Neurology Flashcards
(38 cards)
Central Nervous System Intro
-Brain and spine
-integrate information from body
-co-ordinate responses
-seat of consciousness
Peripheral nervous system
-cranial and spinal nerves
-enervate the body
-autonomic and somatic systems
Blood brain barrier
-brain immunologically privileged
-astrocytes wrapped around capillaries
-stops some drugs
Myelin
-lipid rich substance coating some neurones
-glial cells produce
(Schwann cells in PNS, oligodendrocytes in CNS)
-saltatory conduction
Role of Neurotransmitters
-signal transduction, function of NTs tissue dependant.
-cross synapse and bind complementary receptor, receptor activity is regulated
Ionotropic receptors
-ligand gated ion channels
-acts quickly
Metabotropic receptors
-GPCR
-slow reaction
-signal cascade (open another ion channel on membrane)
Glutamate Ionotropic Receptor
-glutamate major excitatory NT in CNS=75%
-allows excitatory cations through Na+, Ca2+,
-depolarize post-synapse cell action potential propangated
-NMDA, Kainate, AMPA
Excitotoxicity
-death and loss of CNS/PNS function
-increased NT levels, glutamate
-excess glutamate Ca2+ influx
-cofactor of endonucleases and proteolytic enzymes
Multiple Sclerosis
-Demyelinating disorder of CNS
-chronic inflammatory condition
-0.1% of pop, 2.5 mill worldwide
MS Predisposing Factors
-Geography (highest temperature)
-Ethnicity (Caucasians)
-Gender (women x2)
-Genes -HLA-DR15
Vitamin D
-deficiency cause MS
-supplements protective
-modulates immune response
Clinical Manifestation of MS
-trauma, pregnancy and infection cause symptoms flare (initiate inflammatory response)
-Symptoms depend on which region of CNS effected:
opticospinal MS
Spinal MS
cerebellar MS
Cause of Symptoms of MS
-progressive and diffuse disease CNS
-autoreactive immune cells target myelin antigens and destroy them (loss of conductivity)
-neurones apoptose (Ca2+ homeostasis disturbed)
Evaluation and Treatment
-McDonald Criteria
-Treatment based on symptoms
modification and
immunosuppressant’s.
Guillain-Barrė Syndrome
-Peripheral neuropathy brought about by demyelination
-Infection cause:
Campylobacter jejuni 30%
Cytomegalovirus 10%
Epstein Barr virus.
Possibly Zika.
-resolves with time 30% ventilator support
Cytomegalovirus (CMV)
-herpes virus
-60-70% of world
-congenital transmission birth defects
-serious disease in immunocompromised individuals
Ion transport in other Neurotransmitters
-reuptake of NTs
-Dopamine (DAT) and serotonin (SERT)
-recycles and controls level of NT in synapse
-Reuptake is facilitated via NT sodium symport.
- Sodium and chloride ion
dependant.
Parkinson’s Disease Intro
-10 millon world wide, 60, 000 annually diagnosed.
-60 years old, usually men
-10% inherited
Presentation of Parkinson’s
- complex motor disorder
-bradykinetic (slowness of voluntary movement)
-postural abnormalities
-tremor
-rigidity
Dopamine
- NT important to motor control
-produced by cells in basal ganglia, substantia nigra
-Contributes to the action
selection process.
-The greater the amount of
dopamine, the less stimulus is
required to trigger movement.
Substantia nigra in PD
- depleted
-underactivity of direct motor pathway
-overactivity of indirect motor pathway
-loss of dopamine=cognitive symptoms depression 40%
Cause of cell death of dopaminergic neurones
Mitochondrial dysfunction.
Oxidative stress.
Inflammation
Lewy bodies in SN of PD, protein aggregates
L-Dopa
-Treatment of PD, also diagnostic
-precursor of dopamine
-dopa decarboxylase converts to dopamine in CNS
-carbidopa adjunct
