A. Brain Damage and Neuroplasticity - Part 1

Question 1

What are the 6 causes of brain damage?

Answer 1

1. brain tumors
2. cerebrovascular disorders
3. traumatic brain injuries
4. infections of the brain
5. neurotoxins
6. genetic factors

Question 2

What are neoplasms?

Answer 2

a mass of cells that grow indep of the rest of the body (also known as a brain tumor)

Question 3

What are the 3 types of brain tumors? Which is the most common? Least common?

Answer 3

1. meningiomas
2. infiltrating = most common
3. metastatic = least common

Question 4

what are meninges?

Answer 4

Its the membrane layers that encase the brain and spinal cord

Question 5

What are the 3 layers of meninges?

Answer 5

1. outer layer = dura mater
2. middle layer = arachnoid mater
3. innermost layer = Pia Mater

Question 6

Describe meningiomas

Answer 6

its a collection of cells encased in the meninges that are usually benign and are easy to remove

Question 7

What kind of damage do meningiomas cause?

Answer 7

due to being encapsulated in a large mass, it puts pressure on the brain tissue.

Question 8

what is the significance of John Pinel’s?

Answer 8

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

Question 9

Describe infiltrating brain tumor

Answer 9

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)

Question 10

What type of brain tumor is gliomas an example of? Describe

Answer 10

glioma is a build-up of glial cells within the brain. It is an infiltrating brain tumor

Question 11

Describe the brain tumor type metastatic

Answer 11

It is a type of malignant tumor that doesn’t originate in the brain but instead originates somewhere else and then infiltrates the brain.

Question 12

Despite metastatic brain tumors being the most deadly why are they the least common of the three types of brain tumors?

Answer 12

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

Question 13

What is an example of a cerebrovascular disorder?

Answer 13

a stroke

Question 14

Define the terms infarct and penumbra.

Answer 14

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

Question 15

T or F - Amnesia and dementia are terms that are interchangeable

Answer 15

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

Question 16

T or F - it is possible to repair the infarct if caught in its early stages, however, not if caught too late

Answer 16

F - infarct is dead tissue that cannot be revived no matter what

Question 17

What are the 2 types of strokes? describe

Answer 17

1. cerebral hemorrhage = the BV (blood vessel) ruptures
2. cerebral ischemia = there is a disruption in the BV

Question 18

What can cause a cerebral hemorrhage? describe

Answer 18

an aneurysm = is when the weakened point in a BV receives too much pressure and burst

Question 19

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?

Answer 19

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

Question 20

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?

Answer 20

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.

Question 21

What are the 3 risk factors of cerebral hemorrhage?

Answer 21

1. high blood pressure (INC pressure on BV walls)
2. smoking (INC viscosity and volume of blood, and forms plaque along the interior of BV walls)
3. alcohol = strong correlation

Question 22

T or F - both cerebral hemorrhage and ischemia both emit their symptoms immediately

Answer 22

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

Question 23

What are the 3 causes of cerebral ischemia? describe each

Answer 23

1. thrombosis = blood clot
2. embolism = blood clot that originated in a larger BV then traveled to a smaller BV
3. arteriosclerosis = the thickening of the BV wall

Question 24

It is said that stents can be used to treat both arteriosclerosis and aneurysms but not thrombosis or embolisms. Why is this?

Answer 24

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.

Question 25

T or F - The Damage from an ischemic stroke occurs equally in all parts of the brain

Answer 25

F - the hippocampus has a higher risk

Question 26

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?

Answer 26

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.

Question 27

Describe a neurotoxic cascade. Include; a) when it occurs b) where it occurs c) how it can be treated

Answer 27

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

Question 28

T or F - no mild traumatic brain injuries (TBIs) can result in long-term effects

Answer 28

F - most don't however if chronic it can

Question 29

Describe a TBI (traumatic brain injury) and include the locations that it can occur

Answer 29

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)

Question 30

both contusions and a hematoma can result from a TBI describe these terms

Answer 30

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)

Question 31

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?

Answer 31

after the initial impact is made a shockwave can displace the brain tissue damaging the tissue on the other side.

Question 32

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?

Answer 32

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.

Question 33

Dementia pugilistica also known as 'punch-drunk syndrome' is a type of TBI that has long-term severe effects. How does this occur?

Answer 33

It occurs through an accumulation of TBIs such as with boxers, football players, rugby, etc

Question 34

Describe encephalitis

Answer 34

the inflammation of the brain caused by a micro-organisms

Question 35

What two types of microorganisms can infect the brain? include the treatments used for both

Answer 35

1. bacteria = antibiotics 2. viruses = vaccines or anti-viral drugs

Question 36

Describe Cerebral Abscesses and what causes them

Answer 36

they are pockets of pus caused by bacterial infections

Question 37

What are the two types of viral infections of the brain? Provide an example for each

Answer 37

1. viruses that attack neural tissue exclusively = rabbis 2. viruses that just happen to be in the vicinity of neural tissue = mumps, herpes, HIV, Covid

Question 38

Both bacterial and viral infections can cause meningitis in the brain why is this?

Answer 38

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.

Question 39

Describe the two types of neurotoxins? Give 2 examples for each

Answer 39

1. Exogenous = enter from outside the body ex - Mercury, Lead, antipsychotics 2. endogenous = from inside the body ex - antibodies, glu (NTX)

Question 40

Describe Tardive Dyskinesia and what causes it

Answer 40

An exogenous neurotoxin (antipsychotics) that causes involuntary motion

Question 41

Describe toxic psychosis and what causes it

Answer 41

An exogenous neurotoxin (lead or mercury) that cause chronic insanity

Question 42

It is stated that the genetic factors that cause brain damage are mainly recessive genes. Why not dominant?

Answer 42

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.

Question 43

Provide an example of a genetic abnormality/mutation that causes brain damage. Which chromosome does it effect and how?

Answer 43

down syndrome = trisomy 21