Introduction to neurodegenerative diseases Flashcards
When was the reference to the first human brain
egyptian papyrus in 17th century BC
The cerebrum/ cerebral cortex structure
2 hemispheres
- includes subcortical structures
subcortical structures:
- hippocampus
- basal ganglia
- olfactory bulb
The cerebrum is only found in mammals. What is its function?
high order thinking
memory
problem solving
feeling
movement control
What is the function of the hippocampus?
limbic system
short term/ long term memory
spatial memory
What is the function of the basal ganglia?
neurons run through this structure
functions:
- processing centre
- interconnected with cerebrum, thalamus and brainstem
What is the function of the olfactory bulb
processing smells
What is the cerebral cortex
outer layer of grey matter of the cerebrum
What is the difference between grey and white matter?
grey matter = neuronal bodies and other neurological cells
white matter = exons (myelin sheath gives it the white apparence)
What is the function of the frontal lobe (largest lobe)
voluntary movement
conscience (good vs bad)
memories
What is the function of the parietal lobe (located behind the frontal lobe)
integrates sensory information
language processing
What is the functions of the occipital lobe (located caudally of parietal lobe)
visual processing
What is the function of the temporal lobe (inferior to parietal lobe)
sensory input into meaning
long term memory
What is the function of the cerebellum (located posterior and inferior to cerebrum)
coordination and balance
precision
timing
receives sensory information from spinal cord and other parts of brain
What is the function of the brain stem (connectas to the spinal cord, located inferiorly to cerebrum)
controls autonomic functions functions (breathing, digestion, heart rate, blood pressure)
What do each half of the cerebrum control
left = language area and controls movement on right side
right = movement on left side
The brain has billions of neurons which use about 20% of oxygen and ‘fuel’. What is used as fuel for neurons?
sugars and ketone bodies
What is the cause of intracerebral hemorrhage?
hypertension (high BP)
- blood vessels in brain cannot withstand high BP and therefore burst
What is Anencephaly and what is the cause?
no cerebrum formed
- occurs when neural tube does not close properly along its length when fetus is developing
What are common neurodegenerative diseases
alzheimer’s
parkinson’s
huntington’s
multiple sclerosis
amyotrophic lateral sclerosis (motor neuron disease)
- CNS and PNS affected
Alzheimer’s, Parkinson’s and Huntington’s disease are polyglutamine diseases. What does this mean?
different proteins involved in each but the same genetic defect
- CAG trinucleotide expansion causes polyglutamine (polyQ) tract
essentially the misfolding of proteins
- not clear if aggregates cause the disease or is a consequence of the disease
General features of neurodegenerative diseases
spontaneous cause (most cases) or familial (rare)
develop throughout life
- therefore manifests later in life
accumulation of aggregates of protein (intracellular or extracellular) can occur in brain or spinal cord
Amyloidosis is a general feature of many neurodegenerative diseases. What is amyloidosis?
- misfolded proteins cannot completely undergo proteolysis
- therefore hydrophobic sections (beta sheets in proteins) aggregate
- stabilised GAGs and serum amyloid P to form oligomers
- oligomers aggregate further to form amyloid fibrils
Neurodegenerative diseases may lead to dementia. What are the symptoms of dementia?
memory impairment
cognitive defects:
- language
- problem solving
- judgement
- calculation
- attention
- perception
What are the common diagnostic brain technologies
computerised tomography (CT scan)
magnetic resonance imaging (MRI scan)
Positron emission tomography (PET scan)
How does a CT scan work?
X ray beams are absorbed differently by different tissues and structures
x ray beams and detectors are placed around the head to produce a 3D scan
How does and MRI scan work?
places tissues in a magnetic field causing protons to resonate differently and emit different radio waves
- does not expose body to radiation like Ct or x-ray
How does a PET scan work?
based on the use of injected isotopes
- e.g radiolabeled glucose consumption indicates neuronal metabolism
blood oxygen levels
- e.g. radioisotopes of oxygen can indicate brain activity
What can a PET scan detect
brain tumours, strokes, neuronal damage diseases which cause dementia, changes in brain metabolism
easily detectable by PET before structural changes visible in CT and MRI scans
What is the difference between CT, MRI and PET
CT and MRI = detect structural changes
PET = detect changes in metabolism
