter
Makes myelin in the periphery
schwann cells
Makes myelin in the central nervous system
oligodendrocytes
Transmit sensory information from the head to the brain
cranial nerves
Transmit sensory information from the rest of the body to the brain
peripheral nerves
Pathway that projects from cortex to spinal cord
upper motor neurons
Pathway that projects from spinal cord to muscle
lower motor neurons
main motor pathway
corticospinal tract
Synapse on the anterior horn cells in the anterior spinal cord
upper motor neurons
Synapse on the muscle
lower motor neurons
What side of the body does the right motor cortex control?
Left side of body
What side of the body does the left motor cortex control?
Right side of body
Flaccid paralysis, diminished/absent reflexes, fasciculations, and muscle atrophy over time
Sx of lower motor neuron lesion
Spastic paralysis, increased reflexes, clonus (esp. unilateral) and disinhibition of primitive reflexes (e.g. Babinskis)
Sx of upper motor neuron lesion
If you stroke the bottom of the foot and the big toes curls up instead of down
Positive Babinkski’s sign in adults
repetitive, rhythmic contraction of a muscle when it is stretched, commonly seen in the ankle
Clonus
Where will the motor deficit be if the lesion is above the decussation of the corticospinal tract?
Contralateral (opposite) side
Where will the motor deficit be if the lesion is below the decussation of the corticospinal tract?
Ipsilateral (same) side
Two main sensory pathways
posterior columns (or dorsal columns) and spinothalmic tracts (or anterolateral tracts)
Transmits discrimination touch, vibration, and proprioception
Posterior column
Pain and temperature sensation
spinothalmic tract
When so the spinothalmic tracts cross in the spinal cord?
Immediately
When do the posterior columns cross?
At the medulla and continue as medial lemnisci
isolated motor or sensory deficits typically occur with small, isolated lesions in very specific places
CNS
isolated motor or sensory deficits include root lesions or disease affecting the motor or sensory systems specifically
PNS
Doesn’t project into the brainstem but into olfactory cortex
Olfactory nerve- CN I
Projects to the midbrain for afferent limb for pupillary light reflex and visual pathway projects to lateral genuculate nucleus of the thalamus
Optic nerve- CN II
Will impair motor and sensory function on the opposite side of the body and cranial nerve function on the same same of the body
brainstem lesion ABOVE the decussation in the medulla
Lesion of CN I (olfactory nerve) will lead to…
anosmia-loss of smell
