Chapter 10 - Brain Damage Flashcards
Another name for tumor
Neoplasm (literally, “new growth”).
Tumor or neoplasm
A mass of cells that grows independently of the rest of the body.
About 20% of tumors found in the human brain are _________ (type of tumor).
Meningiomas
Meningioma
Tumors that grow between the meninges.
All meningiomas are ______ tumors.
Encapsulated
Encapsulated tumor
A tumor that grows within its own membrane.
Particularly easy to identify on a CT scan, and can influence the function of the brain only by the pressure they exert on surrounding tissue.
They are almost always benign tumors.
Benign tumor
A tumor that is surgically removable with little risk of further growth in the body.
Infiltrating tumors
Tumors that grow diffusely through surrounding tissue. As a result, they are usually malignant tumors.
Malignant tumors
Tumors that are difficult to remove or destroy completely, and any cancerous tissue that remains after surgery continues to grow.
Gliomas
Brain tumors that develop from glial cells.
Are infiltrating, rapidly growing, and common.
About ______% of tumors do not originate in the brain, but are grown from infiltrating cells that are carried to the brain by the bloodstream from some other part of the body.
10
Tumors that originate in one part of the body but spread to another are called _______ tumors.
Metastatic
Many metastatic brain tumors originate as cancers of the _____.
Lungs
Stroke
Sudden onset cerebrovascular disorder that causes brain damage. In the United States it is the third leading cause of death, the major cause of neurological dysfunction, and the most common cause of adult disability.
The layer of dead or dying tissue produced by a stroke is called a/n _____.
Infarct
Surrounding the infarct is a dysfunctional area called the ________.
Penumbra.
The tissue in the penumbra may recover or die in the ensuing days. The primary goal of treatment following stroke is to save the penumbra.
There are two major types of strokes:
Those resulting from cerebral hemorrhage
And
Those resulting from cerebral ischemia.
Cerebral hemorrhage
Occurs when a cerebral blood vessel ruptures and blood seeps into the surrounding neural tissue and damages it.
Cerebral ischemia
A disruption of the blood supply to an area of the brain.
Three major causes of cerebral ischemia:
Thrombosis, embolism, and arteriosclerosis.
Contusion
Closed-head injuries that involve damage to the cerebral circulatory system. Produces internal hemorrhaging, which results in a hematoma.
Hematoma
A localized collection of clotted blood in an organ or tissue. A bruise.
Contusions frequently occur on the side of the brain ______ to the side struck by a blow.
Opposite
Contrecoup injuries
Contusions that occur on the side of the brain opposite to the side of a blow.
Toxic psychosis
Chronic insanity produced by a neurotoxin.
Apoptosis (“A-poe-toe-sis”)
Cell death that is actively induced by genetic programs; programmed cell death.
Tumors, cerebrovascular disorders, closed-head injuries, infections, toxins, and genetic factors produce neural damage, in part, by activating _________ programs of ________.
Apoptotic,
Self-destruction.
Necrosis
Passive cell death resulting from injury.
Necrotic cell death is ______- it is typically complete in ______. In contrast, apoptopic cell death is ______, typically requiring ______.
Quick,
A few hours,
Slow,
A day or two.
Many seizures do not take the form of _______; instead, they involve subtle changes of thought, mood, or behavior that are not easily distinguishable from normal ongoing activity.
Convulsions (motor seizures).
In thrombosis, a plug called a _______ is formed and blocks blood flow at the site of its formation.
Thrombus
Thrombosis
The blockage of blood flow by a plug (a thrombus) at the site of its formation.
Embolism
The blockage of blood glow in a smaller blood vessel by a plug (embolus) that was formed in a larger blood vessel and carried by the bloodstream to the smaller one.
Arteriosclerosis
A condition in which blood vessels are blocked by the accumulation of fat deposits on their walls.
Ischemia induced brain damage has two important properties:
- It takes a while to develop. Soon after an episode, there usually is little or no evidence of brain damage. After a day or two substantial neuron loss can often be detected.
- damage does not occur equally in all parts of the brain; particularly susceptible are the neurons in certain areas of the hippocampus.
_______, the brain’s most prevalent excitatory nuerotransmitter, plays a role in ________ damage.
Glutamate,
Stroke-induced
Describe how glutamate damage following a stroke is thought to work.
After a 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 (NMDA) in the membranes of postsynaptic neurons. As a result, large numbers of Na+ and Ca2+ ions enter the postsynaptic neurons. The excessive internal concentrations of Na+ and Ca2+ ions in postsynaptic neurons affect them in two ways: they trigger the release of excessive amounts of glutamate from neurons, thus spreading the toxic cascade to yet other neurons; and they trigger a sequence of internal reactions and ultimately kill the postsynaptic neurons.
Encephalitis
The inflammation associated with brain infection.
Meningitis
Inflammation of the meninges.
The syndrome of insanity and dementia that results from a syphilitic infection is called _______.
general paresis.
There are two types of viral infections of the nervous system:
Those that have a particular affinity for neural tissue and those that attack neural tissue but have no greater affinity for it than for other tissues.
There are two common types of brain infections:
Bacterial infections and viral infections
When bacteria infect the brain, they often lead to the formation of ________.
cerebral abscesses (pockets of pus in the brain).
Toxic insanity
Chronic insanity produced by a neurotoxin.
Some neurotoxins are _______. For example, the body can produce antibodies that attack particular components of the nervous system.
endogenous
Inherited neuropsychological disorders are rarely associated with dominant genes because dominant genes that disturb neuropsychological function tend to be eliminated from the gene pool (individuals who carry one usually have survival and reproductive disadvantages). In contrast, individuals who inherit _________ do not develop the disorder, and the gene is passed to future generations.
one abnormal recessive gene
Genetic ______ is another major cause of neuropsychological disorders of genetic origin.
accident
________, which occurs in about 0.15% of births, is a disorder of genetic accident.
Down syndrome
Down syndrome occurs in the mother during ovulation, when an extra ________ is created in the egg. Thus, when the egg is fertilized, there are three rather than two.
chromosome 21
The probability of giving birth to a child with Down syndrome increases markedly with _______.
advancing maternal age
The probability goes from 1 in 1,667 at maternal age 20 to 1 in 11 at maternal age 49.
There was great optimism for treating neuropsychological disorder when the human genome was documented at the beginning of this century. There has not been a complete cure for all neuropsychological disorders for two reasons:
First, numerous loci on human chromosomes have been associated with each disease- not just one or two.
Second, about 90% of the chromosomal loci involved in neuropsychological disorders were not conventional protein-coding genes; the loci were in poorly understood sections of the DNA.
Tumors, cerebrovascular disorders, closed-head injuries, infections, toxins, and genetic factors produce neural damage, in part, by activating _______.
apoptotic programs of self-destruction.
Cell death is not an either-or situation: some dying cells display signs of ________.
both necrosis and apoptosis
_______ cell death leads to inflammation, while _______ does not.
Necrotic,
apoptosis.
Epileptic auras
Psychological symptoms that precede the onset of a convulsion. May take many different forms– a bad smell, specific thought, vague feeling of familiarity, hallucination, tightness in chest. The nature of the auras provide clues concerning the location of the epileptic focus.
Once an individual has been diagnosed as epileptic, it is usual to assign the epilepsy to one of two categories–
partial epilepsy,
or
generalized epilepsy.
And the to one of their respective subcategories.
The various seizure types are so different from one another that epilepsy is best viewed not as a single disease, but as a number of _____, but related., diseases.
different
Partial seizure
A seizure that does not involve the entire brain.
The epileptic neurons at a focus begin to discharge together in bursts, and it is this synchronous bursting of neurons that produces epileptic spiking in the EEG. The synchronous activity tends to spread to other areas of the brain– but in the case of partial seizures, not the entire brain.
There are two major categories of partial seizures:
Simple and complex
Simple partial seizures
Partial seizures whose symptoms are primarily sensory or motor or both; AKA Jacksonian seizures.
Complex partial seizures
Often restricted to the temporal lobes, and those who experience them are often said to have temporal lobe epilepsy.
During a complex partial seizure, the patient engages in compulsive, repetitive, simple behaviors commonly referred to as automatisms (e.g., doing and undoing a button) and in more complex behaviors that appear almost normal.
About half of all cases of epilepsy in adults are of the complex partial variety — the ______ are particularly susceptible to epileptic discharge.
temporal lobes
Generalized seizures
Involve the entire brain. Some begin as focal discharges that gradually spread through the entire brain. In other cases, the discharges seem to begin almost simultaneously in all parts of the brain. Such sudden onset generalized seizures may result from diffuse pathology or may begin focally in a structure, such as the thalamus, that projects to many parts of the brain.
Tonic-clonic seizure
A type of generalized seizure whose primary behavioral symptoms are loss of consciousness, loss of equilibrium, and a violent tonic-clonic convulsion– a convulsion involving both tonus and clonus.
The ______ that accompanies a tonic-clonic seizure can itself cause brain damage.
hypoxia
Hypoxia
Shortage of oxygen supply to tissue, for example, the brain.
Absence seizure
Not associated with convulsions; their primary behavioral symptom is a disruption of consciousness associated with a cessation of ongoing behavior, a vacant look, and sometimes fluttering eyelids. The EEG of an absence seizure is different from that of other seizures; it is a bilaterally symmetrical 3-per-second spike-and-wave discharge. Absence seizures are most common in children, and frequently cease at puberty.
3-per-second spike-and-wave charge
The characteristic EEG pattern of the petit mal seizure (absence seizure).
Parkinson’s disease
Movement disorder of middle and old age that affects 1-2% of the elderly population. It is about 2.5 times more prevalent in males than in females.
Initial symptoms are mild–perhaps no more than a slight stiffness or tremor of the fingers- but increases in severity over the years. Common symptoms of full-blown disorder are a tremor that is pronounced during inactivity but not during voluntary movement or sleep, muscular rigidity, difficulty initiating movement, slowness of movement, and a masklike face. Pain and depression often develop before the motor symptoms become severe.
Like epilepsy, Parkinson’s disease seems to have no ________; faulty DNA, brain infections, strokes, tumors, traumatic brain injury, and neurotoxins have all been implicated in specific cases. However, in the majority of cases, no cause is obvious, and there is no family history of the disorder. Numerous ______ have been linked to it.
single cause,
genes.
Parkinson’s disease is associated with widespread degeneration, but it is particularly severe in the ________.
substantia nigra (the midbrain nucleus whose neurons project via the nigrostriatal pathway to the striatum of the basal ganglia).
Although ________ is normally the major neurotransmitter released by most neurons of the substantia nigra, there is little ________ in the substantia nigra and striatum of long-term Parkinson’s patients. Autopsy often reveals clumps of proteins in the surviving dopaminergic neurons of the substantia nigra- the clumps are called _______.
dopamine,
dopamine,
Lewy bodies.
Lewy bodies
Clumps of proteins observed in the surviving dopaminergic neurons of Parkinson’s patients.
The symptoms of Parkinson’s disease can be alleviated by injections of ________. However, it is not a permanent solution; it typically becomes less and less effective with continued use, until its side effects (involuntary movements) outweigh its benefits.
L-dopa
The chemical from which the body synthesizes dopamine.
There is currently _______ that will block the progressive development of Parkinson’s disease, or permanently reduce the severity of its symptoms.
no drug
Deep brain stimulation can alleviate severity of Parkinson’s disease for a time, but effectiveness _______ over months. Unfortunately, deep brain stimulation can cause side effects such as ________.
declines,
Cognitive, speech, and hair problems.
Deep brain stimulation
A treatment for neurological disorders (Parkinson’s) that involves the delivery of continuous, low level electrical stimulation to particular brain structures through implanted electrodes.
Stimulation of a nucleus that lies just beneath the thalamus and is connected to the basal ganglia; the sub-thalamic nucleus.
Huntington’s disease
A progressive terminal disorder of motor and intellectual function that is produced in adulthood by a dominant gene.
A progressive motor disorder; but, unlike Parkinson’s, it is rare (1 in 10,000), it has a simple genetic basis, and it is always associated with sever dementia.
The first clinical sign of Huntington’s disease is often _______. As the disorder develops, rapid, complex, jerky movements of entire limos begin to predominate. Eventually, _________ deterioration become so severe that sufferers are incapable of feeding themselves, controlling bowels, recognizing their children. Death occurs about _____ years after first symptoms.
increased fidgetiness,
motor and intellectual,
15
Huntington’s disease is passed from generation to generation by a single mutated dominant gene, called ________. The protein it codes for is known as the ________. Because the gene is dominant, all individuals carrying the gene develop the disorder, as do about half their offspring.
huntington,
huntington protein.
Multiple sclerosis (MS)
A progressive disease that attacks the myelin of axons in the CNS. It is particularly disturbing because it typically attacks young adults.
First, there are microscopic areas of degeneration on myelin sheaths; eventually damage to the myelin is so sever that the associated axons become dysfunctional. Ultimately, many areas of hard scar tissue develop in the CNS.
MS is an _______ disorder– a disorder in which the body’s immune system attacks part of the body.
autoimmune
Common symptoms of advanced multiple sclerosis are:
Visual disturbances, muscular weakness, numbness, tremor, and ataxia. In addition, cognitive deficits and emotional changes occur in some patients.
Ataxia
Loss of motor coordination
Epidemiology
The study of the various factors such as diet, geographic location, sex, and race that influence the distribution of a disease in the general population.
Genetic factors seem to play less of a causal role in multiple sclerosis than they do in other neurological disorders. The concordance rate is only ______ in monozygotic twins, and _____ in dizygotic twins. The incidence of ms is higher in females than in males, and higher in people who have lived in ____ climates, particularly during childhood.
25%,
5%,
colder.
_______ is the most common cause of dementia. About _______ of people over the age of 65 suffer from the disease.
Alzheimer’s disease,
10%
Definitive diagnosis of Alzheimer’s disease must await ________; however, recent cerebrospinal fluid and brain _______ tests have greatly improved early diagnosis.
autopsy,
imaging.
The three defining characteristics of Alzheimer’s disease are:
- Neurofibrillary tangles
- Amyloid plaques
- Neuron loss
Neurofibrillary tangles:
Threadlike tangles of protein in the neural cytoplasm.
Amyloid plaques
Clumps of scar tissue composed of degenerating neurons and a protein called amyloid, which is present in normal brains in only small amounts.
Recently, small dot-like lesions have been noticed in the brain’s of Alzheimer’s patients. These appear to result from ______ and have been termed ________.
microhemorrhages
microbleeds
(In Alzheimer’s patients) Neurofibrillary tangles, amyloid plaques, and neuron loss are particularly prevalent in medial temporal lobe structures such as the ______, _______, and ________ - all structures involved in various aspects of memory.
entorhinal cortex,
Amygdala,
Hippocampus.
Alzheimer’s has a major ______ component. People with an Alzheimer’s victim in their immediate family have a ______ chance of being struck by the disease in old age.
genetic,
50%
One factor complicating the search for a treatment or cure for Alzheimer’s is that-
It is not clear which symptom is primary.
(Alzheimer’s) the amyloid hypothesis is currently the dominant view. It proposes that:
amyloid plaques are the primary symptoms of Alzheimer’s and cause all other symptoms.
The two major categories of epileptic seizures are _______ and _______.
Partial and generalized
_______ are simple repetitive responses that occur during complex partial seizures.
Automatisms
The disorder characterized by tremor at rest is _______ disease.
Parkinson’s
Parkinson’s disease is associated with degeneration in the ______ dopamine pathway.
nigrostriatal
________ disease is passed from generation to generation by a single dominant gene.
Huntington’s
Genetic studies of Parkinson’s disease and Alzheimer’s disease have focused on early-onset _______ forms of the disorder.
familial
Experimental autoimmune encephalomyelitis is an animal model of ________.
multiple sclerosis
The most common cause of dementia is ________ disease.
Alzheimer’s
Two major neuropathological symptoms of Alzheimer’s disease are _______ tangles and _______ plaques.
neurofibrillary,
amyloid.
A 3-per-second spike-and-wave discharge is a sign of
an absence seizure.
Kindling phenomenon
The progressive development and intensification of convulsions elicited by a series of periodic low-intensity brain stimulation– most commonly by daily electrical stimulation s to the amygdala.
Epileptogenesis
Development of epilepsy.
Transgenic
Refers to animals into which genes of another species have been introduced
Anterograde degeneration
The degeneration of the distal segment of a cut axon.
Distal segment
The segment of a cut axon between the cut and the axon terminal
Retrograde degeneration
Degeneration of the proximal segment of a cut axon.
Proximal segment
The segment of a cut axon between the cut and the cell body.
In a laboratory, neural degeneration ensues by cutting axons (axotomy). Two kinds of neural degeneration ensue:
- Anterograde degeneration
- Retrograde degeneration
Anterograde degeneration occurs _______, while retrograde degeneration occurs _______.
(How fast)
He quickly (cut separates the distal segment of axon from cell body, entire distal segment swells within hours, breaks into fragments),
slowly (progresses gradually back from the cut to cell body. In 2 or 3 days, major changes are apparent that are either regenerative or degenerative).
Sometimes, degeneration spreads from damaged neurons to neurons that are linked to them by synapses; this is called ________.
transneuronal degeneration
Degeneration that spreads from damaged neurons to neurons that are linked by synapses.
Transneuronal degeneration
In some cases, transneuronal degeneration spreads from damaged neurons on which they synapse; this is called _________. And in some cases, it spreads from damaged neurons to the neurons that synapse on them; this is called _________.
anterograde transneuronal degeneration,
retrograde transneuronal degeneration
Neuronal regeneration
The regrowth of damaged neurons– does not proceed as successfully in mammals and other higher vertebrates as it does in most invertebrates and lower vertebrates.
Regeneration is virtually nonexistent in the ____ of adult mammals and is at best hit -or-miss in the ______.
CNS,
PNS
In the mammalian PNS, regrowth from the proximal stump of a damaged nerve begins 2 or 3 days after axonal damage, once new growth comes form. What happens next depends on the nature of the injury:
Possibility 1
When a nerve is damaged without severing the Schwann cell sheaths (e.g., by crushing), individual axons regenerate to their correct targets.
In the mammalian PNS, regrowth from the proximal stump of a damaged nerve begins 2 or 3 days after axonal damage, once new growth comes form. What happens next depends on the nature of the injury:
Possibility 2
When a nerve is damaged and the severed ends of the Schwann cell sheaths are slightly separated, individual axons often regenerate up incorrect sheaths and reach incorrect targets.
In the mammalian PNS, regrowth from the proximal stump of a damaged nerve begins 2 or 3 days after axonal damage, once new growth comes form. What happens next depends on the nature of the injury:
Possibility 3
When a nerve is damaged and the severed ends of the Schwann cell sheaths are widely separated, there is typically no functional regeneration.
Clearly, something about the environment of the _______ promotes regeneration and something about the environment of the ______ does not.
PNS,
CNS.
Schwann cells
Myelination PNS axons, clear the debris and scar tissue resulting from neural degeneration and promote regeneration in the mammalian PNS by producing both neurotrophic factors and cell-adhesion molecules. The neurotrophic factors released by Schwann cells stimulate the growth of growth cones and new axons, and the cell-adhesion molecules on the cell membranes of Schwann cells mark the paths along which regenerating PNS axons grow.
Oligodendroglia
Myelination CNS axons, do not clear debris or stimulate or guide regeneration; they release factors that actively block regeneration.
When an axon degenerates, axon branches grow from adjacent healthy axons and synapse at the sites vacated by the degenerating axon; this is called ________.
Collateral sprouting
Cognitive reserve (roughly equivalent to education and intelligence) is thought to play a role in the improvements observed after brain damage that do not result from true recovery of brain function.
Basically, the more intelligence you have, the more you can lose and still have intelligence. These patients have actually recovered lost brain function because their cognitive reserve allowed them to accomplish tasks in alternate ways.
Bilateral transplantation of fetal substantia nigra cells was successful in treating the MPTP monkey model of Parkinson’s disease, and was successful in human trials at first, but after about a year patients began to display a variety of uncontrollable-
writhing and chewing movements
Enriched environments
Those designed to promote cognitive and physical activity– they typically involve group housing, toys, activity wheels, and changing stimulation.
Enriched environments have been shown to increase ______, the size and number of dendritic spines, the size of ______, the rate of adult neurogenesis, and the levels of various neurotrophic factors.
dendritic branching,
synapses.
Phantom limb
Most amputees continue to experience the limbs that have been amputated. Even some individuals (20%) born with a missing limb report experiencing it.
Awareness preserved
Memory preserved
Consciousness preserved
Simple partial seizure
If any of these three are impaired
Awareness preserved
Memory preserved
Consciousness preserved
this is called a
Complex partial seizure
