When Things Go Wrong Flashcards
What are the symptoms of a seizure?
A person loses consciousness and may fall to the ground, become stiff and shake
What happens during a seizure?
There is an increase in the firing of action potentials by neurons followed by a period of reduced excitability
What is the cyclical process of a seizure modulated by?
Inhibitory (GABA) and excitatory (glutamate) neurotransmitters
What is seizure triggered by?
When the reduction in excitatory is incomplete, seizures may be triggered by uncontrolled recruitment of neighbouring neurons
When is a seizure partial?
When the recruitment of neighbouring neurons is localized
When is the seizure generalised?
When the recruitment of neighbouring neurons spread to the entire cortex
What is the EEG like during a generalised seizure?
Normal alpha rhythm of the EEG is replaced by large, slow, synchronous waves of electrical activity in both cerebral hemispheres
What is epilepsy?
Recurring seizures
What is the treatment for epilepsy like?
- Drugs that dampen down abnormal seizure activity without damping down normal brain activity
- Use brain imaging to localise source of seizures accurately and for neurosurgeon to cut out this brain tissue
What is meninges?
Lining of the brain
What are the symptoms of meningitis?
Fever, headache, neck stiffness, confusion, vomiting, rash for some cases of meningitis like those caused by meningococcal disease
What are the symptoms of migraine?
Feel sick, find bright lights or noises discomforting, experience migrainous aura consisting of flashing lights or jagged lines
Do migrainous aura come before or after the headache?
Before
Which part of the brain does migraine start?
The part that processes pain sensations coming from cerebral blood vessels
What causes symptoms like flashing lights in migraine?
Thee is increase activity in regions that process pain sensations that cause an increase in local blood supply
What causes the temporary weakness in migraines?
After the brief increase in local blood supply, it is immediately followed by reduced blood flow
What drugs that effective at stopping migraine headaches?
Triptans
How do triptans work?
They activate a particular group of serotonin receptors
What causes stroke?
Interruption of energy supply that the brain needs to function
How are fuels delivered to neurons and gila?
Through the four major blood vessels that supply the brain
What are the raw materials to make ATP?
Oxygen and carbohydrate in the form of glucose
What is energy provided used to do?
Driving the flow of charged ions that underlie the electrical activity of neurons, about two thirds of a neuron’s energy is used to fuel an enzyme called Sodium/ Potassium ATPase which recharges the ionic gradients of sodium and potassium after an action potential has occurred
What happens during a transient ischaemic attack (TIA)?
Blood supply to a part of the brain fails and the supply of ATP is interrupted, neurons cannot recharge their ionic gradients and can no longer conduct action potentials
How long does TIA last?
Typically last few minutes and under 24h
Does TIA cause permanent damage?
No
How does TIA pass?
Obstruction passes quickly, neurons can make ATP again, recharge their membranes and normal function will resume
What happens in the absence of ATP?
Cells cannot maintain homeostasis and they may swell up and burst, neurons may also spontaneously depolarise, releasing potentially toxic neurotransmitters such as glutamate and glial cells that mop up excess glutamate through ATP-dependent pump also stops working
What are most strokes caused by?
Blood clots blocking vessels
How to treat strokes caused by blood clots?
“clot-busting” drug called tissue plasminogen activator (TPA) that can break up clot and restore blood flow
What is the condition where people have problem with fine control of movements that make them increasingly unsteady of their feet as years go by?
Spinocerebellar ataxia
What is a neurodegenerative disease associated with abnormal involuntary movements of the body?
Huntington’s disease
What is Huntington’s disease caused by?
Repeat mutation in one of the largest gene in the human genome called huntingtin
What are some early onset forms of Parkinson’s disease caused by?
Problems in gene coding for Parkin
What is a disease characterised by repeated episodes of weakness, numbness, double vision or poor balance that last for a few weeks before recovery?
Multiple sclerosis
What is multiple sclerosis caused by?
Inflammation in the nervous system that flares up and settles down again
What causes demyelination?
When immune system attacks the myelin that wraps around neurons, resulting in a local area of inflammation
What is an autoimmune disease?
When your body’s immune system mistakenly attacks your body
What are the symptoms of demyelination?
Neurological deficits such as vision changes, weakness, altered sensations or behavioural and cognitive problems
What is the relationship between demyelination, autoimmune disease and multiple sclerosis?
Multiple sclerosis is a type of memyelination is a type of autoimmune disease
What can multiple sclerosis attacks be made shorter?
Through drugs like steroids that dampen down the immune system
What are some treatment methods for patients with severe multiple sclerosis?
Permanently dampening down certain parts of immune system with drugs like azathioprine or beta interferon
What causes myasthenia gravis?
Immune system attacking junctions where nerves connect with muscles
What causes Guillaume Barre syndrome?
Immune system attacking the nerves as they emerge from the spinal cord
What is Alzheimer’s disease a form of?
Dementia
What happens as Alzheimer’s disease develop?
Brain cells die, the cortex thins and ventricles enlarge
How can Alzheimer’s disease be confirmed?
Post-mortem during microscopic examination of brain which reveals cell loss and widespread abnormal deposition of an amyloid protein in scattered small degenerating amyloid plagues and fibrillary tangles
What are fibrillary tangles?
Tangled mess of rod-like proteins that are normal constituents of brain cells
What genetic factors can increase the risk of getting Alzheimer’s?
Mutations in genes that encode amyloid precursor protein and presenilins and inheritance of a particular variation of apolipoprotein E (apoE) gene, apoE-4
What does amyloid precursor protein do?
Where amyloid is made
What do presenilins do?
Encode enzymes that break precursor protein down
What has a modest treatment effect on Alzheimer’s?
Nerve cells utilising the chemical transmitter acetylcholine are particularly vulnerable to attack, drugs that block the effect of enzymes that destroy this neurotransmitter boosts the action of the remaining acetylcholine
What are symptoms of depression?
Disturbed sleep, lowered appetite, failing concentration and memory and loss of interest in life
What is the treatment for depression?
Antidepressants that enhance the effect of neuromodulatory transmitters such as serotonin and noradrenaline can treat the disease within weeks, psychological treatments can also be helpful
What is the effect of being chronically stressed?
Unbalancing effect on the control of stress hormones like cortisol which when chronically activated can damage brain cells, particularly in the frontal and temporal lobe
What has been found as an effect of antidepressant drugs?
They promote integrity of brain cells and increase the rate at which new neurons are produced in the hippocampus
What are the symptoms of schizophrenia?
Delusions and hallucinations
What happens to a person’s brain when they have schizophrenia?
Ventricles of the brain enlarge and the activity of frontal lobes becomes impaired
What is treatment is helpful in reducing the frequency and impact of schizophrenia symptoms?
Drugs that block dopamine receptors
What is the result when the brain is activated with drugs like amphetamine?
It is possible to detect abnormalities in the release of dopamine
What does post-mortem studies suggest about schizophrenia?
The way neurons have connected up during development may be abnormal and other neurotransmitter systems like glutamate may be malfunctioning
