Chapter 15: Neurological Disorders Flashcards
1
Q
Tumors
A
Mass of cells whose growth is uncontrolled and that serves no useful function
2
Q
Malignant Tumor
A
Cancerous tumor
- Infiltrating: lacks distinct border and may metastasize
3
Q
Benign Tumors
A
No cancerous tumor
- Encapsulated: has distinct border and can’t metastasize
4
Q
Metastasis
A
Process by which cells break off of tumor, travel through vascular system and grow elsewhere in body
5
Q
Compression
A
Can directly destroy brain tissue or indirectly block flow of CSF and cause hydroencephalus
Benign: compression only
Malignant: compression and infiltration
6
Q
Tumor Causes
A
- Come from cell found in the brain that are not nerve cells, or from metastases originating elsewhere in the body
- Most serious types are metastases and gliomas
7
Q
Gliomas
A
Cancerous brain tumor composed of several types of glial cells
8
Q
Tumor Initiating Cell
A
Cells that originate from transformations of neural stem cells, rapidly proliferate, and give rise to glioma
9
Q
Glioblastoma
A
Tumor arise in glial cells
10
Q
Astrocytoma
A
Tumor arise in astrocytes
11
Q
Ependymoma
A
Tumor arise in ependymal cells from the ventricles
12
Q
Oligodendrocytoma
A
Tumor arise in oligodendrocytes
13
Q
Meningioma
A
Tumor arise in cells of meninges
14
Q
Neurinoma
A
Tumor arise in Schwann cells or cells of connective tissue covering cranial nerves
15
Q
Angioma
A
Tumor arise in cells of blood vessels
16
Q
Pinealoma
A
Tumor arise in cells of pineal gland
17
Q
Tumor Treatments
A
- Neurosurgeon removes as much tumor as possible
- Remaining cells are targeted by radiation
- Special type of radiation therapy called stereotactic radio surgery
- Some brain tumors respond to chemotherapy
18
Q
Seizure
A
Period of sudden, excessive activity of neurons in the brain
- If neurons in the motor system are involved, a seizure can cause a convulsion
- Single seizure or many may occur during a lifetime
19
Q
Convulsion
A
Violent sequence of uncontrollable muscular movements caused by a seizure
- Most don’t have convulsions
20
Q
Seizure Disorders
A
Condition that has many causes
- preferred term for epilepsy
21
Q
Partial Seizures
A
Have definite focus, or source of irritation
- Remain localized
- Simple partial seizure
- Complex partial sezure
22
Q
Focus
A
Either a:
- scarred region cáusales by an old injury - developmental abnormality like malformed blood vessel
23
Q
Simple Partial Seizures
A
Can cause changes in consciousness
24
Q
Complex Partial Seizures
A
Lead to loss of consciousness
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Generalized seizures
Widespread, involving most of the brain (grow from focus but origin not discovered)
- Grand mal seizure
- Absence seizure
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Grand mal seizure
Most severe form of seizure
* person experiences aura before seizures
- Tonic and clonic phases
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Tonic phases
First phase of grand mal seizure, in which all patient’s skeletal muscles are contracted
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Clonic phases
Phase of grand mal seizures in which patient shows rhythmic jerking movements
- intense activity of ANS manifests itself in sweating and salivation
29
Absence Seizures
In children cause them to be unresponsive
- characterized by periods of inattention, which aren’t subsequently remembered
- aka petit mal
- can occur up to several hundred times a day
30
Aura
Sensation that precedes a seizure
| - exact nature depends on location of seizure focus
31
Partial seizures
Include sensory changes, motor activity, or both
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Status Epilepticus
Condition in which a patient undergoes a series of seizures without regaining consciousness
- Damage caused by excessive release of Glu during seizure
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Seizure Disorders
Associated with withdrawal from chronic alcohol, barbiturate, and benzodiazepines
- Most common cause: scarring caused by injury, stroke, developmental abnormality, or effects of growing tumor
34
Seizure Treatment
Anticonvulsant drugs
- Increase the effectiveness of inhibitory synapses
Brain surgery
- Usually seizure are eliminated or greatly reduced in frequency
Vagus nerve stimulation
35
Hemorrhagic Strokes
Cerebrovascular accident caused by rupture of cerebral blood vessel
36
Ischemic strokes
Cerebrovascular accident caused by occlusion of blood vessel and interruption of blood supply to region of brain
- Thrombus
- Embolus
37
Thrombus
Blood clot in blood vessels
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Embolus
Piece of material that breaks off and is carried through the bloodstream until it reached an artery too small to pass through
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Immediate cause of neuron death
Excessive amounts of glutamate
40
Cerebrovascular Accidents: Treatments
- Medication to reduce blood pressure
- Brain surgery
- Dissolve or physically remove the blood clot
- Anticoagulant drugs
41
Clot- dissolving drug
tPA- enzyme that helps dissolve fibrin
42
Anticoagulant drugs
Desmoteplase, can restore blood flow if given up to nine hours after occurrence of a stroke
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Cerebrovascular Accidents: Prevention
- Reduce risk factors, such as high BP, smoking, diabetes, high cholesterol
- Carotid endarterectomy to remove atherosclerotic plaque
- Placement of a stent in a narrowed carotid artery
44
After Stroke Treatments
- Drugs that reduce swelling and inflammation
- Physical, speech, and/or OT
- Exercise and sensory stimulation
- Constraint-induced movement therapy
45
Traumatic Brain Injury Types
- Open-head injuries occurs when objects fracture the skull and wound the brain
- Closed-head injuries occur from impacts but do not involve penetration of the brain
- Chronic traumatic encephalopathy (CTE) produced neuro degeneration due to repeated head trauma
- Abnormal tau protein accumulation
- Reduced brain volume and enlarged ventricles
46
Traumatic Brain Injury: Primary and Secondary Treatments
- Reduce swelling and intracranial pressure
- Ensure adequate blood flow to the injured region
- Address symptoms that develop after injury
- Drug that inhibits the release of glutamate
- Similar treatments as with cerebrovascular accidents
47
TBI
Increased adenosine and glutamate
| - promotes inflammation, which causes further damage
48
Teratogens
Any chemical or toxin that results in abnormal development of embryo
49
Fetal alcohol syndrome
Birth defect caused by ingestion of alcohol by pregnant women
- includes characteristic facial anomalies and faulty brain development
50
Phenylketonuria (PKU)
Hereditary disorder caused by absence of enzyme that converts Phe —> Tyr
- Accumulation of Phe causes brain damage by interfering with myelin at ion in CNS
51
Tay-Sachs Disease
Heritable, fatal, metabolic storage disorder
- Lack of enzymes in lysosome causes accumulation of waste products and swelling of cells in brain against folds of dura mater
52
Down Syndrome
Caused by presence of extra chromosome 21
53
Down Syndrome Interventions
Drug treatments may help learning and memory impairment
- GABA antagonists
- Fluoxetine
54
Down Syndrome: GABA antagonists
Overactivity of GABA system may impair hippocampus synaptic plasticity and associated learning and memory
- increases risk of seizures
55
Transmissible Spongiform Encephalopathies
Fatal contagious Brian disease that gives the brain a spongelike appearance
- Cause by simple proteins called prions
56
Prions
Protein that can exist in 2 forms that differ in 3D structure
- Found in membrane of neurons
- Becomes misfolded and causes normal neurons to misfold, killing them
- Resistant to levels of heat that denature normal proteins
57
Accumulation of misfolded, abnormal protein may signal […]
Accumulation of misfolded, abnormal protein may signal apoptosis
- Means by which cells can commit suicide
- Can be triggered externally by chemical signal or internally by disrupted biochemical processes
- Involves production of caspase
58
Caspase
“Killer enzyme” that plays role in apoptosis, or programmed cell death
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TSE can be […], but most cases are […]
TSE can be genetic, but most cases are sporadic
| - Both forms can be transmitted to others
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Sporadic
Disease that occurs rare;y and is not obviously by heredity or an infectious agent
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Parkinson’s Disease Symptoms
- Degeneration of nigrostriatal system
- DA system: substantia nigra —> basal ganglia
- Muscular rigidity, slowness of movement, resting tremor, and postural instability
- Akinesia
- Lewy bodies
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Akinesia
Difficulty initiating movements associated with decreased activation of supplementary motor area
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Lewy bodies
Abnormal circular structures with dense core consisting of a- synuclein protein
- found in cytoplasm of nigrostriatal neurons
64
a-synuclein protein
Found in presynaptic membrane, where it is involved in synaptic plasticity
65
Parkinson’s disease: mutation on chromosome 4
- Produces abnormal a-synuclein
| - Produces a toxic gain of function a protein that results in effects that are toxic to the cell
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Toxic Gain fo Function
Cause by dominant mutation
67
Parkinson’s Disease: mutation of a gene located on chromosome 6
- Produces a gene named Parkin
- Produces a loss of function
- Defective parking fails to ubiquinate abnormal proteins, and they accumulate in the cell, eventually killing it
68
Parkin
Protein that plays trole in ferrying defective or misfolded proteins to proteosomes
69
Loss of Function
Recessive mutation
70
Ubiquitin
Protein that attaches itself to faulty/ misfolded proteins and targets them for destruction by proteosomes
71
Proteasome
Organelle responsible for destroying defective or degraded protein within cell
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Parkinson’s Disease
- Most cases are sporadic
- May be caused by toxin in the environment, faulty metabolism, or unrecognized infectious disorders
- Damages only the nigrostriatal system
- Involves calcium channels
73
Parkinson’s Drug Treatments
L-DOPA produces more DA
- Temporary as symptoms eventually worsen
Deprenyl inhibits the activity of the enzyme MAO-B
- Slows the progression and reduces symptoms
- Does not slow degeneration of DA neurons
74
Parkinson’s Surgical Procedures
- Transplantation of fetal tissue
- Lesioning parts of the brain ti improve symptoms
- GPi
- Implanting electrodes that allow patient to electrically stimulate the brain
- DBS in subthalamic nucleus and GPi
75
Internal Division of Globus Pallidus (GPi)
Division of globus pallidus that provides inhibitory input to motor cortex via thalamus
76
Deep Brain Stimulus
Surgical procedure that involves implanting electrodes in particular region of brain and attaching device that permits electrical stimulation of that region through electrodes
77
Huntington’s Disease Symptoms
- Inherited disorder that causes degeneration of the basal ganglia
- Uncontrallable movements, cognitive, and emotional changes, and eventually death
- Begins in GABAergic medium spiny neurons in putamen
78
Huntington’s Disease Causes
Hereditary disorder caused by dominant gene on chromosome 4
- Produces abnormal protein called huntingtin (Htt)
- Produces a toxic gain of function
- Signals apoptosis
79
Huntingtin (Htt)
Protein that may serve to facilitate production transport of brain-derived neurotrophic factor
- accumulates in nucleus
80
Huntington’s Disease Treatments
Happ1, an antibody that acts intracellularly
- Targets a portion of the Huntington protein
Injection of small interfering RNAs
-Blocks the transcription of the Htt genes
81
Dementia
Loss of cognitive abilities such as memory, perception, verbal ability, and judgement
82
Alzheimer’s Disease
Progressive loss of memory and other cognitive function
- Memory deficit most critically involved recent events
- Abnormal structures develop: amyloid plaques and neurofibrillary tangles
83
Amyloid plaques
Extracellular deposite containing dense core of B-amyloid protein surrounded by degenerating axons and dendrites and activated microclima and reactive astrocytes
84
Neurofibrillary tangles
Dying neuron containing intracellular accumulations of abnormally phosphorylated tau-proteins filaments that formerly served as cell’s internal skeleton
85
Alzheimer’s Disease Abnormal Structure
Abnormal accumulation of long-form AB but little tau protein
| - Induces the release of chemicals that destroy cells
86
Tau Protein
Protein that normally serves as components of microtubules, which provide the cell’s transport mechanism and cytoskeleton
87
B-Amyloid Protein
Protein found in excessive amounts in brains of patients with Alzheimer’s disease
88
Amyloid precursor (APP)
Protein produced and secreted by cells that serves as precursor for B-amyloid that serves a precursor for B-amyloid protein
89
Secretase
Class of enzyme that cut B-amyloid precursor into smaller fragments, including B-amyloid
90
Causes of Alzheimer’s Disease
- Some forms appear to be hereditary
- Mutation of gene that produces APP located on chromosome 21
- Mutation of two presenilin genes located on chromosomes 1 and 14
- Mutation for the gene for apolipoprotein E (ApoE)
91
Presenilin
Produced by faulty gene that causes B-amyloid precursor protein to be converted to abnormal short form
92
Apolipoprotein E (ApoE)
Glycoprotein that transports cholesterol in blood and plays role in cellular repair
- presence of E4 allele of ApoE gene increases risk of late-onset Alzheimer’s disease
93
Alzheimer’s Risk Factors
- TBI
- Obesity, hypertension, high cholesterol levels, and diabetes
- Lower levels of formal education
- Cognitive activity delays the appearance of Alzheimer’s
94
Treatments of Alzheimer’s Diseases
- AChE inhibitors and NMDA receptor antagonists
- No effect on process of neural degeneration and don’t prolong survival
- Noncompetitive NMDA receptor blocker produces slight improvement in symptoms
- Vaccine that destroys AB by sensitizing the immune system to the protein
- Cause inflammation
95
Korsakoff’s Syndrome
- Characterized by symptoms of anterograde amnesia
- Caused by environmental factors, usually related to chronic consumption of alcohol
- Sometimes occurs in people who have been severely malnourished and then received intravenous infusions of glucose
- Deficiency of thiamine produces brain damage
96
Encephalitis Symptoms
- Infection that invades the entire brain
- caused by bacteria, virus, or toxic chemicals
- Symptoms include fever, irritability, and nausea
- often followed by convulsions, delirium, and signs of brain damage
97
Encephalitis Causes
- Herpes simplex virus
- Acute anterior poliomyelitis
- Rabies
- HIV
98
Herpes simplex virus
Attacks the frontal and temporal lobes
| - normally lives in trigeminal nerve ganglia
99
Acute anterior poliomyelitis
(Polio)
| - causes specific damage to motor neurons of the brain and spinal cord
100
Rabies
Passed from saliva by a bite wound
| - Damage CNS and peripheral organs
101
HIV
Causes damage to synapses and death of neurons
102
Meningitis
- Inflammation of meningitis
- Caused by viruses or bacteria
- Symptom: include headache, stiff neck, and sometimes convulsion, confusion or loss of consciousness, and death
- Bacterial meningitis causes brain damage
103
Amyotrophic Lateral Sclerosis
- Spasticity, exaggerated stretch reflexes, progressive weakness and muscular atrophy, and paralysis
- Degenerative disorder that attacks spinal cord and cranial nerve motor neurons
- 10% heredity: mutation in SOD1 gene as chromosome 21
- Toxic gain of function
- 90% sporadic: abnormality in RNA editing
104
Amyotrophic Lateral Sclerosis Treatment
- Riluzole: drug that reduces Glu-induced excitotoxicity
105
Multiple Sclerosis Symptoms
Autoimmune demyelinating disease
- increase in intensity and then decrease, followed by another increase after varying periods of time (remitting-relapsing MS)
- Progressive MS is characterized by slow, continuous increase in symptoms
106
Multiple Sclerosis Causes
- Risk factors include growing up in places far from the equator and being born in late winter or early spring
- May come from a virus
- Causes the immune system to attack own myelin
- Weaken the BBB
- Attaches itself to myelin
107
Multiple Sclerosis Treatment
- Interferon B, a protein that modulates the responsiveness of the immune system
- Glatiramer acetate suppresses the activity of immune cells that would otherwise attack the myelin
- Both are only partially effective treatments for remitting-relapsing form of MS
- Transplantation of autologous hemapoietic stem cells
