Chapter 10: Nervous system Flashcards
Central nervous system
- brain
- spinal cord
peripheral nervous system
- cranial nerves
- spinal nerves
- plexuses
- peripheral nerves throughout the body
cerebrum
thinking, personality, sensations, movements, memory
thalamus
relay station (“triage center”) for sensory impulses; control of awareness and consciousness
hypothalamus
body temperature, sleep, appetite, emotions; control of the pituitary gland
cerebellum
coordination of voluntary movements and balance
pons and midbrain
connection of nerve and nerve fiber pathways , including those to the eyes and face
medulla oblongata
nerve fibers cross over, left to right and right to left; contains centers to regulate heart, blood vessels, and respiratory system
Medulla oblongata
contains 3 important vital centers that regulate internal activities of the body:
1. respiratory center: controls muscles of respiration in response to chemicals or other stimuli
- cardiac center: slows the heart rate when the heart is beating too rapidly
- vasomotor center: affects (constricts or dilates) the muscles in the walls of blood vessels, thus influencing blood pressure
vagus nerve
tenth cranial nerve (cranial nerve X). Its branches reach to the larynx, trachea, bronchi, lungs, aorta, esophagus, and stomach. Latin vagus means wandering. Unlike the other cranial nerves, the vagus leaves the head and “wanders” into the abdominal and thoracic cavities.
cerebell/o
cerebellum
cerebr/o
cerebrum
dur/o
dura mater
- > subdural hematoma
- Hematomas are not tumors of blood, but are collections of blood
encephal/o
brain
- > encephalopathy
- Chronic traumatic encephalopathy is a progressive degenerative disease associated with repetitive brain trauma (concussion)
- > anencephaly
- a congenital brain malformation; not compatible with life and may be detected with amniocentesis or ultrasonography of the fetus
gli/o
glial cells
- > glioblastoma
- this is a highly malignant tumor
lept/o
thin, slender
- > leptomeningeal
- the pia and arachnoid membranes are known as the leptomeninges bc of their thin, delicate structure
mening/o, meningi/o
membranes, meninges
- > meningioma
- slowly growing, benign tumor
my/o
muscle
myel/o
spinal cord
- > poliomyelitis
- Polio- means gray matter. This viral disease affects the gray matter of the spinal cord, leading to paralysis of muscles that rely on the damaged neurons. Effective vaccines developed in the 20th century have made “polio” relatively uncommon.
neur/o
nerve
pont/o
pons
- > cerebellopontine
- the suffix -ine means pertaining to
radicul/o
nerve root (of spinal nerves)
- > radiculopathy
- sciatica is a radiculopathy affecting the sciatic nerve root in the back. A herniated disk is a common cause leading to pain, weakness, or numbness down the leg.
thalam/o
thalamus
thec/o
sheath (refers to the meninges)
vag/o
vagus nerve (10th cranial nerve)
alges/o, algesia
sensitivity to pain
- > hypalgesia
- diminished sensation to pain
- > hyperalgesia
- increased sensitivity to pain
Neuropathies
Are diseases of peripheral nerves. Can affect motor, sensory, and autonomic functions.
- > polyneuropathies affect many nerves
- > mononeuropathies affect individual nerves
-algia
pain
- > Neuralgia
- trigeminal neuralgia involves flashes of pain radiating along the course of the trigeminal nerve
caus/o
burning
- > causalgia
- intense burning pain following injury to a sensory nerve
comat/o
deep sleep (coma)
- > comatose
- a coma is a state of unconsciousness from which the patient cannot be aroused.
esthesi/o, esthesia
feeling, nervous sensation
- > anesthesia
- lack of normal sensation
- > anesthetics
- are agents that reduce or eliminate sensation
- > hyperesthesia
- abnormally intense sensation to a particular stimulus, such as a light touch with a pin. diminished sensitivity to pain is called hypesthesia
- > paresthesia
- means abnormal. paresthesias include tingling, burning, and “pins and needles” sensations
kines/o, kinesi/o, kinesia, kinesis, kinetic
movement
-lepsy
seizure
lex/o
word, phrase
- > dyslexia
- developmental reading disorder occurring when the brain does not properly recognize, process, and interpret language
-paresis
weakness
- > hemiparesis
- affects either the right or left of the body
*paresis also is used by itslef to mean partial paralysis or weakness of muscles
-phasia
speech
-plegia
paralysis (loss or impairment of the ability to move parts of the body)
- > hemiplegia
- affects the right or left half of the body and results from a stroke or other brain injury.
-praxia
action
- > apraxia
- movements and behavior are not purposeful. A patient with motor apraxia cannot use an object or perform a task. motor weakness is not the cause
-sthenia
strength
- > neurasthenia
- nervous exhaustion and fatigue, often following depression
syncop/o
to cut off, cut short
- > syncopal
- syncope means fainting; sudden and temporary loss of consciousness caused by inadequate flow of blood to the brain.
tax/o
order, coordination
- > ataxia
- condition of decreased coordination. Persistent unsteadiness on the feet can be caused by a disorder involving the cerebellum
Neurological disorders may be classified as:
- > congenital
- > degenerative, movement, seizure
- > infectious (meningitis and encephalitis)
- > neoplastic (tumors)
- > traumatic
- > vascular (stroke)
Hydrocephalus
- Congenital disorder
- Abnormal accumulation of fluid (CSF) in the brain
- To relieve pressure on the brain, a catheter can be placed from the ventricle of the brain into the peritoneal space or right atrium of the heart so that the CSF is continuously drained from the brain
- Can occur in adults as a result of tumors and infections
Spina Bifida
- Congenital Disorder
- Congenital defects in the lumbar spinal column caused by imperfect union of vertebral parts (neural tube defect)
- > spina bifida occulta
- the vertebral defect is covered over with skin and evident only on x-ray or other imaging exam.
- > spina bifida cystica
- a more severe form, with cyst-like protrusions
- > meningocele
- the meninges protrude to the outside of the body
- > myelomeningocele
- both the spinal cord and meninges protrude
Alzheimer disease
- Degenerative, Movement, And Seizure Disorders
- Brain disorder marked by gradual and progressive mental deterioration (dementia), personality changes, and impairment of daily functioning
- can occur in middle life but worsens after the age of 70
- Microspocic exam shows senile plaques resulting from degeneration of neurons and neurofibrillary tangles (bundles of fibrils in the cytoplasm of a neuron) in the cerebral cortex
- cause remains unknown, although genetic factors may play a role. a mutation on chromosome 14 has been linked to familial cases
- no effective treatment
Amyotrophic lateral sclerosis (ALS)
- Degenerative, Movement, And Seizure Disorders
- degenerative disorder of motor neurons in the spinal cord and brainstem
- manifests in adulthood
- Signs and symptoms are weakness and atrophy of muscles in the hands, forearms, and legs; difficulty in swallowing and talking and dyspnea develop as the throat and respiratory muscles become affected.
- cause and cure= unknown
Epilepsy
- Degenerative, Movement, And Seizure Disorders
- Chronic brain disorder characterized by recurrent seizure activity
- Tonic-clonic seizures (grand mal or ictal events) are characterized by a sudden loss of consciousness, falling down, and then tonic contractions (stiffening of the muscles) followed by clonic contractions (twitching and jerking movements of the limbs)
-Absence seizures are a form of a seizure consisting of momentary clouding of consciousness and loss of awareness of the person’s surroundings. These include petit mal seizures in children .
- complex partial seizure
- complex means impaired consciousness and partial indicates not generalized. commonly these patients have seizures that cause them to pause in whatever they are doing, become confused, and have memory problems
Huntington’s Disease
- Degenerative, Movement, And Seizure Disorders
- Hereditary disorder marked by degenerative changes in the cerebrum leading to abrupt involuntary movements and mental deterioration
- genetic condition
- symptoms: personality changes, choreic (dance like) movements (uncontrollable, irregular jerking movements of the arms and legs and facial grimacing)-> also known as huntington chorea
- no cure `
Multiple Sclerosis (MS)
- Degenerative, Movement, And Seizure Disorders
- Destruction of the myelin sheath on neurons in the CNS and its replacement by plaques of sclerotic (hard) tissue
- arises in ppl 20-40 years old
- chronic disease marked by long periods of stability (remission) and worsening (relapse)
- demyelination (loss of myelin insulation) prevents the conduction of nerve impulses through the axon. causes paresthesias, muscle weakness, unsteady gait (manner of walking), and paralysis.
- cause is unknown but probably involves an autoimmune disease of lymphocytes reacting against myelin.
- drugs to help treatment
Myasthenia gravis (MG)
- Degenerative, Movement, And Seizure Disorders
- autoimmune neuromuscular disorder characterized by weakness of voluntary muscles.
- chronic autoimmune disorder
- antibodies block the ability of acetylcholine to transmit the nervous impulse from nerve to muscle cell
- brain stem symptoms: ptosis of the upper eyelid, double vision (diplopia), facial weakness, and respiratory paralysis (main clinical concern)
- medications: *anticholinesterase drugs which inhibit the enzyme that breaks down acetylcholine
- corticosteroids (prednisone)
- thymectomy
Palsy
- Degenerative, Movement, And Seizure Disorders
- Paralysis (partial or complete loss of motor function)
- Cerebral palsy is partial paralysis and lack of muscular coordination caused by loss of oxygen (hypoxia) or blood flow to the cerebrum during pregnancy or in the perinatal period
-Bell Palsy is paralysis on one side of the face. Likely cause is a viral infection. Treatment: antiviral drugs and corticosteroids (nerve swelling)
Parkinson’s Disease
- Degenerative, Movement, And Seizure Disorders
- Degeneration of neurons in the basal ganglia, occurring l in later life and leading to tremors, weakness of muscles, and slowness of movement
- caused by deficiency in dopamine
- motor disturbances: stopped posture, shuffling gait, and muscle stiffness (rigidity), masklike lack of facial expression
- Therapy with drugs such as levodopa plus carbidopa (Sinemet) to increase dopamine levels in the brain is palliative (relieving symptoms but not curative).
Tourette syndrome
- Degenerative, Movement, And Seizure Disorders
- involuntary spasmodic, twitching movements, uncontrollable vocal sounds, and inappropriate words
- tics
- cause is unknown but it is associated with either an excess of dopamine or a hypersensitivity to dopamine
- psychological problems do not cause this syndrome but some physicians had success in treating it with antipsyhotic drug haldol, antidepressants, and mood stabilizers
Herpes zoster (shingles)
- > infectious disorder
- viral infection affecting peripheral nerves
- blisters and pain spread along peripheral nerves and are caused by inflammation due to herpesvirus, the same virus that causes chickenpox (varicella)
- shingrix is a vaccine to prevent shingles
Meningitis
- > infectious disorder
- Inflammation of the meninges; leptomeningitis
- can be caused by bacteria (pyogenic meningitis) or viruses (aseptic or viral meningitis)
- signs and symptoms: fever, meningeal irritation (headache, photophobia which is sensitivity to light, and stiff neck)
- lumbar puncture used to examine CSF
- antibiotics=treat the more serious pyogenic form
- antivirals= treat the viral form
human immunodeficiency virus (HIV) encephalopathy
- infectious disorder
- brain disease and dementia occurring with AIDS
- many patients with AIDS develop neurologic dysfunction
Brain tumor
- > Neoplastic disorders
- Abnormal growth of brain tissue and meninges
- can arise from glial cells (gliomas) or the meninges (meningiomas)
- > Types of Gliomas:
- astrocytoma (most malignant form of this is glioblastoma multiforme)
- oligodendroglioma
- ependymoma
- tumors can cause swelling (cerebral edema) and hydrocephalus
- symptoms: severe headache, new seizures
- > Treatments:
- gliomas= can be surgically removed
- brain tumors= treated with chemo and radiotherapy
- steroids= used to treat cerebral edema
-> meningiomas usually are benign and surrounded by a capsule but they may cause compression and distortion of the brain
Cerebral concussion
- > Traumatic disorder
- type of traumatic brain injury caused by a blow to the head
- usually no evidence of structural damage to brain tissue, and loss of consciousness may not occur
- rest is important after a concussion
Cerebral contusion
- > Traumatic disorder
- bruising of brain tissue resulting from direct trauma to the head
- may be associated with edema and an increase in intracranial pressure
- skull fracture may be present
- subdural and epidural hematomas occur leading to permanent brain injury with abnormalities such as altered memory or speech as well as development of epilepsy
Cerebrovascular accident (CVA)
- > Vascular disorder
- disruption in the normal blood supply to the brain; stroke
- also known as a cerebral infarction
Three types:
1. Thrombotic: blood clot (thrombus) in the arteries leading to the brain, resulting in occlusion (blocking) of the vessel. Atherosclerosis leads to this type of stroke. before total blockage occurs a patient may feel symptoms pointing to the gradual occlusion of blood vessels. These short episodes of neurologic dysfunction are known as transient ischemic attacks (TIAs). Treated w/ antiplatelet or anticoagulant therapy
- Embolic: an embolus (a dislodged thrombus) travels to cerebral arteries and occludes a vessel. occurs very suddenly
- Hemorrhagic: A cerebral artery breaks and bleeding occurs. can be fatal. results from age, atherosclerosis, or high blood pressure (all of which result in degeneration of cerebral blood vessels)
- risk factors for stroke: hypertension, diabetes, smoking, heart disease, obesity, substance abuse (cocaine), elevated cholesterol levels
- Tissue plasminogen activator (tPA) may be started after the onset of a stroke
Cerebrovascular accident (CVA): Thrombotic
blood clot (thrombus) in the arteries leading to the brain, resulting in occlusion (blocking) of the vessel. Atherosclerosis leads to this type of stroke. before total blockage occurs a patient may feel symptoms pointing to the gradual occlusion of blood vessels. These short episodes of neurologic dysfunction are known as transient ischemic attacks (TIAs). Treated w/ antiplatelet or anticoagulant therapy
Cerebrovascular accident (CVA): embolic
an embolus (a dislodged thrombus) travels to cerebral arteries and occludes a vessel. occurs very suddenly
Cerebrovascular accident (CVA): hemorrhagic
A cerebral artery breaks and bleeding occurs. can be fatal. results from age, atherosclerosis, or high blood pressure (all of which result in degeneration of cerebral blood vessels)
aneurysm
weakened area in the vessel wall that balloons and may eventually burst
carotid endarterectomy
- removal of the atherosclerotic plaque along with the inner lining of the affected carotid artery)
- used as a means of surgical intervention for stroke
migraine
- > Vascular disorder
- severe, recurring, unilateral, vascular headache
- changes in cerebral blood vessels
- migraine may be associated with an aura
- prevention: sumatriptan succinate (Imitrex) targets serotonin receptors on blood vessels and nerves. drugs of this type reduce inflammation and restrict dilation of blood vessels
absence seizure
form of seizure consisting of momentary clouding of consciousness and loss of awareness of surroundings
aura
Peculiar symptom or sensation occurring before the onset (prodromal) of an attack of migraine or an epileptic seizure.
embolus
clot of material that travels through the bloodstream and suddenly blocks a vessel
ictal event
pertaining to a sudden, acute onset, as with the convulsions of an epileptic seizure
palliative
relieving symptoms but not curing them
thymectomy
removal of the thymus gland used as treatment for myasthenia gravis
tonic-clonic seizure
major (grand mal) convulsive seizure marked by sudden loss of consciousness, stiffening of muscles, and twitching and jerking movements
Cerebrospinal fluid analysis
- > Samples of CSF are examined
- measures protein, glucose, RBC, WBC, other chemical contents
- detect tumor cells (cytology), bacteria, viruses
- diagnoses infection, tumors, multiple sclerosis
Cerebral angiography
- > X-ray imaging of the arterial blood vessels in the brain after injection of contrast material
- diagnose vascular disease( aneurysm, occlusion, hemorrhage) in the brain
computed tomography (CT) of the brain
- > Computerized X-ray technique that generates multiple images of the brain and spinal cord
- shows tumors, aneurysms, bleeding, brain injury, skull fractures, blood clots
- operations are performed using this
- good for visualizing blood and bone
magnetic resonance imaging (MRI)
- magnetic field and pulses of radio wave energy create images of the brain and spinal cord
- better than CT at evaluation of brain parenchyma
- views infection, inflammation, or tumors
- helps diagnose strokes, bleeding problems, and head injury
Magnetic resonance angiography (MRA)
produces images of blood vessels using magnetic resonance techniques
positron emission tomography (PET) scan
radioactive glucose is injected and then detected in the brain to image the metabolic activity of cells
doppler ultrasound studies
sound waves detect blood flow in the carotid and intracranial arteries
electroencephalography (EEG)
Recording of the electrical activity of the brain
-demonstrates seizure activity resulting from brain tumors, other diseases, and injury to the brain
lumbar puncture (LP)
CSF is withdrawn from between 2 lumbar vertebrae for analysis
-aka spinal tap
stereotactic radiosurgery
use of a specialized instrument to locate and treat targets in the brain
