March 28 - Neuro Flashcards
Pre and postcentral gyri
Pre: motor cortex, part of frontal lobe
Post: sensory cortex, part of parietal lobe
Effect of botulinum toxin vs organophosphates vs tetrodotoxin
Botulinum toxin: Blockade at both nicotinic and muscarinic receptors
Organophosphates; AChEIs. Depolarizing NMJ blockade leading to weakness and paralysis. CNS symptoms (lethargy and seizures). Agonize muscarinic receptors by increasing ACh.
Tetrodotoxin: found in puffer fish. Inhibit Na+ channels causing paralysis
MSUD: enzyme defect
branched chain alpha keto acid dehdrogenase
POMC
Precursor molecule to endorphins, ACTH, and MSH
Cingulate herniation
Also called subfalcine herniation. Cingulate gyrus herniates beneath faux cerebri. Compresses ACA leading to gait problems and coma
Uncal herniation
Uncus herniates through tentorium cerebelli. Compresses midbrin - CNIII – leading to oculomotor palsy and dilated pupil. Can also cause duret hemorrhage and occipital lobe infarction due to PCA compression
Tonsilar herniation
Herniation of cerebellar tonsils thorugh forament magnum. Can compress the midbrain cardiorespiratory center leading to death
Pramipexole
Dopamine agonist used to treat PD
Direct pathway in basal ganglia
Goal is to stimulate movement
Cortex activates striatum. Striatum inhibits GPi and pars reticulata resulting in disinhibition of the thalamus
Amplified by cortex stimulating substantia niagra pars compacta which stimulates striatum via D1 receptors
Indirect pathway in basal ganlgia
Goal is to inhibit movement
Cortex actiavtes striatum. Sriatum inhibits GPe, which normally inhibits the subthalamic nucleus. Subthalamic nucleus freed to stimulate GPi resulting in increased inhibition of the thalamus.
Effect decreased by cortex stimulating substantia niagra which inhibits the striatum via D2 receptors
Basal ganglia: ipsilateral/contralateral
Communicate with ipsilateral motor cortex so affect contralateral body.
COMT inhibitors
Entacapone and tolcapone. Entacopone prevents peripheral breakdown of L-dopa, tolcapone stimualtes both peripheral and central breakdown. Hepatotoxicity
Selegiline
MAO-b inhibitor - prevents breakdown of L-dopa centrally, increasing DA. Risk of serotonin syndrome when given with SSRI. Can cause tyramine reaction just like MAO-a inhibitors for depression
Benztropine
centrally acting muscarinic antagonist used to treat PD
Blood:gas partition coefficient
Used to describe the blood solubility of inhaled anesthetics. Inhaled anesthetics only have effect when NOT dissolved in blood and have a partial pressure in the blood. Thus, higher blood solubility means the drug takes LONGER to take effect and has slower offset.
Oil:gas partiton coefficient
Describes lipid affinity of drug and correlates with potency (increased lipid solubility=increased potency). Inversely related to the MAC which is the minimum albeolar concentration that will prevent movement in 50%
Halothane toxicity
Malignant hyperthermia, hepatotoxicity
Enflurate toxicity
Seizure
Global cerebral ischemia
Caused be decreased cerebral blood flow. Most vulnerable areas are pyramidal cells of hippocampus and cortex and purkinje cells of cerebellum. Hippocampus is first area to be damaged
Cerebral amyloid angiopathy
Beta amyloid deposits in walls of small to medium cerebral arteries. Causes walls to be weak and predisposed to rupture, resulting in recurrent lobar hemorrhages.
Heat sensitivity in MS
Heat such as from hot shower or strenuous exercise decreases axonal transmission resulting in worsened neuro symptoms and increased fatigue
Optic neuritis
Visual disturbance + eye pain
Seen in MS
Iliohypogastric nerve
Innervates anterolateral abdominal wall muscles. Can be damaged in appendectomy resulting in decreased sensation at suprapubic region
Chemoreceptor trigger zone
Area postrema on posterior surface of MEDULLA
HIV-associated dementia
Seen iwth CD4 less than 200. Subcortical dementia resulting in problems wth working memory, attention, executive function.
HIV infected monocytes cross BBB. Activated macropahges and microglial cells form microglial nodules around areas of necoris.
Facial nerve parasympathetics
Innervate lacrimal, submandibular, and sublingual glands
Benzos and barbs
Benzos increase Cl- channel opening frequency
Barbs increase Cl- channel opening duration
Post-SAH complication
Vasospasm 4-12 days later. Presents as new onset confusion or focal deficit
Urinary control
1) Sacral micturition center. S2-S4. Stimulates bladder wall
2) Pontine micturition center. In pontine reticular formation. Coordinates ext sphincter with bladder contraction
3) Cerebral cortex. Inhibits sacral micturition center. Damage is cause of incontinence in normal pressure hdyro
Synaptophysin
Marker of neurons, neuroectodermal cells
Precursro amino acid for serotonin
tryptophan
Treatment for serotonin syndrome
Supportive care
cyproheptadine (serotonin receptor antagonist/1st gen antihistamine)
Lacunar infarct
Ischemic stroke involving sm penetrating vessels. Affects basal galnglia, pons, internal capsule, corona radiata
Cansued by chronic HTN that leads to arteriolar sclerosis
Chiari I: pathology and presentation
Low lying cerebellar tonsils that extend through foramen magnum
Typically doesn’t present until adolescence/adulthood. Paroxysmal occipital headache and cerebellar dysfunction
Tensor tympani innervation
V3
