BBB, Neurotransmitters, Dermatomes B&B Flashcards
what are the 4 major circumventricular organs (CVOs)?
- area postrema
- OVLT (organum vasculosum of the lamina terminalis)
- subfornical organ (SFO)
- median eminence of the hypothalamus
where is the area postrema found, and what is this area known for?
caudal end of the 4th ventricle in the medulla
circumventricular organ (CVO) - “chemoreceptor trigger zone” (chemo agents affect this area, cause signaling to the vomiting center in the medulla)
where is the OVLT found, and what kind of neurons does it contain?
OVLT (organum vasculosum of the lamina terminalis): circumventricular organ (CVO) found in anterior wall of third ventricle
contains osmosensory neurons
where is the subfornical organ (SFO) found?
circumventricular organ (CVO, no BBB)
found in anterior wall of third ventricle
what is the main source of norepinephrine in the brain?
locus ceruleus in the posterior pons, near the 4th ventricle
where are the 2 locations within the brain in which dopamine is synthesized?
- ventral tegmentum
- substantia nigra
both in midbrain
how do dopamine levels differ in schizophrenia vs Parkinson’s?
schizophrenia - increased dopamine
Parkinson’s - decreased dopamine
where is GABA synthesized in the brain? which enzyme is required? which vitamin is required as a cofactor for this reaction?
(gamma-aminobutyric acid)
synthesized in nucleus accumbens (pleasure/reward center) via glutamate decarboxylase (requires B6!)
activation of GABA receptors allow which ion to flow into the cell? where are GABA(A) vs GABA(B) vs GABA(C) receptors found?
GABA receptor activation —> chloride influx
GABA(A/B) found in brain, GABA(C) found in retina
where is serotonin synthesized in the brain?
raphe nucleus (pons)
what is the classic triad of serotonin syndrome?
(aka too much serotonin)
- mental status change
- autonomic hyperactivity (tachycardia, hyperthermia, diaphoresis)
- neuromuscular abnormalities (tremor, clonus, hyperreflexia, bilateral Babinski sign)
how can neuroleptic malignant syndrome (NMS) be differentiated from serotonin syndrome?
both —> muscle rigidity, fever, change in mental status, autonomic instability
NMS (rxn to neuroleptic medications) —> “lead pipe” rigidity, high creatine kinase (CK) levels
serotonin syndrome —> clonus (rhythmic muscle spasms)
Pt presents to the ED with fever, confusion, and rigid muscles. PMH is significant for depression. What drug will you administer to reverse these symptoms?
patient is experiencing serotonin syndrome from anti-depressants
treat with cyproheptadine (5-HT antagonist, also anti-histamine)
where is acetylcholine synthesized in the brain?
basal nucleus of Meynert (subcortex)
the symptoms of Huntington’s are due to neuronal death from _____ toxicity
glutamate toxicity - binds NMDA (N-methyl-D-aspartate) receptor, excessive calcium influx
glutamate = major excitatory neurotransmitter
to which receptor does phencyclidine (PCP, “angel dust”) bind?
antagonist of NMDA (N-methyl-D-aspartate) receptor for glutamate (major excitatory NT)
—> violent behavior, hallucinations, ataxia, nystagmus (uncontrolled, repetitive eye movements), HTN, tachycardia, diaphoresis, seizures, coma
damage to spinal nerve T10 causes referred pain to where? where does this pain actually originate?
T10 = umbilicus, referred pain for appendicitis
common first symptom of appendicitis is pain in the belly button
which spinal nerves are being tested by the following reflexes?
a. biceps
b. triceps
c. patella
d. achilles
a. biceps - C5
b. triceps - C7
c. patella - L4
d. achilles - S1
how can nerve root syndromes originating in L5 vs S1 be differentiated (2 most common)?
L5 (L4/L5 disc) —> back pain down lateral leg, foot strength reduced, reflexes normal
S1 (L5/S1 disc) —> pain down back of leg, weak plantar flexion, ankle reflex lost
what is the Babinski sign
aka plantar reflex - rubbing bottom of foot should cause downward pointing toes (plantar flexion)
“upward going toes” (dorsiflexion) is a positive Babinski sign, indicates UMN damage (but normal in infants, due to incomplete myelination)
what are the 6 primitive reflexes (present in babies)?
- moro reflex: baby dropped slightly on back will spread arms, then retract them, then cry
- rooting: baby turns cheek towards side of stroke
- sucking: baby sucks anything touching roof of mouth
- palmar: baby will grasp anything stroking palm
- plantar: Babinski reflex, “upward going toes”
- galant: baby swings legs side to side if stroked on their back
how does CSF sampling differ between bacterial and viral meningitis?
bacterial: high protein, low glucose, HIGH WBC
viral: mildly high protein, normal glucose, normal/mildly high WBC (lymphocytes)
what are the 3 components of the BBB?
- endothelial tight junctions
- perivascular pericytes
- astrocyte foot processes
