A. Brain Damage and Neuroplasticity - Part 1 Flashcards
What are the 6 causes of brain damage?
- brain tumors
- cerebrovascular disorders
- traumatic brain injuries
- infections of the brain
- neurotoxins
- genetic factors
What are neoplasms?
a mass of cells that grow indep of the rest of the body (also known as a brain tumor)
What are the 3 types of brain tumors? Which is the most common? Least common?
- meningiomas
- infiltrating = most common
- metastatic = least common
what are meninges?
Its the membrane layers that encase the brain and spinal cord
What are the 3 layers of meninges?
- outer layer = dura mater
- middle layer = arachnoid mater
- innermost layer = Pia Mater
Describe meningiomas
its a collection of cells encased in the meninges that are usually benign and are easy to remove
What kind of damage do meningiomas cause?
due to being encapsulated in a large mass, it puts pressure on the brain tissue.
what is the significance of John Pinel’s?
He is the author and a person who had Acoustic neuroma (tumor that grew on the acoustic nerve) which was benign and discovered on accident
Describe infiltrating brain tumor
it is a fast-spreading brain tumor that originates in the brain. It is difficult to remove (spreads quickly), is usually malignant, and puts immense pressure on the brain (due to growth speed)
What type of brain tumor is gliomas an example of? Describe
glioma is a build-up of glial cells within the brain. It is an infiltrating brain tumor
Describe the brain tumor type metastatic
It is a type of malignant tumor that doesn’t originate in the brain but instead originates somewhere else and then infiltrates the brain.
Despite metastatic brain tumors being the most deadly why are they the least common of the three types of brain tumors?
malignant cells are one of the many types of cells that the BBB (blood-brain barrier) stops. Therefore, it is unlikely to actually reach the brain
What is an example of a cerebrovascular disorder?
a stroke
Define the terms infarct and penumbra.
infarct is the brain tissue that is severely damaged or dead due to the events of a stroke. Cannot be saved
Penumbra is the slightly damaged brain tissue that surrounds the infarct and can be saved w/ early intervention
T or F - Amnesia and dementia are terms that are interchangeable
F - amnesia is solely related to memory loss while dementia may include memory loss as well as many other mental deficits such as personality changes
T or F - it is possible to repair the infarct if caught in its early stages, however, not if caught too late
F - infarct is dead tissue that cannot be revived no matter what
What are the 2 types of strokes? describe
- cerebral hemorrhage = the BV (blood vessel) ruptures
- cerebral ischemia = there is a disruption in the BV
What can cause a cerebral hemorrhage? describe
an aneurysm = is when the weakened point in a BV receives too much pressure and burst
When a cerebral hemorrhage occurs it results from an aneurysm that bursts the BV releasing the blood from that BV. How does this cause damage to the nearby brain tissue?
blood is toxic to the brain tissue. This is because the components of the RBC get broken down and form free radicals which degrade lipid mem, BBB, and DNA. Causing severe damage and cell death
Both Thrombosis and embolism are types of cerebral ischemia, as they both involve a blood clot blocking the BV cutting off the blood supply to the rest of the brain. So what is the difference b/w these types?
thrombosis is a blood clot that forms in one area and remains static. While embolism is a blood clot that forms in a larger BV and travels until it gets stuck in a smaller BV.
What are the 3 risk factors of cerebral hemorrhage?
- high blood pressure (INC pressure on BV walls)
- smoking (INC viscosity and volume of blood, and forms plaque along the interior of BV walls)
- alcohol = strong correlation
T or F - both cerebral hemorrhage and ischemia both emit their symptoms immediately
F - ischemia strokes don’t show symptoms until potentially days later due to the neurons being able to survive without the blood supply for sometime
What are the 3 causes of cerebral ischemia? describe each
- thrombosis = blood clot
- embolism = blood clot that originated in a larger BV then traveled to a smaller BV
- arteriosclerosis = the thickening of the BV wall
It is said that stents can be used to treat both arteriosclerosis and aneurysms but not thrombosis or embolisms. Why is this?
Stents are a type of treatment that is inserted into a BV to open it wider so the blood is able to properly run through. It also strengthens that wall to prevent it from bursting. This is the reason why arteriosclerosis and aneurysms can be treated using this method. However, thrombosis or embolism are blood clots so expanding the BV walls around these areas will not help as it would result in the clot traveling deeper and getting stuck once again.
T or F - The Damage from an ischemic stroke occurs equally in all parts of the brain
F - the hippocampus has a higher risk
Ischemic strokes cause damage by preventing certain parts of the brain from getting a proper blood supply. How does this result in neuronal damage specifically?
blood-deprived neurons tend to become overactive by releasing too much glu. This in turn overactivation the post-neuronal receptors (NMDA). If this chain of overactivation continues for a long period of time apoptosis of the cell is triggered causing cell death.
Describe a neurotoxic cascade. Include;
a) when it occurs
b) where it occurs
c) how it can be treated
A neurotoxic cascade occurs during an ischemic stroke where the neurons are deprived of blood resulting in an overactive release of glu leading to cell apoptosis. It occurs in the penumbra (tissues surrounding the infarct) and can be treated by exposing the cells to an NMDA antagonist in order to reduce the overactivity of the post cells.
Bonus = drugs or surgery can be an alternative form of treatment
T or F - no mild traumatic brain injuries (TBIs) can result in long-term effects
F - most don’t however if chronic it can
Describe a TBI (traumatic brain injury) and include the locations that it can occur
TBIs are collisions b/w the inner skull and the brain. It can either occur at the site of impact (direct) or on the opposite side of the site of impact (contrecoup)
both contusions and a hematoma can result from a TBI describe these terms
A contusion is the tissue damage that results from the collision, while a hematoma is a pooling of blood within a pocket of the brain (bruise)
TBIs can cause damage at the site of impact directly, however, they can also cause damage on the opposite side of the brain. This is known as contrecoup. How is this possible?
after the initial impact is made a shockwave can displace the brain tissue damaging the tissue on the other side.
subdural hematoma is described as bleeding under the dura (meningitis). As discussed earlier blood is toxic to neurons so why does this only result in damage due to pressure instead of being more severe?
The hematoma (pool of blood) is isolated within a pocket of meningitis thus it never makes physical contact w/ the inner parts of the brain tissue.
Dementia pugilistica also known as ‘punch-drunk syndrome’ is a type of TBI that has long-term severe effects. How does this occur?
It occurs through an accumulation of TBIs such as with boxers, football players, rugby, etc
Describe encephalitis
the inflammation of the brain caused by a micro-organisms
What two types of microorganisms can infect the brain? include the treatments used for both
- bacteria = antibiotics
- viruses = vaccines or anti-viral drugs
Describe Cerebral Abscesses and what causes them
they are pockets of pus caused by bacterial infections
What are the two types of viral infections of the brain? Provide an example for each
- viruses that attack neural tissue exclusively = rabbis
- viruses that just happen to be in the vicinity of neural tissue = mumps, herpes, HIV, Covid
Both bacterial and viral infections can cause meningitis in the brain why is this?
both bacterial and viral infections are types of encephalitis that involve the inflammation of the brain. Thus since meningitis is the inflammation of the meninges both bacteria and viruses can cause it.
Describe the two types of neurotoxins? Give 2 examples for each
- Exogenous = enter from outside the body
ex - Mercury, Lead, antipsychotics - endogenous = from inside the body
ex - antibodies, glu (NTX)
Describe Tardive Dyskinesia and what causes it
An exogenous neurotoxin (antipsychotics) that causes involuntary motion
Describe toxic psychosis and what causes it
An exogenous neurotoxin (lead or mercury) that cause chronic insanity
It is stated that the genetic factors that cause brain damage are mainly recessive genes. Why not dominant?
this is because most dominant genetic causes for brain damage result in the person dying before they can reproduce, preventing the gene from passing on.
Provide an example of a genetic abnormality/mutation that causes brain damage. Which chromosome does it effect and how?
down syndrome = trisomy 21
