Lecture 19 Flashcards
What is the incidence of strokes?
Approximately 750,000/year
What is likelihood of having a stroke related to?
Age
What is the process in which linings of arteries develop a layer of plaque, deposits of cholestrorol, fats, calcium and cellular waste products?
Astherosclerosis
What are the risk factors of astherosclerosis?
High blood pressure
Cigaratte smoking
Diabetes
High blood levels of cholesterol
What is astherosclerosis a precursor of?
Heart attacks and strokes
Where do atherosclerotic plaques often form?
The interal carotid artery
What does the interal carotid artery supply?
Most of the blood flow to the cerebral hemispheres
How can narrowing be visualized?
In an angiogram, produced by injecting a radioplaque dye into the blood and examining the artery with a computerized X-ray machine
What can plaques cause?
What does this cause?
The severe narrowing of the interior of artery.
Greatly increasing the risk of a massive stroke
What is the rupture of a cerebral blood pressure?
A hemorrhagic stroke
What is the occlusion of a blood vessel?
An ischemic stroke
What percentage of strokes are ischemic?
87%
What is the thrombus?
A blood clot that forms within a blood vessel, which may block it and reduce blood flow to the affected area
What is the embolus?
A piece of matter (like a blood clot) that dislodges from its site of origin and occludes an artery in the brain
What can an embolus cause?
A stroke
What does the amount of brain damage vary from? Depending on what?
Negligible to massive
Depending on the size of the affected blood vessel
What can strokes cause?
How can we produce dramtic imrpovements in brain function?
Permanent brain damage
Over days, months and year of physical therapy, occuputional therapy and speech therapy
What are researchers approaches to minimize the amount of brain damage caused b strokes?
has it been found to be succesful?
To adminster drugs that dissolve blood clots in an attempt to reestablish circulation to an ischemic brain region
Meh- benefits only if it is given within 3-4 hours
What are after stroke treatments?
Drugs that reduce sweeling and inflammation
Physical speech and or occupational therapy
Exercise and sensory stimulation (constraint-induced movemnt therapy)
What do the devices that can be deployed through the vascular system to the site of an occlusion do?
They use various strategies to secure and/or remove occlusions
The devices can include
1. aspiration devices
2. incorparated into stents
3. after stroke treatments
What is a mass of cells whose growth is uncontrolled and that serves no useful function?
Tumor
What is a non concerous “benign” tumour that has a distinct border and cannot metastasize?
A non-malignant tumor
What is a cancerous tumour that lacks a distinct border and can metastazie?
A malignant tumour
What is metastasis?
A process by which cells break off of a tumor, travel through the vascular system and grow elsewhere in the body
What is the main difference between malignancy and non malignancy in tumours>
Whether the tumor is encapsulated (whether there is a distinct border)
What happens if there is a border on a tumour?
A surgeon can cut it out becasue it is non malignant it will not regrow
How does a cancerous tumour grow?
What happens?
By infilitrating the surrounding tissue.
There will be no clear cut border between tumor and normal tissue
What happens when surgeons miss some cancer cells?
These cells will produce new tumors
Can any tumor in the brain (regardless of being malignant or benign) produce neurological symptoms and threaten the patients life?
Yes
What are the two means that tumour can damage brain tissue?
Compression and infiltration
How can compression destroy the brain tissue?
Directly: destroy the brain tissue
indirectly: blocking flow of CSF and causing hydrocephalus
What is glioma a type of?
Malignant brain tumour
Where do glioma tumour intiating cells originate from?
Neural stem cells that make glia
What type of tumour is more resistant to chemotherapy and rapidly proliferate?
Gliomas
What is the survuval rate of gliomas?
Low
What is an menigioma an example of?
A non malignant (encapsulated) tumor
What is meningioma composed of?
Cells that constitue the meninges
What causes the right ventricle to be almost completely occluded?
Menigioma
Despite being encapsulate, is the meningioma still damaging?
Yes
What inflammation of the brain, caused by infection, toxic chemicalso or an allergic reaction called?
Encephalitis
What is meningitis?
The inflammation of meninges caused by viruses or bacteria
What are the first symptoms of encephalitis?
Headache, fever and nausea
What are the first symptoms of meningitis?
Headache and stiff neck
What is a viral disease that destroys motor neurons of the brain and spinall cord?
Polio
What is a fatal disease that causes brain damage and is usually transmitter through the bite of an infected animal?
Rabies
What is a virus that normally causes cold sores near the lips or genitals and in rare cases, it instead enters the brain causing encephalitis and brain damage?
Herpes simplex virus
What is a closed head injury?
Caused by a blow to the head with a blunt onject
Coup: brain comes into violent contact with the inside of the skull
Countercoup: brain recoils in opposite direction and smashes against the skull agin
What do open head/penetrating injuries cause damage to?
The portion of the brain that is damanged by the opject or bone
Which percentage of deaths caused by injury involve a TBI?
A third
Where does scarring often form in survuvors of TBIs?
Within the brain, around the sites of injury, which increases the risk of developing seizures
Do mild cases of TBI’s (called mTBIs) increade a persons risk for developing brain problems down the road?
Yes
What is the most common cause of seizures?
scarring, which may relate to an injury, stroke, the irritating effect of a growing tumor or a developmental abnormality in the brain
What are other causes of seizures excluding scarring?
High fevers and withdrawl from GABA agonist
What are many cases of seizures? What does this mean?
Idiopathic
Unknown causes
What can neural network instability and increased risk of seizures come about for?
That affect?
Genetic reasons
- the amount of function of different ion channels in the brain
-the reciprocal wiring of excitatory and inhibitory neurons
-the rules that govern synaptic plasticity
What are most seizure disorders caused by?
Nongenetic factors
What is the preffered term for epilepsy?
Seizure disorder
What happens if neurons that make up motor system are involved?
A seizure disorder can cause a convulsion, which is wild uncontrollable activity of the muscles
Do all seizures cause convulsions?
No
What is a convulsion?
A violent sequence of uncontrollable muscular movemnts caused by seizure
What is a seizure that begins at a focus and remains localized, not generalizing to the rest of brain?
A partial (local) seizure
What is a seizure that does not produce loss of consciousness?
A simple partial seizure
What is a seizure that produces a loss of consciousness?
A complex partial seizure
What is a generalized seizure?
Seizure that involves most of the brain
What is the aura?
What does its exact nature depend on?
Sensation that precedes a seizure.
The location of the seizure focus
What is a tonic clonic seizure?
A generalized, grand mal seizure that typically starts with an aura that is followed by a tonic phase and then a clonic phase. involves convulsions
What is the tonic phase?
First phase of tonic clonic seizure, in which all of the patients skeletal muscles are contracted
What is the clonic phade?
The second phase of a tonic clonic seizure, in which patient shows rhythmic jerking movemnts
Whom are especially susceptible to seizure disorders?
Children
What do children have instead of tonic clonic episodes?
Spells of absence
What are absence seizures?
generalized complex seizures
What happens during absence seizures? (petit mal seizures)
people stop doing what they are doing and stare off into the distance for a few seconds often blinking their eyes repeatedly
How are seizure disorders treated?
How do they work?
Anticonvulsant drugs such as benzodiazepines.
By increasing effectiveness of inhibitory synapses
Do most people with seizure disorders who respons well enough to medications live a normal life?
Yes
Exposure to certain toxins, viruses, and drugs during pregnancy can do what?
Impair fetal brain development and cause intellectual disability
What do dangerous toxins includes?
organophosphates (from insecticides)
heavy metals such as lead and mercury
What is the most dangerous drug during pregnancy?
alcohol
What happens to babies that are born to alcoholic women?
They are typically smaller than average and devlop more slowly
What is fetal alchol syndrome associated with?
Certain facial anomalies and severe intellectual disabilities
What is a particularly serious condition associated with alchol consumption during the 3rd or 4th week of preganancy?
fetal alchol syndrome
What can several inherited “errors of metabolism” cause?
Brain damage or impair brain development
What are genetic abnormalities in which recipe for a particular portein is in error?
Errors of metabolism
What is typically the cause of errors of metabolism?
What happens if it’s a critical enzyme
An enzyme is not synthesized on account of mutation in both copies of the gene.
Results can be very serious
What is a hereditary disorder caused by the absence of enzyme that converts the amino acid phenylanine to tyroside?
Phenylketonuria (PKU)
What can the accumulation of phenylalanine cause?
Unless?
Brain damge
A special diet is implemented soon after birth
What is tay-sachs disease?
An heritable, fatal, metabolic storage disorder
In tay sachs disease what does the lack of enzymes in lysosomes cause?
Accumulation of waste products and swelling in brain
What are phenylktonuria (PKU) and tay-sachs disease examples of?
Metabolid disorders that can affect development of the brain
