Unit 12 Nervous System Flashcards
Structure of CNS
- Brain-within the skull
- spinal cord
Functions of the nervous system
- Receives information from the body
- processes & interprets information
- produces a response
Normal circulation of CFS and structural components required
CSF circulation starts from:
2 lateral ventricles through interventricular formamina, into 3rd ventricle, through cerebral aqueduct, into 4th ventricle through lateral and medial apertures into subarachnoid space of brain
Brain trauma: concussion
Loss of cerebral control following injury
Immediate and temporary disturbance of brain function, disruption of normal electrical activity
Concussions result in
–blood leaking into the brain
–injection of spinal fluid into the brain, molecular (chemical) disturbance
Symptoms of concussions
–drowsiness, loss of coordination,
-slow pulse, convulsions, projectile vomiting, stupor, comatose
Contusion (bruise)
crushing (compression) of the brain
•leads to hemorrhage
•often accompanied by swelling
•caused by fracture or trauma to the skull
Laceration
cutting wound that penetrates the skull
-results in hemorrhage
extradural hemorrhage
- due to fracture or trauma to the head
- blood collects & proceeds down to brain
- if unrelieved, death can occur in days or weeks
subdural hemorrhage
more severe fracture or injury
- more rapid bleeding
- if unrelieved, death can occur w/in a few days
subarachnoid hemorrhage
most severe, due to laceration
- very rapid bleeding into the brain
- death can occur w/in hours
meningitis
inflammation of the meninges
- caused by microorganisms that spread into blood & CSF
- may affect any age group
bacterial meningitis
(neisseria meningitides)
- life threatening
- may cause epidemic meningitis
- spread by respiratory secreations
other causes of bacterial meningitis include
viruses, fungi, protozoans & cancers
fungal meningitis
common in people w/ impaired immune systems (AIDS)
symptoms of meningitis
headaches, stiff neck, fever, photophobia, vomiting
Cerebrovascular Accident (CVA)
- Apoplexy/stroke
- sudden death of some brain cells due to lack of oxygen caused by blockage or rupture of an artery in the brain
- effect depends on size of the hemorrhage
- 3rd leading cause of death
Predisposing factors of Cerebrovascular Accident (CVA)
- arteriosclerosis
- high blood pressure
- thrombus or embolus in cerebral blood vessel,
- aneurysm
most common symptom of CVA
eakness or paralysis of one side of the body with partial or complete loss of voluntary movement or sensation in a leg or arm
Transient Ischemic Attack (TIA)
temporary lack of circulation to a part of the brain
temporary symptoms of Transient Ischemic Attack
- loss of sensation, movement, speech, mental function or vision
- signs & symptoms generally disappear completely within 24 hours (after resumption of blood-flow)
Hydrocephalus
Excessive accumulation of CSF in the ventricles of the brain
hydrocephalus is usually due to
•obstruction of flow of CSF out of the brain
–congenital defect
–in newborns: toxoplasmosis (parasite in cat liter)
–infection (encephalitis), brain tumor
hydrocephalus can result in
- brain damage, mental changes
- bulging eyes, tight scalp, prominent head vein
Encephalitis
inflammation of brain tissue
encephalitis is caused by
- bacteria (staph, strep)
- viruses
- complication of measles or chicken pox
- infections usually spread from upper respiratory tract, sinuses, ears, or eyes
Symptoms of Encephalitis
- swelling of the brain
- fever, headache, body aches, skin rash & swollen lymph nodes
- severe infections - high fever, stiff neck, stupor (sleepiness), disorientation, coma, tremors, occasional convulsions, paralysis, & rarely death
death rate for encephalitis
3% to 15% (higher in elderly than in younger)
Neurosyphilis
late stages of syphilis often affect the brain and spinal cord
damage to the brain caused by neurosyphilis
–include general paresis (incomplete paralysis)
–can result in dementia, deafness, blindness, paralysis, insanity
damage to the spinal cord due to neurosyphilis
Tabes Dorsalis = slowly progressive degeneration of the spinal cord that occurs in late phase of syphilis, results in locomotive ataxia (wobbliness)
Cerebral Abscess
mass of immune cells, pus, and other material draining into deeper brain tissue
cerebral abscesses are usually from
bacterial or fungal infection
–bacteria can get to the brain from injury, respiratory tract, ear or eye infection
Cerebral Abscess results in
•results in necrosis of healthy brain tissue
–encephalomalacia (brain softening)
Encephalomyelitis
acute inflammation of the brain (encephalo-) & spinal cord (myelo-)
•can be caused by viruses which infect the nervous system
acute disseminated encephalomyelitis
–occurs most commonly after acute viral infection such as measles (rubeola) autoimmune attack on nervous system
Poliomyelitis (Polio=Infantile Paralysis)
inflammation of the spinal cord
•Highly infectious, mainly affects children under 5
•Spread through oral or fecal-oral route
Poliomyelitis results in
–Fever, headache, sore throat, abdominal pain
–Stiffness of neck, trunk, extremities
–Atrophy of group of muscle
–Paralysis in hours (e.g., respiratory, GI tract or leg)
Rabies
acute viral infection of the central nervous system of warm-blooded animals (wolves, cats, dogs)
•transmitted by bite of rabid animal (rabies=madness, rage, fury)
•if left untreated,100% fatal in animals
Rabies results in
–hydrophobia (fear of water, attempts to drink water trigger laryngeal spasm)
–increase in saliva production
–abnormal behavior
–paralysis–> respiratory failure–>coma–>death
Neuritis
inflammation of nerve or nerves
etiology of neuritis
–injury – compression, contusion
–infection (tetanus, tuberculosis), inflammation
–chemical poisoning (arsenic, lead), medication
–neoplasm or stress
symptoms of neuritis
- headaches
- hyperesthesia (hypersensitivity)
- paresthesia (numbness, tingling)
- dysesthesia (painful sensation)
- muscular atrophy of part supplied by affected nerve,
- paralysis
- lack of reflexes
Tetanus
acute, infectious, life-threatening bacterial disease that affects the nervous system,
Tetanus is caused by
toxin produced by Clostridium tetani–>toxin attaches to motor neurons
Tetanus results in
painful muscle contractions, particularly of jaw (lockjaw ) and neck muscles
Tetanus is found in
animal feces, spores in soil
Symptoms of Tetanus
- painful, uncontrolled contractions of skeletal muscles
- high fever
- tachycardia (faster heartbeat)
- dysphagia (difficulty swallowing)
- intense pain
Epiliepsy
chronic neurogenic disease marked by sudden alterations in consciousness & convulsions
•a temporary lack of oxygen to vital brain centers
•recurrent seizures of unknown origin
2 types of epilepsy
Petit mal seizure = small
•Loss of consciousness, usually for few seconds
•No memory of the seizure, no complications
Grand mal seizure = large
•Loss of consciousness, muscle rigidity, spasms of face, neck, arms, legs, person will thrash about
epilepsy may result in
–cyanosis, breathing difficulty, tongue may be bitten, excess salivation, bloody froth or saliva
•Generally lasts for a few minutes
Predisposing factors of epilepsy
- Congenital abnormality of blood vessels in the brain
* Some disorders which block blood flow to the brain
CNS: Degenerative Diseases
- Alzheimer’s disease
- Amyotrophic lateral sclerosis
- Parkinson’s syndrome
- Multiple sclerosis
- Creutzfeldt - Jakob Disease
Alzheimer’s Disease
progressive & fatal brain disease,
•named for German physician Alois Alzheimer
•most common type of dementia
alzheimer’s disease is due to
formation of protein plaques, or tangles of nerve fibers in the brain that interfere with communication between nerve cells in the brain
Symptoms of Alzheimer’s Disease
- amnesia, impaired recognition, forgetfulness
- emotional upsets, confusion, mood changes,
- inability to concentrate, inability to complete simple tasks
- irritability, agitation, restlessness , depression, hostility
- motor disturbances, muscle rigidity, paralysis, apraxia (skilled movements)
Amyotrophic Lateral Sclerosis
Lou Gehrig’s disease
•destroys both: upper & lower motor neurons (brain & spinal cord)
Symptoms of ALS
•cramps, muscle weakness, uncontrollable twitching
Parkinson’s Syndrome
degenerative disorder of the central nervous system basal ganglia (nuclei) causing faulty nerve signal transmission
•insufficient dopamine
Causes of Parkinson’s Syndrome
- environmental toxins, no hereditary basis
- trauma (often affect boxers),
- tumors, prior infections, drugs, atherosclerosis (more common)
Symptoms of Parkinson’s Syndrome
- “tremors at rest”, rigidity of muscles, weakness of muscles, a forward lean
- slurred speech
- digestive and urinary difficulty
- hypotension (low blood pressure)
- In late stages: depression & dementia
Multiple Sclerosis
degeneration of the brain and spinal cord
•autoimmune disease - body attacks its own myelin
Multiple Sclerosis is characterized by
remissions and relapses and by the presence of sclerotic (hardening ) patches of demyelination
•softening of the spinal cord
•ages 25-40
Symptoms of Multiple Sclerosis
•Loss of coordination (1st symptom) •Optic disturbances •Tremors •disturbance in neural pathways –local anesthesia and paralysis •Respiratory problems •Loss of bowel and bladder control •Paralysis to the limbs
Creutzfeldt-Jakob Disease
degenerative neurological disorder of the brain
- very rare
- incurable
- rapid development (6-12 months)
- possibly from eating infected beef
cause of Creutzfeldt-Jakob Disease
protein called a prion that folds abnormally, which affects its function
Symptoms of Creutzfeldt-Jakob Disease
–personality changes, hallucinations,
–muscle twitching & stiffness
–lack of coordination
–speech impairment
CNS: Congenital Disorders
Cerebral palsy
Microcephaly* - small brain
•occurs with Down’s Syndrome
Anencephaly* - no brain
Cerebral Palsy
motor disturbance present at birth, usually due to a congenital birth defect or birth trauma
-non-progressive, little or no mental damage
symptoms of cerebral palsy
•limited motor skills, speech difficulties, learning disabilities
CNS: Genetic Disorders
caused by gene mutations – permanent changes in the genetic material
–due to radiation, chemicals, viruses
autosomal dominant disorders
- Neurofibromatosis
- Huntington’s Disease
Neurofibromatosis
disorder of a particular tumor suppressor gene
–peripheral nerve benign tumor
–arise from fibrous coverings of nerves
Huntington’s Disease
neurological disorder that leads to progressive degeneration of brain cells–>loss of psychomotor control of body
autosomal recessive disorders
Tay Sachs disease=lack of enzyme (hexosaminidase A) that helps break down a lipid found in nervous tissue called ganglioside
Tay Sachs Disease is most common in
certain Eastern European Jewish population
Gliomas
tumors originating in neuroglia of the brain or spinal cord
•most common type of brain tumor
•categorized by location & type of cells that originated the tumor
Astrocytomas
astrocytes, in brain or spinal cord
–most common type of childhood brain tumor
–in cerebellum
Meningioma
- tumor of meninges (dura)
- slow growing, most common in 40 & 50 year-old people
- in cerebral hemispheres, under the skull
- usually are separate from the brain & can be removed entirely during surgery
- Can recur & certain types can be malignant
Retinoblastoma
malignant tumor of one or both eyes •retinal cells •Develops during infancy or early childhood •Usually diagnosed by two years of age •Probably hereditary
