Neurological disorders Flashcards
What are the main factors in the occuring of strokes?
- age
- artherosclerosis
What is artherosclerosis?
- the hardening of arteries vaused by the developing of a layer of plaque inside the blood vesse
What is the main supplier of blood to the cerebral hemispheres?
internal carotid artery
What are the two types of strokes?
1) Hemorragic stroke
2) Ischemic stroke
What is the dominant type of stroke?
ischemic strokes
What are the two main causes of ischemic strokes?
- embolus
- thrombus
What dies the impact of a stroke depend on?
the size of the affected blood vessel
What can be used to diminish the long term impacts of strokes?
- physical therapy
- speech therapy
- occupational therapy
How does the presence of a tumour inside the brain cause neurological problems?
- Compression
- Infiltration
How does compression damage the brain?
- direct destruction of brain tissue
- causes hydrocephalus by blocking the flow of cerebrospinal fluid
What composes a meningioma?
the cells of the dura mater or of the arachnoid membrane
What are the symptoms of meningioma?
Persistent headaches, tingling, weakness
What are the possible causes of encephalitis?
- infection
- toxic chemicals
- allergic reaction
What are the possible causes of meningitis?
- viruses
- bacteria
What are the effects of polio?
destroys motor neurons in the brain and spinal chord
What happens if the herpes simplex virus reaches the brain?
Can cause encephalitis and brain damage
What are the possible effects of TBI and mTBI?
- TBI: scarring in the brain, which augments the risk of seizures
- mTBIs and/or TBIs: increases risks of developing brain problems down the road, as they create long term neurodegeneration
What are the ways in which an open brain injury can damage the brain?
- damage to the portion of the brain directly in contact with the object/bone
- damage to the blood vessel can impar blood flow to certain parts of the brain
- accumulaiton of blood can caused damage through compression
What is the cause of most seizures?
Scarring in the brain
What are the possible causes of scarring in the brain?
- injury
- stroke
- tumour
- developmental abnormality
What are possible causes for seizures?
- scarring in the brain
- high fevers
- withdrawal from GABA agonists
- neural network instability (genetic factors)
when does a seizure cause convulsions?
When it involves motor neurons
What is the difference between a complex and a simple partial seizure?
- complex: causes a loss of consciousness
- simple: does not cause a loss of consciousness
What is the differece between a partial and a generalized seizure?
A partial seizure stays at one spot in the brain (highly localized)
A generalized seizure involves most of the brain (spreads)
What are the different steps of a tonic-clonic seizure?
1) aura
2) tonic (contraction)
3) clonic (rythmic jerking movements)
What are abscence seizures?
Generalized and complex seizures that include an absence spell
Do absence seizures cause brain damage?
not necessarily
What caracterizes an atonic seizure?
loss of muscle tone
What are the possible treatments for seizure disorders?
- anticonvulsants that work by decreasing the effectiveness of inhibitory synapses (benzodiazepines)
- brain surgery (only if medicaiton is inefficient)
What causes fetal alcohol syndrome?
- consumption of alcohol during thw 3rd and 4th week of pregrancy
What is fetal alcohol syndrome associated with?
- facial anomalies
- severe intellectual disabilities
What are inherited metabolic disorders?
genetic abnormalities in which the code for a specific protein is in error
What typically causes inherited metabolic disorders?
enzyme that is not produced because wrongly coded in both ersions of the gene (generally concerns enzymes)
What is a teratogen?
any chemical or toxin that results in abnormal development of the brain
What causes phenylketonuria?
- absence of the enzyme that converts phenylalanine to tyrosine
What causes tay-sachs disease?
lacks of enzymes in lysosomes
What are the effects of tay-sachs disease?
- accumulation of waste produces
- swelling of cells in the brain
What causes Down syndrome?
presence of extra twenty-first chromosomes
What type of disorder is multiple sclerosis?
an autoimmune disorder
What type of disorder is tay-sachs disorder?
Disorder of development (inherited metabolic disorder)
What type of disease is phenylketonuria?
disorder of developemnt (inherited metabolic disorder)
What type of disorder is down syndrome?
disorder of development
What type of disorder is fetal alcohol syndrome?
disorder of development
What does it mean that multiple sclerosis is a sporadic disease?
it is not obviously caused by an inherited gene mutation/infectious agent
What occurs when a person has multiple sclerosis?
their immune system attacks the myelin of different parts of their system, which causes various symptoms of neurological deficiency
How is the progression of multiple sclerosis caracterized?
remitting-relapsing MS at first, then progressive MS
What are the different treatments used for MS?
- interferon B
- glatiramer acetate
What is the effect of interferon B?
Modulates immune system (used in treating MS)
What is the effect of glutiramer acetate?
is a peptide that mimics the effects of myelin (used in the treatment of MS)
What are the 6 main neurodegenerative disorders?
- ALS
- alzheimer’s
- huntington’s
- parkinsons
- dementia
- trasnmissible spongiform encephalopathy
What is a prion?
misfolded protein with the ability to transmit its misfolded shape onto normal variants of the same protein
What makes prion proteins different both from other pathogens and other neurodegenerative diseases?
- only contagious agent that is just a protein
- only neurodegenerative disease that is contagious
Which type of disease is caused by an accumulation of prion proteins?
transmissible spongiform encephalopathy
What causes huntington’s disease?
a mutation in the Huntingtin gene (it is too long), which causes an accumulation of Huntington proteins in the input nuclei of the basal ganglia (striatum), which causes neurodegeneration by disrupting cell function
What are the symptoms of Huntington’s disease?
- severe lack of coordination
- uncontrollable/jerky limb movements
- dementia
- cognitive and emotional changes
What is the treatment under clinical trial for Huntington’s disease?
- anti-sense therapy
What is the aim of anti-sense therapy?
Create an RNA strand that is perfectly complementary to the problematic RNA strand that encodes for the too long Huntington protein, which ends up creating a double helix complex, which then prevents the formation of the protein (no ribosome can have effect) and causes the destruction of this double stranded extra nuclei complex
What type of protein aggregates to create apoptosis in Parkinson’s disease?
- alpha synuclein
What is the name of the aggregates of synuclein proteins?
lewy bodies
Where do lewy bodies form in the onset of Parkinson’s disease?
in the midbrain
What is the effect of the accumulation of lewy bodies in the midbrain?
degeneration of the substantia nigra, mainly caracterized by the apoptosis of dopamine-secreting neurons in the nigrostratial system
What protein is often deficient in parkinsons?
parkin
What is the protein that targets undesirable proteins within the cell for degradation?
ubiquitin
What organelle is responsible for the degradation of ubiquitinated proteins?
proteasome
What are the two broad types of genetic disorders?
toxic gain of function
toxic loss of function
What is L-dopa useful for?
It is used by dopaminergic neurons in the brain to produce more dopamine, which helps deal with the motor symptoms of Parkinson’s disease.
What are the different possible treatments for Parkinson’s disease?
1) L-Dopa
2) Brain lesions
3) deep brain stimulation
What are the regions of the brain targeted by brain lesions and DBS in the treatment of Parkinson’s disease?
parts of the basal ganglia
- subthalamic nucleus
- globus pallidus
What are the possible causes of dementia?
neurodegenerative diseases
What is the main neurological cause of alzheimer’s disease?
aggregation of misfolded B-amyloid proteins
Where is neurodegeneration mostly observed in Alzheimer’s disease?
- hippocampus
- neocortex
What is the main risk factor for Alzheimer’s disease?
TBI
Where is the gene for B-amyloid precursor situated?
chromosome 21
What is amyloid plaque?
The clumps of extra-long B-amyloid protein that form in the brain and cause Alzheimer’s disease
What is the name of the enzyme that cuts B-amyloid precursor protein in shorter strands?
secretase
What is the possible cause of the malfunction of secretase in Alzheimer’s disease?
mutation in presenilin
What is the consequence of the presence of the E4 allele of the apoE gene?
increases the risk of late-onsdt alzheimers
What happens with Tau proteins in Alzheimers?
they become hyper-phosphorylated, form neurofibrillary tangles and disrupt intracellular transport
What are the most studied treatments for Alzheimer’s disease?
Immunotherapy targetting either B-amyloid proteins or tau proteins
What type of neurons are attacked by Amyotrophic lateral sclerosis?
motor neuronsw
Where are the motor neurons that are concerned by amyotrophic lateral sclerosis?
- spinal chord
- cranial nerve
What are the different symptoms that are observed in amyotrophic lateral sclerosis?
- spasticity caused by increased muscle tension
- exaggerated stretch reflexes
- progressive weakness/muscular atrophy
- muscle paralysis
What other disease is on the same spectrum as ALS?
frontotemporal dementia
What explains the fact that two identical twins can deelop sompletely different mental disorders?
the unavoidable randomness at the molecular level that impacts brain development
What are the main periods of symptom flare ups for schizophrenia?
- late teens/early 20s
- menopause
What proportion of the population is affected by schizophrenia?
about 1%
What are the three types of symptoms of schizophrenia, in order of apparition?
1) negative
2) cognitive
3) positive
What are the negative symptoms associated with schizophrenia?
- anti social behaviour
- reduced emotional expression
- poverty of speech
- reduced motivation
What are the cognitive symptoms of schizophrenia?
- disorganized/irationnal thinking
- deficits in learning/memory
- poor abstract thinking
- poor problem solving
What are the positive symptoms of schizophrenia?
- presence of delusions
- hallucinations
What is heritability?
the proportion of phenotype variability associated to genetics
What is the proportion of heritability of schizophrenia?
80%
What are the months of birth that are most likely for people who display schizophrenia?
- march
- february
- may
- april
What do the environmental factors of schizophrenia all have in common?
they all seem to be related to in utero development
What is the biggest risk factor for the development of schizophrenia?
Illness/infection of the mother during pregnancy
What are some anatomical indicators of schizophrenia?
- partial webbing of the two fron toes
- high steeped palate
- variability in the face
What is the effect of most drugs that are used in the treatment of schizophrenia?
- dopamine D2 receptors
What is the relation between dopamine receptor agonists and schizophrenia?
The use of drugs who are dopamine receptor agonists in healthy patients tends to elicit the symptoms that are generally observed in schizophrenia
What are antipsychotics?
Molecules used in the treatment of schizophrenia to relieve the positive symptoms of schizophrenia
What is the dopamine hypothesis of schizophrenia?
- excessive activity of dopamine D2 receptors in the the nucleus accumbens
- hypoactivity of the frontal lobes (dorsolateral prefrontal cortex) caused by a hypoactivity of dopamine D1 receptors
What are the main risk factors to the development of schizophrenia?
- being born in a populous city
- born in february/march/april/may
- childhood trauma
- social isolation
- perinatal hypoxia/brain damage
- pregnancy issues
What are atypical antipsychotics?
- Antipsychotics that are dirty drugs (bind to more than just the dopamine D2 receptors)
What is the mode of effect of clozapine?
- blocks dopamine D2 receptors
- blocks serotonine 2A receptors
What is the mode of effect of aripiprazole?
is a PARTIAL AGONIST of
- dopamine D2
- dopamine D3
- serotonine A1
