Neurophysiology, Medbullets Flashcards
Support cells: GFAP (+)
Astrocytes
Support cells: Become rod cells in neurosyphilis
Microglial cells
Seen in perivascular cuffing during viral encephalitis
Microglial cells
The only CNS/PNS support cell to originate from mesoderm
Microglial cell
Support cells: Fried egg appearance on H&E
Oligodendrocytes
Each oligodendrocyte myelinated a maximum of how many axons
30
Oligodendrocytes are destroyed in what disease
MS
Each Schwann cell myelinates how many axons
1
Schwann cells are derived from
Neural crest cells
Schwann cells are destroyed in what disease
Guillan-Barre syndrome
Intrafusal vs extrafusal: Muscle spindle
Extrafusal
Muscle spindle neuronal circuit (4)
1) Muscle stretch stimulates 1a afferent neurons 2) 1a afferent neuron enter the dorsal horn 3) Stimulation of a-motor neuron propagates a reflex arc 4) Muscle contraction
Muscle length vs tension: Muscle spindle
Muscle length
Muscle length vs tension: Golgi tendon
Muscle tension
Intrafusal vs extrafusal: Golgi tendon
Intrafusal
Parallel vs in series with muscle: Muscle spindle
Parallel
Parallel vs in series with muscle: Golgi tendon
In series
Golgi tendon neuronal circuit
1) Inc muscle tension stimulates 1b afferent neurons 2) 1b afferent neurons inhibit a-motor neurons 3) Muscle relaxation
Ach is increased in
Parkinson’s
GABA is synthesised in
Nucleus accumbens
NTs decreased in depression (2)
1) GABA 2) Serotonin
NE is synthesised in
Locus ceruleus
NE is increased in
Anxiety
Effect of infarction on tight junctions
Destruction resulting in vasogenic edema
Water-soluble vs lipid-soluble molecules: Cross the blood-brain barrier
Lipid-soluble (nonpolar)
Transport of glucose and amino acids through BBB
Carrier-mediated
CSF: Normal amount of lymphocytes/mononuclear cells
0-4 per mm3
CSF: Presence of neutrophils may be normal
F, always abnormal
CSF: Conditions of increased protein
1) CNS tumors 2) GBS
Compared to serum, CSF has less
1) Protein 2) pH 3) K, Ca, HCO3 4) Glucose
Compared to serum, CSF has more
Cl and Mg
Choroid plexus are found in
Lateral, 3rd, and 4th ventricles
Entire volume of CSF is recycled ___ times per 24 hours
2-3
Mechanisms of communicating hydrocephalus (2)
1) Decreased resorption as in scarring following meningitis 2) Increased production as in choroid plexus tumour
Most common site of stenosis along the ventricular system
1) Foramen of Monro 2) Cerebral aqueduct of Sylvius
Mechanisms of hydrocephalus with normal pressure
1) Chronic dilation 2) Distortion of corona radiata
Mechanism of hydrocephalus ex vacuo
Small brain as in Alzheimer’s, advanced HIV, and trauma
T/F More sensitive areas receive a greater representation in the sensory homunculus
T
T/F More precise muscles receive a greater representation in the motor homunculus
T
Homunculus
Awake and alert
Beta
Awake and eyes closed
Alpha
Stage 1 (Light sleep)
Theta
Stage 2 (Deeper sleep)
Sleep spindles and K complexes
Stage 3 Deepest nREM, sleepwalking, night terrors, bedwetting
Delta
REM (dreaming)
Beta
Substances that reduce REM and delta sleep
1) Alcohol
2) Benzodiazepines
3) Barbiturates
Mechanism by which alcohol, benzodiazepines and barbiturates reduce REM and delta sleep
GABA agonists
EOM during REM is due to activity of
Paramedian pontine reticular formation
NT that reduce REM sleep
NE
REM occurs every ___ min
90
Excessive daytime sleepiness
Narcolepsy
Narcolepsy: Hallucinations just before sleep
Hypnagogic
Narcolepsy: Hallucinations just before awakening
Hypnopompic
