Neurology Flashcards
What is the difference between an upper and a lower motor neuron?
Upper motor neurons represent central nervous system motor neurons (spinal cord and higher) while lower motor neurons represent the peripheral nerves outside the spinal cord and the muscle they innervate
What is grey matter and what does it do?
Grey matter (cerebral cortex) is the portion of the cerebrum in which all the meaningful things in life are processed. It is capable of “original thought” and it contains lots of nuclei of neural cells in order to create these important functions.
Grey matter is located above white matter
Why is white matter white?
Because it is mielenated meaning it can transmit impulses fast from grey matter tissue.
It is located beneath the cerebral cortex
What is the purpose of the basal ganglia? Why are they susceptible to hypoxic injury?
Basal ganglia provide fluidity of movement, and breakdown of these is what leads to conditions like parkinson’s.
They are susceptible to hypoxic injury because they are at the distal ends of the blood vessels.
What is the purpose of the thalamus?
Deep subcorticol grey matter than provide a relay point between cerebral cortex and the brainstem (the AV node of the brain).
Susceptible to global hypoxic injury because it is at the distal end of the brain perfusion
Why is the cortex susceptible to hypoxia?
High metabolic activity with no backup energy source
What it the purpose of the frontal lobes?
Appropriateness, executive functions,
Can function without one frontal lobe!
What portion of vision does the right occipital lobe control?
Left half of left eye and left half of right eye
What is the function of the temporal lobe?
Memory
What is the function of the parietal lobe?
Sensation, movement, Speech (understanding and producing)
Most important lobe
What side of the parietal lobe does speech understanding and production occur?
99% of people left side parietal lobe
What part of the cortex is upper body, legs and face?
Face is lateral cortex, upper body/hand is middle and medial is foot/leg
What is the internal capsule?
Bundle of fibers that come from cortex and go down to the spinal cord
Why does the right side of brain control left side of body for sensation and movement?
Because the internal capsule crosses over just above the midbrain meaning homunculus functions are for the contralateral side
What is the function of the brainstem?
1) Relays everything
2) Unconscious part of body (breathing while sleeping)
3) Houses 10 of 12 cranial nerves
Which cranial nerves cross over?
7 and 8
What is function of respiratory center?
Senses CO2 and triggers unconscious breathing
What does the pupillary constriction test tell you about brainstem?
CN II senses the light, CN III constricts the pupil and you know that the majority of the brainstem is intact
How do we test the brainstem reflexes in an intubated patient?
Pupil constriction reflex (II, III) Cornea reflex (V, VII) Cough Gag (IX, X) Respiratory effort (Mode of ventilation, effort) (Respiratory center)
What is the purpose of RAS? Where is it located?
RAS is located in the midbrain, it tells the thalamus to wake up repeatedly (thalamus tells the cortex to wake up) and keep us conscious
Why do you get blown pupil on same side as pathology, while the deficits are detected on the other side during uncul herniation?
Is this an early or late sign?
Uncus pushing down on 3rd cranial nerve in the midbrain (which doens’t cross over) while the same compression of the midbrain affects motor neurons that cross over just below the midbrain
Early sign because as the herniation progresses, both unci push down on both sides of the midbrain
What is the uncus?
Bottom floor of the temporal lobe
What is the risk of sedating an infratentorial pathology?
Have to wait for neuro exam and during that delay more brain tissue is lost. DO NOT sedate infratentorial herniation
WHY do you put an infratentorial herniation patient on pressure support?
Because pressure support allows you to monitor their herniation syndrome and the respiratory center is impacted early in the course of the disease through tonsilar pressure