Neurology Flashcards
What is the central nervous system (CNS) composed of?
The brain and spinal cord.
What components make up the peripheral nervous system (PNS)?
The somatic nervous system (SNS), autonomic nervous system (ANS), and enteric nervous system (ENS).
What are the three basic functions of the nervous system?
- Sensory function (detecting stimuli),
- Integrative function (analyzing and storing sensory information)
- Motor function (responding to integrative decisions).
What is the function of neuroglia in the CNS?
They support, nurture, protect neurons, and maintain the interstitial fluid around them.
What are the two types of neuroglia that produce myelin sheaths?
Oligodendrocytes (CNS) and Schwann cells (PNS).
How much does the human brain weigh?
Approximately 1.4 kg.
What are the three layers of the spinal meninges?
Dura mater, arachnoid mater, and pia mater.
What is cerebrospinal fluid (CSF) and what are its functions?
CSF is a clear liquid that provides mechanical protection, chemical protection, and circulation for nutrients and waste removal in the CNS.
Where is CSF produced and how does it circulate?
CSF is produced in the choroid plexuses in the ventricles and circulates through the subarachnoid space around the brain and spinal cord.
What is the Monro-Kellie hypothesis?
The hypothesis stating that any increase in the volume of one of the cranial components (brain, blood, CSF) must be compensated by a decrease in one or both of the others to maintain normal intracranial pressure (ICP).
What is hydrocephalus?
A condition caused by the failure of CSF to form or drain normally, leading to increased intracranial pressure (ICP).
What is the role of a ventriculoperitoneal (VP) shunt?
It is a medical device used to divert cerebrospinal fluid from the brain’s ventricles to the peritoneal cavity, commonly used in treating hydrocephalus.
What are the primary arteries supplying blood to the brain?
The internal carotid and vertebral arteries.
What is the blood-brain barrier (BBB) and its function?
The BBB consists of tight junctions between capillary endothelial cells in the brain, which regulate the passage of substances from the blood into the brain, allowing essential substances to pass while excluding harmful ones.
What substances can cross the blood-brain barrier easily?
Lipid-soluble substances such as O2, CO2, steroid hormones, alcohol, nicotine, caffeine, and water.
How can increased intracranial pressure (ICP) be treated?
Treatment can involve diuretics (e.g., Acetazolamide, Furosemide), osmotic diuretics (e.g., Mannitol), steroids (e.g., Dexamethasone), and anti-inflammatory medications.
What is the pathophysiology of cerebral ischemia?
Cerebral ischemia occurs when blood supply to the brain is interrupted, leading to neuronal injury due to lack of oxygen and glucose, which may cause inflammation, increased capillary permeability, and cell death.
What are common predisposing factors for Multiple Infarct Dementia (MID)?
Hypertension, smoking, hypercholesterolemia, diabetes mellitus, carotid artery stenosis, and cardiac problems such as atrial fibrillation.
What is the role of the brain in terms of oxygen and glucose consumption?
The brain, which makes up 2% of body weight, consumes about 20% of the body’s oxygen and glucose, even at rest.
What happens when blood flow to the brain is interrupted for 1–2 minutes?
It impairs neural function. Total deprivation of blood flow for about 4 minutes can cause permanent brain injury.
What is the treatment for increased intracranial pressure due to bleeding or ischemia?
The treatment can include managing the underlying cause, using medications (e.g., anti-inflammatory drugs, osmotic diuretics), and possibly surgery in severe cases.
What is the function of the cerebral cortex?
The cerebral cortex is responsible for higher mental functions such as sensory perception, motor control, and complex cognitive processes like memory and decision-making.
How many neurons are in the human brain?
The human brain contains approximately 100 billion neurons, with about 100 trillion connections between them.
What are association areas in the brain?
Association areas process and integrate sensory information, enabling higher cognitive functions such as memory, learning, and problem-solving.
What is the difference between the right and left hemispheres of the brain?
The right hemisphere is generally responsible for creative and spatial tasks, while the left hemisphere handles language and analytical functions.
What are the physical changes in the brain associated with aging?
Aging can lead to brain atrophy, especially in areas responsible for memory and cognitive function, and a decrease in overall brain volume.
What is the prevalence of Alzheimer’s disease in different age groups?
40-65 years: 1 in 1000
65-70 years: 1 in 50
70-80 years: 1 in 20
80+ years: 1 in 5
What are the key neurological changes in Alzheimer’s disease?
Alzheimer’s disease affects language, memory, intelligence, and personality, leading to emotional and behavioral changes.
How does Alzheimer’s disease affect the brain?
Alzheimer’s disease causes damage to the hippocampus and other brain regions, with the development of plaques and neurofibrillary tangles that impair neuronal function.
What are plaques and neurofibrillary tangles in Alzheimer’s disease?
Plaques are abnormal clusters of amyloid-beta proteins, and neurofibrillary tangles are twisted tau proteins inside neurons, both disrupting brain function.
Which neurotransmitter is commonly targeted in Alzheimer’s treatment?
Acetylcholine is targeted by medications such as Aricept, Galantamine, and Rivastigmine to improve cognitive function by preventing acetylcholine breakdown.
What is multi-infarct dementia?
Multi-infarct dementia is caused by multiple small strokes (cerebral infarcts), gradually impairing mental function as brain tissue is damaged.
What are the risk factors for multi-infarct dementia?
Risk factors include hypertension, smoking, hypercholesterolemia, diabetes, carotid artery stenosis, and atrial fibrillation.
How much brain tissue loss can cause dementia in multi-infarct dementia?
A loss of as little as 10 ml of strategically placed brain tissue may be enough to cause dementia.
What is the progression of dementia in Alzheimer’s disease and multi-infarct dementia?
Dementia progresses as brain regions are increasingly damaged, leading to more severe cognitive and functional decline.
What is hydrocephalus and how does it relate to intracranial pressure?
Hydrocephalus is a condition where abnormal cerebrospinal fluid (CSF) accumulation increases intracranial pressure, potentially causing brain damage.
What is a ventriculoperitoneal (VP) shunt used for?
A VP shunt is a medical device used to redirect cerebrospinal fluid from the brain’s ventricles to the peritoneal cavity to manage conditions like hydrocephalus.
How does cerebral ischemia affect the brain?
Cerebral ischemia occurs when blood supply to the brain is disrupted, leading to a lack of oxygen and glucose, which causes neuronal injury, inflammation, and cell death.
What are the main consequences of cerebral ischemia?
Increased capillary permeability, inflammation, neurotransmitter release, and cytotoxic cell death are key consequences of cerebral ischemia.
What is the main cause of Parkinson’s disease (PD)?
Parkinson’s disease is primarily caused by the degeneration of the basal ganglia and the dopamine-secreting pathway, leading to motor control issues.
How does the loss of dopamine affect the motor cortex?
The loss of dopamine inhibits the motor cortex’s ability to function properly, leading to slower movements (bradykinesia) and rigidity.
What happens when the indirect pathway becomes overactive in Parkinson’s disease?
The overactive indirect pathway, which normally prevents movement, causes the slowed movements and rigidity seen in Parkinson’s disease.
What emotional symptoms are associated with Parkinson’s disease?
- Depression: Feelings of sadness and loss of interest.
- Anxiety: Excessive worry or fear.
- Apathy: Lack of motivation or interest in activities.
- Irritability: Increased frustration or mood swings
- Cognitive changes: Difficulty with memory and concentration.
- Hallucinations and delusions: In advanced stages, causing distress and confusion.
What causes the cell dysfunction and death in Parkinson’s disease?
Cell dysfunction and death in Parkinson’s disease are caused by oxidative stress, mitochondrial dysfunction, loss of nerve growth factors, and apoptosis.
What percentage of the population has a genetic predisposition to Parkinson’s disease?
About 15% of the population has a genetic predisposition to Parkinson’s disease.
Which part of the brain is primarily affected in Parkinson’s disease?
The substantia nigra, a region in the mid-brain, is primarily affected in Parkinson’s disease.
What is the role of Lewy bodies in Parkinson’s disease?
Lewy bodies, formed by misfolded proteins such as alpha-synuclein, accumulate in residual neurons and contribute to the progression of the disease.
What cognitive issue arises as Parkinson’s disease progresses?
As Parkinson’s disease progresses, Lewy body dementia can develop, leading to slow, gradual cognitive impairment.
What are the motor symptoms seen in Parkinson’s disease?
The motor symptoms include resting tremor, bradykinesia (slowness of movement), rigidity, and unintentional muscle movements or twitching.
How does the loss of dopamine affect muscle tone?
The loss of dopamine removes the normal inhibition of muscle tone, leading to increased muscle tone and rigidity.
What is the effect of unopposed cholinergic activity in Parkinson’s disease?
Unopposed cholinergic activity promotes muscle tone, contributing to the rigidity and involuntary muscle movements seen in Parkinson’s disease.
What non-motor symptoms are associated with Parkinson’s disease?
Non-motor symptoms include visual hallucinations, memory disorders, and REM sleep problems.
The lateral ventricles are filled with?
Cerebrospinal fluid
The meninges would be found within which body cavity?
cranial
As intracranial pressure (ICP) rises, brain tissue will become ischaemic and damaged. The pathological mechanisms that might contribute to this damage could include:
A = Inflammation
B= Free Radical production
C= Unregulated cell death
D = All of the above
D = Inflammation, Free Radical production and Unregulated cell death are all pathological mechanisms that might contribute to the damage in brain tissue from risen intracranial pressure
In a healthy person, what increases cerebral blood flow?
An increase in carbon dioxide levels in the blood
What is the name for the middle layer of the meninges that surrounds the brain?
Arachnoid mater
- Julie, aged 19 years came off her motor bike 2 days ago and suffered what she thought was a minor a head injury. After a initial recovery, however, she is now suffering from acute head ache and altered consciousness. Healthcare workers are concerned that she might have raised intracranial pressure due to a cerebral bleed. It is decided that intracranial pressure monitoring should be commenced.
What would be a normal value for intracranial pressure that you might expect Julie to have?
0-15 mmHg
Sam was hit by a slow moving car and catapulted over the bonnet. He sustained abdominal, shoulder and head injuries. When you check his pupils, you find the left larger than the right and not reacting to light:
L= size 6- R=size 3+
Which nerve is being affected in this situation?
Oculomotor nerve (III)
Omar is in a road traffic accident hitting his head on the windscreen and being thrown backwards. He arrives in the emergency department and is diagnosed with raised intracranial pressure from a space-occupying lesion.
What is the most likely cause of the space-occupying lesion that occurs within Omar’s skull?
haematoma
If Omar’s intracranial pressure continues to rise, the brain can potentially herniate through an opening in the skull. What structure would the medulla oblongata potentially move through to cause brain stem death?
foramen magnum
What mnemonic helps remember the cranial nerves?
“Oh Oh Oh To Touch And Feel Very Good Velvet”
Oh: Olfactory
Oh: Optic
Oh: Oculomotor
To: Trochlear
Touch: Trigeminal
And: Abducens
Feel: Facial
Very: Vestibulocochlear
Good: Glossopharyngeal
Velvet: Vagus
, Such: Spinal accessory
Heaven: Hypoglossal
What mnemonic helps remember the nerve class of cranial nerves?
“Some Say Marry Money But My Brother Says Big Boobs Matter Most”
Some: Sensory
Say: Sensory
Marry: Motor
Money: Motor
But: Both
My: Motor
Brother: Both
Says: Sensory
Big: Both
Boobs: Both
Matter: Motor
Most: Motor
What is the function of the Olfactory Nerve (I)?
Senses smell.
What is the function of the Optic Nerve (II)?
Detects vision.
What is the function of the Oculomotor Nerve (III)?
- Controls eye movements (including pupil constriction).
- Controls focusing of the lens.
What is the function of the Trochlear Nerve (IV)?
Controls eye movement (downward gaze, intorson).
What is the function of the Trigeminal Nerve (V)?
- Detects head and face sensations
- Muscles of mastication (chewing)
What is the function of the Abducens Nerve (VI)?
Eye movements (abduction or lacteral movements)
What is the function of the Facial Nerve (VII)?
Controls:
- Muscles for facial expressions.
- Detects taste.
- Lacrimal and Salivary glands.