Chapter 10 - Brain Damage and Neuroplasticity Flashcards
Tumor or Neoplasm
“new growth” - a mass of cells that grows independently of the rest of the body
Encapsulated Tumors
tumors that grow within their own membrane, easy to identify on a CT scan, influence the function of the brain only by the pressure they exert on surrounding tissue and almost always benign tumors
Meningiomas
tumors found in the human brain, grow between the meninges, the three membranes that cover the central nervous system - its an encapsulated tumor
Benign Tumors
tumors that are surgically removable with little risk of further growth in the body
Infiltrating tumors
grow diffusely through surrounding tissue; they are usually malignant tumors
Malignant Tumors
difficult to remove or destroy them completely, and any cancerous tissue that remains after surgery usually continues to grow
Gliomas
brain tumors that develop from glial cells - infiltrating tumors, rapidly growing, and unfortunately the most common form of malignant brain tumors
Metastatic Tumors
grow from infiltrating cells that are carried to the brain by the bloodstream from some other part of the body
Strokes
udden-onset cerebrovascular disorders that cause brain damage; stroke is the fifth leading cause of death, the major cause of neurological dysfunction, and a leading cause of adult disability.
Infarct
area of dead or dying tissue produced by a stroke
Penumbra
area surrounding the infarct; tissue in the penum- bra may recover or die in the ensuing days, depending on a variety of factors.
the primary goal of treatment following stroke is to save the penumbra
Cerebral hemorrhage
bleeding in the brain occurs when a cerebral blood vessel ruptures and blood seeps into the surrounding neural tissue and damages it; common cause is bursting aneurysms
Aneurysm
pathological balloonlike dilation that forms in the wall of an artery at a point where the elasticity of the artery wall is defective; can be congenital (present at birth) or can result from exposure to vascular poi- sons or infection
Cerebral ischemia
disruption of the blood supply to an area of the brain often caused by a blood clot. three main causes of cerebral ischemia are thrombosis, embolism, and arteriosclerosis
Thrombosis
a plug called a thrombus is formed and blocks blood flow at the site of its formation. A thrombus may be composed of a blood clot, fat, oil, an air bubble, tumor cells, or any combination
Embolism
carried by the blood from a larger vessel, where it was formed, to a smaller one, where it becomes lodged; in essence, an embolus is just a thrombus that has taken a trip
Arteriosclerosis
walls of blood vessels thicken and the channels narrow, usually as the result of fat deposits; this narrowing can eventually lead to complete blockage of the blood vessels
Ischemia-induced brain damage
takes a while to develop; oes not occur equally in all parts of the brain—particularly susceptible are neurons in certain areas of the hippocampus
Glutamate
brain’s most prevalent excitatory neurotransmitter, plays a major role in ischemia- induced brain damage
NMDA (N-methyl-D- aspartate) receptors
glutamate receptors that cause blood vessel becomes blocked, many of the blood-deprived neurons become overactive and release excessive quantities of glutamate. The glutamate in turn overactivates glutamate receptors in the membranes of postsynaptic neurons
Closed-head Traumatic brain injury (TBI)
blows that do not penetrate the skull
Contusions
closed-head TBIs that occur when the brain slams against the inside of the skull.
involve damage to the cerebral circulatory system. Such damage produces internal hemorrhaging, which in turn produces a localized collection of blood in the brain—in other words, a bruised brain
Subdural Hematoma
“puddle” of blood; may occur during contusions
Contrecoup Injuries
blow that causes the brain to strike the inside of the skull on the other side of the head
mild TBI (mTBI)
blow to the head with no evidence of contrusion
Chronic traumatic encephalopathy (CTE)
dementia (general intellectual deterioration) and cerebral scarring often observed in boxers, rugby players, American football players (see Figure 10.7), and other individuals who have experienced repeated mTBIs
The Case of Junior Sean
suffered many mTBIs; often experienced severe headaches and would go straight to his darkened bedroom; heavy consumption of alcohol, reckless business and financial decisions, and gambling; requent violent outbursts that were completely out of character for him; at the age of 43, Junior Seau shot him- self. He left no note—no explanation; autopsy of Seau’s brain revealed that he met criteria for a diagnosis of chronic traumatic encephalopathy
Encephalitis
invasion of the brain by microorganisms is a brain infection, and the resulting inflammation
Bacterial Infections
leads to formation of cerebral abscesses (pockets of pus in the brain); major cause of meningitis.
syphilis is a bacterial brain infection.
Types of Brain Infections
bacterial infection and viral infection
Types of Viral Infections
have a particular affinity for neural tissue (ex. rabies) and those that attack neural tissue but have no greater affinity for it than for other tissues (ex. mumps and herpes)
Toxic Psychosis
chronic mental illness produced by a neurotoxin such as heavy metals like mercury and lead; hat makers commonly developed toxic psychosis from the mercury employed in the preparation of the felt used to make hats
Down syndrome
genetic accident associated with Down syndrome occurs in the mother during ovulation, when an extra chromosome 21 is created in the egg. Thus, when the egg is fertilized, there are three chromosome 21s, rather than two, in the zygote; leads to characteristic disfigurement, intellectual disability, early-onset Alzheimer’s disease
Apoptosis
genetic programs for destroying themselves; eliminates extra neurons, and plays a role in brain damage if cells are not damaged too severely, they will attempt to marshal enough resources to destroy themselves via apoptosis
Necrosis
passive cell death resulting from injury
Epilepsy
a brain disease where nerve cells don’t signal properly, which causes seizures
Convulsions
motor seizures; often involve tremors (clonus), rigidity (tonus), and loss of both balance and consciousness
Epileptic auras
peculiar psychological changes just before a seizure; a bad smell, a specific thought, a vague feeling of familiarity, a hallucination, or a tightness of the chest
provides clues concerning location of epileptic focus and warn patient of impending convulsion
Focal Seizure
seizure that does not involve the entire brain.
simple seizures are focal seizures whose symptoms are primarily sensory or motor or both; they are sometimes called Jacksonian seizures after the famous 19th-century neurologist Hughlings Jackson
complex seizures often begin in the temporal lobes and usually do not spread out of them. Accordingly, those who experience them are often said to have temporal lobe epilepsy
International League Against Epilepsy (ILEA) discourages the use of the categories “complex” and “simple.”
Generalized seizures
involve the entire brain.
tonic-clonic seizure: loss of consciousness, loss of equi- librium, and a violent tonic-clonic convulsion (that is, a convul- sion involving both tonus and clonus).
absence seizure: not associated with convul- sions; their primary behavioral symptom is a loss of con- sciousness associated with a cessation of ongoing behavior, a vacant look, and sometimes fluttering eyelids
Parkinson’s disease
movement disorder of middle and old age that affects 1–2 percent of the population over the age of 65; slightly more prevalent in males than in females.
severe in the substantia nigra—the midbrain nucleus whose neurons project via the nigrostriatal pathway to the striatum of the basal ganglia
Huntington’s disease
progressive motor disorder, but, unlike Parkinson’s disease, it is rare (1 in 7,500), it has a simple genetic basis, and it is always associated with severe dementia; passed from generation to generation by a single mutated dominant gene, called huntingtin. The protein it codes for is known as the huntingtin protei
