HLTH nervous system pt 2 Flashcards
hydrocephalus
is an accumulation of CSF in the skull common in infants because their sutures have not closed yet; 2 forms
2 types of hydrocephalus
noncommunicating/ obstructive and communicating
noncommunicating hydrocephalus
occurs when the flow of CSF through the ventricles is blocked and results from stenosis or a neural tube defect; ventricles gradullary dilate and enlarge, creating pressure
communicating hydrocephalus
occurs when the absorption of CSF from the arachnoid villi is impaired, leading to increased ICP
cause of hydrocephalus
developmental abnormalities (stenosis or atresia), thickened arachnoid mater, tumor, infection, or scar tisse
atresia
lack of an canal or opening; can cause noncommunicating hydrocephalus
signs of hydrocephalus
increased head size in infants, dilated scalp veins, sunset sign, lethargy, and signs of increased ICP
sunset sign
is when the white sclera is visible above the coloured iris
spina bifida
refers to a group of neural tube disorders that are congenital, and often is a result of the failure of the posterior spinous processes of the vertebrae to fuse
how does the neural tube develop?
during the 4th week and extends from the cervical area into the lumbar
spina bifida occulta
occurs when the spinous processes do not fuse and herniation of the spinal cord and meninges does not occur and usually is diagnosed by a dimple on the skin
meningocele
occurs when the spinous processes do not fuse but herniation of the spinal cord and meninges occurs, forming a sac of CSF
myelomeningocele
is the most serious form of spina bifida and occurs when herniation of the spinal cord, nerves, and meninges occurs and results in considerable neurological impairment
causes of spina bifida
genetic and environmental (lack of vitamin A or folic acid, gestational diabetes, and radiation)
signs of spina bifida
vary depending on which type but may be a sac forming a bulge on the skin, muscle weakness, paralysis, and impaired bladder control
cerebral palsy
is characterized by motor impairment in which the brain is damaged during development by hypoxia, hypoglycemia, hyperbilirubinemia, hemorrhage, infection, or trauma, in which the brain becomes necrotic
how does the brain appear in cerebral palsy?
necrotic
kernicterus
occurs when bilirubin crosses the blood-brain barrier and damages neurons
most common type of cerebral palsy
spastic paralysis
spastic paralysis in cerebral palsy
most common type and results from damage to the pyramidal tracts or the motor cortex, causing hyperreflexia and increased muscle tone
signs of spastic paralysis
crossed legs, scissors gait, and unilateral use of the hands and feet
dyskinetic cerebral palsy
results from damage to the extrapyramidal tracts or basal nuclei, causing athetoid (slow, involuntary writhing) or choreiform (rapid, jerky) involuntary movements and loss of coordination with fine movements
athetoid meaning
slow, involuntary writhing; present in dyskinetic CP
choreiform meaning
rapid, jerky movements; present in dyskinetic CP
ataxic cerebral palsy
results from damage to the cerebellum and causes loss of balance and coordination
what besides motor function is impaired in cerebral palsy?
intellectual function, speech, communication, vision, and increased risk of seizures
generalized seizures
have multiple foci or origins in deep structures of both hemispheres and the brainstem; causes loss of consciousness
partial seizures
have a specific foci and may not cause loss of consciousness; may progress to generalized seizures
cause of a seizure
a sudden, uncontrollable depolarization of neurons in the brain causing abnormal motor and sensory activity
status epilepticus
are recurrent or continuous seizures that occur without recovery of consciousness
how does the blood change with seizures?
acidosis, hypoglycemia, hypoxia, and decreased BP may all develop
precipitating factors to seizures
physical stimuli like bright lights and biochemical stimuli like stress, hyperventilation (alkalosis), excessive fluid retention or hypoglycemia
2 types of generalized seizures
absence and tonic-clonic
absence (petit mal) seizures
common in children and is a brief loss (5-10 seconds) of consciousness with possible twitches of eyes and lips
tonic-clonic (grand mal) seizures
generalized seizures and classic understanding of seizures
signs of a tonic-clonic seizure
prodromal signs may occur hours earlier, followed by an aura, loss of consciousness, tonic and clonic contractions, and foaming at the mouth
partial seizures signs
repeated motor movements like jerking of the legs, head movements, tingling, and ringing in the ears; consciousness is retained although memory of the episode may be impaired
Jacksonian seizure
is a focal seizure in which motor signs/ contractions begin in a specific area and spread
temporal lobe or psychomotor seizures
are partial seizures and originate in the temporal lobe but may spread to the frontal lobe and limbic system; may result in hallucinations and bizare behaviour
drug used for seizures
phenytoin which raises the threshold for neuron stimulation
multiple sclerosis
is a progressive demyelination of the neurons of the brain, spinal cord, and cranial nerves; is characterized by remissions and exacerbations
how does multiple sclerosis develop?
an inflammatory response causes a lesion and cells that normally don’t enter the brain do, and attack the myelin of neurons
plaques meaning
are areas of demyelination and inflammation in MS which are normally located near the ventricles, the brain stem, and optic nerve
how does the appearance of the brain change with multiple sclerosis?
is first appears pink and swollen, then grey and firm
cause of multiple sclerosis
not understood but believed to be an autoimmune disorder caused by environmental, genetic, and immune components
early sign of multiple sclerosis
blurred vision
signs of multiple sclerosis
blurred vision, weakness in the legs, diplopia, dysarthria, paresthesia, and a spot in the visual field; later this progresses to immobility problems, emptying problems, and sexual dysfunction
CSF in multiple sclerosis
elevated proteins, gamma globulin, and lymphocytes
parkinson’s disease
is a progressive, degenerative disorder affecting the extrapyramidal tracts due to changes in the basal nuclei, specifically the substantia nigra, leading to a decrease in dopamine and an increase in general muscle tone
what does the deficit in dopamine in parkinson’s lead to?
an imbalance between excitation and inhibition of the basal nuclei
characteristic of dementia
decreased number of cortical neurons
general signs of parkinson’s
increased tremors, pill rolling motion, shuffling gait, increased muscle tone and activity, muscular rigidity, and difficulty initiating movement
cause of parkinson’s
linked to viruses and toxins, leading to changes in the mitochondria and release of free radicals
lewy bodies
are presence of clumps of specific substances in brain cells which are present in parkinson’s
early signs of parkinson’s
fatigue, muscle weakness, muscle aching, and decreased flexibility
Lou Gehrig disease
is another name for ALS
ALS
is muscle wasting and hardening of the lateral corticospinal tracts which affects UMNs and LMNs
cause of ALS
astrocytes secrete a neurotoxin leading to degeneration of motor neurons
what is not affected in ALS?
sensory neurons, cognitive function, and cranial nerves III, IV, and VI
early signs of ALS
weakness and atrophy at the hands and digits
signs of ALS
weakness, atrophy, falls, muscle cramps, paralysis, loss of speech, and impaired respiration
myasthenia gravis
is an autoimmune disorder that impairs receptors for AcH at the neuromuscular junction due to immunoglobulin G autoantibodies, preventing stimulation of the muscle
cause of myasthenia gravis
is often associated with thymus disorders like hyperplasia or a benign tumor
what areas of the body are affected first in myasthenia gravis?
the face and eyes, followed by the trunk and arms
signs of myasthenia gravis
muscle weakness, ptosis and diplopia, facial expressions are lost, impaired chewing and swallowing, and dropping head
myasthenic crisis
can be due to stress or infection and causes increased muscle weakness in myasthenia gravis
huntington’s disease
is a inherited disorder that does not manifest until midlife, in which there is progressive atrophy of the brain, causing degeneration of neurons
what areas of the brain are affected in huntington’s?
the basal ganglia and frontal cortex
what levels are reduced in huntington’s?
GABA and ACh
inheritance of huntington’s disease
autosomal-dominant trait on chromosome 4
signs of huntington’s
mood swings, personality changes, restlessness, jerky movements, and possible intellectual impairment
dementia
is an umbrella term for disorders in which cortical function is decreased, impairing cognitive and motor skills, memory, and causing personality changes
causes of dementia
vascular disease, infections, toxins, and genetic
most common type of dementia
alzheimer’s
pathophysiology of alzheimer’s
cortical atrophy leading to dilated ventricles and widening of the sulci, and the development of neurofibrillary tangles and senile plaques, as well as a defect of ACh
plaques in alzheimer’s
are found in neurons and disrupt neural conduction through beta-amyloid precursor protein
causes of alzheimer’s
is genetic in many cases, in which the gene is autosomal dominant and may be carried in chromosomes 1, 14, 19, and 21
vascular dementia
is caused by cerebrovascular disease and frequently is a result of multiple, small brain infarctions and is common in those with hypertension
Creutzfeldt–Jakob Disease
is a rare form of dementia with a long incubation period but progresses rapidly and is caused by a prion which alters the shape of normal host PrPs, causing rapid destruction of neurons and production of plaques and vacuoles in the neurons
AIDS dementia
in common in the late stages of AIDS when viruses like toxoplasma and candida invade brain tissue, causing impaired cognitive and motor function
changes in the brain in schizophrenia
decreased grey matter in the temporal lobes, enlarged ventricles, excessive dopamine secretion, abnormal cells in the hippocampus and decreased BF to the temporal lobes
cause of schizophrenia
genetic along with brain damage in the fetus, usually the cause of a virus
positive schizophrenia symptoms
delusions and bizare behaviour
negative schizophrenia symptoms
flat emotions and decreased speech
general schizophrenia signs
disorganized thought patterns, meaningless repetition of words, delusions of false beliefs, hallucinations, impaired attention, and social withdrawl
cause of depression
decreased activity by excitatory neurotransmitters in the brain, including serotonin and norepinephrine
signs of depression
prolonged period of sadness and hopelessness, decreased appetite and lipido, lack of energy and self esteem, sleep disorders, and irritability
panic disorder vs panic attack
panic disorder is when attacks are frequent and prolonged in situations that are not life threatening
cause of panic disorder
an increased discharge of neurons in the temporal lobes and biochemical abnormalities involving norepinephrine, serotonin, and GABA
herniated disc
involves the protrusion of the nucleus populous through a tear in the outer covering of the disc, and this exerts pressure on the spinal root and interferes with nerve conduction
most common locations for herniated discs
L4 to L5 and sometimes L5 to S1
lumbosacral herinations
causes pain in the lower back that radiates down one or both legs
what actions radiate sciatic nerve pain?
coughing and straight leg raising
cervical herination
causes pain in the neck and down the arms
