Degeneration of Nervous system Flashcards
Neurodegeneration
‘Progressive damage or death of neurons leading to a gradual deterioration of the bodily functions controlled by the affected part of the nervous system.’
Acute neurodegeneration
Stroke
Chronic neurodegeneration
Alzheimers, Parkinsons, Huntington’s Chorea
Cerebral stroke
Blockage/interruption of cerebral artery
Death of cells
Symptoms – depend on location
Prevalence of strokes
- In the UK
250-400 strokes per 100 000 people
3rd cause of death
1st cause of disability (in adults)
Ischemic stroke (80%)
Occur when blockage within blood vessel - stops flow or reduces flow to area of the brain
Haemorrhagic (20%)
Individual experiences area of bleeding as blood vessel bursts
High blood pressure
Cerebral arteries under pressure
Haemorrhagic stroke
May experience anuerism
Risk of stroke
At all stages of lifespan
Important factor but can occur at any stage
1 in 4 working age adults
Risk Factors
Age
Medical conditions (high blood pressure, diabetes, high cholesterol etc.)
Lifestyle (smoking, drinking, diet, exercise)
Family history and ethnicity (Likely related to incidence of other risk factors (e.g diabetes, high cholesterol)
Specific for women (pregnancy, contraceptive pill)
Clinical symptoms
symptoms depend on where the stroke is occurring
Sudden or gradual onset
One sided limb weakness/paralysis
Confusion, loss of speech or vision
Headache
Loss of consciousness
= results in dysfunctional cognitive and motor behaviour… determined by size and location of cell loss
Cognitive impairment
Amnesia
Inattention
Confusion
Depression
Mood and behavioural changes
Depression
Common after stroke
Often differ from those with primary depression, they have more cognitive impairment, irritability, more psychomotor slowing and more mood liability
Transient Ischemic Attach (TIA)
Transient episode of neurological dysfunction without acute tissue death
- Disruption of CBF
- Mini-strokes
- Risk factor for subsequent stroke
* 10% strokes within 90 days of TIA
- Silent strokes
* No visible symptoms
Cerebral Stroke pathology
Massive cell death - caused by excessive amounts of glutamate
Inflammation, cell death, reperfusion - trying to re-establish blood flow
Inflammation
Inflammation
- Sodium ions – water, swell, inflammation
Microglia – become phagocytic
Phagocytosis = ‘cell-eating’
Blood-brain barrier breakdown – influx of blood-borne immune cells (neutrophils, macrophages)
Oedema formation, adhesion molecules, cytokines (brain swelling, stroke0
Mechanisms of cell death
Necrosis and Apoptosis
Necrosis
decrease in oxygen
depleted ATP
Cellular swelling and membrane break down
Apoptosis
= triggering of the death programme
Intracellular signalling
Cells fragment into vesicles
Phagocytosis
Hyperperfusion
A major increase in CBF, well above metabolic demands of the CNS tissue
Intracranial haemorrhage/edema
Mortality 36-63%
80% patients significant morbidity
Excitatory neurotransmitters
glutamate and aspartate
Inhibitory neurotransmitters
GABA and glycine
Closely related neurotransmitters
GABA and Glutamate
Lucas and Newhouse 1957
glutamate caused retinal damage
