7. Nervuos System Flashcards
neurologist
physician who specializes in treating diseases/disorders of the nervous system
neurology
study of nervous system and it’s disorders
neurosurgery
any surgery involving the brain, spinal cord, or peripheral nerves
neurosurgeon
physician who specializes in surgery of the brain, spinal cord, or peripheral nerves
2 divisions of nervous system
1) central nervous system (CNS)
2) peripheral nervous system (PNS)
central nervous system (CNS)
- central part of body
- brain and spinal cord
- processing and storying sensory and motor information
peripheral nervous system (PNS)
- cranial and spinal NERVES that come off spinal cord
- part of nervous system outside the CNS
- 12 pairs of cranial nerves and 31 pairs of spinal nerves
- somatic and automatic nervous system part of PNS
- responsible for transmitting sensory and motor impulses back and forth between CNS and rest of body
3 kinds of nerves
1) afferent
2) interneurons
3) efferent
afferent nerves
- sensory nerves
- carry impulses from body to CNS
- ex. touch something hot - afferent nerves send signal to efferent nerves to move hand
efferent nerves
- motor nerves
- carry impulses from CNS to muscles and glands causing target organs to do something in response to the commands recieved
- ex. tell muscles to remove hand from hot surface
2 systems PNS is broken down into
1) somatic nervous system
2) autonomic nervous system
somatic nervous system
- part of PNS
- voluntary
- controls skeletal muscles
autonomic nervous system
- part of PNS
- involuntary
- controls smooth/visceral muscles and glands and cardiac muscle in response to command from CNS
- contain sympathetic and parasympathetic nerves
sympathetic nerves
- part of autonomic system
- regulate essential involuntary body functions
- increases heart rate and blood pressure
- responds to “fight-or-flight response”
- ex. in car crash body fills with adrenaline
parasympathetic nerves
- part of autonomic nervous system
- regulate essential involuntary body functions
- lower heart rate and lower blood pressure
- serves as a complement to SNS
- return body to a more restful (normal) state
2 main types of nerves in tissue cells
1) neurons
2) neuroglia
neuroglia
- special type of connective tissue
- provides support for nervous system and neurons
- do not conduct implulses
- protect nervous system through phagocytosis
phagocytosis
- engulf and digest any unwanted substances
* a function of neuroglia
neurons
- nerves
- functional unit of the nervous system
- contains cell body, axon, and 1+ dendrites
- not continuous with one another; small space between axon of one neuron and the dendrite of another neuron
3 basic parts of neurons
1) cell body
2) axon
3) one or more dendrites
cell body
structure that contains nucleus and cytoplasm
axon
- single, slender projection that extends from cell body
* conduct impulses away from cell body
dendrite
- brings in impulses
- feelers
- projection that extends from nerve cell body
- receives impulses and conducts them on to the cell body
myelin sheath
- covering of some neurons
- helps speed the transmission of an impulse
- protection sheath that covers the axons of many neurons in the body
white matter
- axons covered by myelin sheath
* myelinated axons
gray matter
axons not covered by myelin sheath
synapse
- the space between 2 neurons
- where impulses cross
- synaptic cleft
neurotransmitters
- chemicals released from one neuron through the synapse to another
- chemical substance that activates or inhibits the transmission of nerve impulses at synapses
- excitatory and inhibitory
2 examples of neurotransmitters
1) excitatory
2) inhibitory
excitatory
- excites nervous system
* ex. caffeine, cocaine
inhibitory
- inhibits nervous system
* ex. anesthesia, alcohol
4 types of neuroglia
1) astrocytes
2) microglia
3) ependymal cells
4) oligodendrocytes
astrocytes
– type of neuroglia • most numerous • star-shaped with long legs • only in CNS • around brains capillaries and form a tight sheath called blood-brain barrier
blood-brain barrier
- tight sheath made of astrocytes and wall of capillaries
* protects the brain from harmful substances in the blood
microglia
- type of neuroglia
- branches extending from cell body; lots of legs
- digest debris and pathogens (garbagemen)
- multiply when cells injured and go to damaged areas
- small interstitial cells with many slender branches off body
ependymal cells
- lines cavities (ventricles) in the brain and spinal cord
- surrounds cerebrospinal fluid
- spaces in brain and spinal cord where you find cerebrospinal fluid
cerebrospinal fluid (CSF)
- the fluid flowing through the brain and around the spinal cord
- protects brain/spinal cord from physical blow or impact
- surrounded by ependymal cells
oligodendrocytes
- covers axons to form myelin sheath
- speeds the conduction of nerve impulses in CNS
- found in intertitial nervous
- processes of oligodendrocytes fan out from cell body and coil around the axons of some neurons to form myelin sheath
3 meninges
• 3 layers of protective membranes that cover the CNS
1) pia mater
2) arachnoid membrane
3) dura mater
pia mater
- innermost layer of meninges
- tightly bound to the surface of the brain and spinal cord
- tender
arachnoid membrane
- middle layer of meninges
- resembles spider web
- where you find subarachnoid space where cerebrospinal fluid is found
subarachnoid space
- located under the arachnoid membrane
* holds cerebrospinal fluid (CSF)
cerebrospinal fluid (CSF)
- found in subarachnoid space
- cusions/protects brain and spinal cord
- shock absorber
- provides protection and nutrients
- flows in and around the organs of the CNS
dura mater
- outermost layer of meninges
- tough, white connective tissue
- thicker, stronger
brain
- one of the largest organ in adults (3 lbs)
- brain grows rapidly in first 9 yrs; reaching full size at 18 yrs
- 4 major divisions: cerebrum, cerebellum, diencephalon, and brain stem
4 parts of the brain
1) cerebrum
2) cerebellum
3) diencephalon
4) brain stem
cerebrum
- largest part of the brain
- contains gyri and sulci
- uppermost portion of brain
- controls concisouslness, memory, senstation, emotions, and voluntary muscles
gyri (gyrus - singular)
- elevations/hills on surface of cerebrum
* gives the appearance of encased sausage folded upon itself many times
sulci (sulcus-singular)
• grooves/valleys on the cerebrum
cerebellum
- behind the brain stem; attached
- creates balance
- looks like walnut
- maintains muscle tone and coordinating normal movement and balance
brain stem
- connects brain to spinal cord
- consists of midbrain, pons, and medulla oblangata
- serves as a pathway for conduction of impulses between brain and spinal cord
spinal cord
- pathway for impulses traveling to and from the brain
* protected by the CSF, 3 layers of meninges, and the bony encasement of the cervical, thoracic, and lumbar vertebrae
acetylcholine
- neurotransmitter
- (ACH = common)
- chemical substance that helps the transmission of nerve impuses from one nerve to another
- it has a stimulant/excitatory or depressant/inhibiting effect on parts of the body
anasthesia
without feeling/sensation
aneurysm
- weakening and dilation of the wall of an artery
- walls ballon and might rupture
- rupture = death
- commonly found in abdominal aortic aneurism (AAA) - top of heart and down to abdomen
aphasia
- inability to communicate
- due to injury or disease of the brain
- inability to communicate through speech, writing, or signs
- may be cause by stroke or cerebral hemorrhag
aphasia/asphagia
- ’s’ = nervous system; speaking
* ‘g’ = digesting system; swallowing
astrocytoma
- tumor of brain or spinal cord
* made of astrocytes
ataxia
- without muscle coordination
- drunk = ataxic gait
- due to neurological damage; damage of spinal cord or spinal cord nerve
bradykinesia
abnormally slow movement
Brudzinski’s sign
- positive sign of meningitis
- involuntary flexion of the arm, hip, and knee, when the patient’s neck is passively flexed
- the patient lays down and lifts head –> shoulders/knees flex
burr hole
- holes drilled into skull using drill
* relieve pressure or drain fluids due to inter-cranial swelling
cauda equina
- lower end of spinal cord and roots of the spinal nerves
- looks like a horse’s tail
- nerves come off spinal cord
cephalalgia
headache
Cheyne-Stokes respiration
- abnormal breathing pattern
- apnea followed by deep rapid breathing
- person is getting ready to die
dementia
progressive, irreversible deteriorating memory
deficit
- any deficiency or variation of the normal
* ex. neurological deficit - cerebrovascular accident (CVA)
diplopia
double vision
dysphasia
difficult speech
embolism
- blood clot (embolus) becomes lodged in a blood vessel
- obstructs flow of blood
- pulmonary embolism = blood clot in lower leg travels to lung; blood flow to lungs blocked; death
gait
style of walking
hemiparesis
- slight or partial paralysis of one half of the body (L or R sides)
- slight paralyis, tingling, numbness
hemiplegia
paralysis of one half of the body (L or R sides)
Kerning’s sign
- positive sign of meningitis
- inability to extend leg completely when leg is at right angle to body when person is sitting/laying down
- patient lays down, knee up, doctor tries to extend leg = pain = meningitis
lethargy
a state of being sluggish
lethargic
sluggish/tired
narcolepsy
- uncontrolled, sudden attacks of sleep
* take meds to control
nuchal rigidity
- stiff neck
* seen in patients with meningitis
neuritis
inflammation of nerve
occlusion
blockage
palliative
- soothing
- docs can’t do anything to cure; just reduce symptoms
- ex. palliative chemotherapy - can’t prevent patient from dying from cancer; just reduce symptoms and pain
parasthesia
- numbness or tingling
* ex. carpal tunnel; may be in fingers due to nerve damage
radiculectomy/rhizotomy
surgical resection/removal of a spinal nerve root to relieve pain
sciatica
- inflammation of the sciatic nerve
* pain along course of nerve, radiating through the thigh and down the back of the leg
shunt
- tube to redirect fluid
- redirect body fluid from one cavity/vessel to another
- VP shunt - from ventricle to brain to abdominal cavity to drain CSF
thrombosis
- clot develops in blood vessel
- DVT - deep vein thrombosis - clot deep in veins of the legs
- life threatening if it becomes embolysim
ventricle
hollow space in brain filled with CSF
Bell’s palsy
- temporary or permanent paralysis of the muscles on one side of the face
- can’t control muscles
- may come and go
- due to face trauma, unknown infection, or a tumor pressing on facial nerves
- symptoms = drooling, can’t close eye, can’t regulate syliva
- treatment = nmassage, warm/moist heat, facial exercises
carpal tunnel syndrom
- pinching/compression of the median nerve within the carpal tunnel
- due to inflammation of the tendons
- caused by repetitious overuse of the fingers, hands and wrists
- surgery - cut tendon/ligament to remove pressure on nerves
- good posture helps prevent this
2 carpal tunnel tests
1) Tinel’s sign
2) Phalen’s test
Tinel’s sign
• carpal tunnel test
* doc will tap along forearm wrist over the median nerve
• positive test = patient experiences pain, tingling, or numbness over wrist and or in median nerve
Phalen’s test
- carpal tunnel test
- raise arms and put backside of hands together so fingers point toward floor
- causes wrists to fully flex and may compress median nerve and reproduce symptoms
- position is held for 60 seconds
- Phalen’s test may be more specific for carpal tunnel diagnosis than Tinel’s
cerebral palsy (CP)
- congenital (at birth) brain damage
- lack of voluntary muscles
- due to lack of oxygen at birth (baby didn’t get enough oxygen during delivery)
- brain damage permanent but not progressive
- baby tone may be floppy
- symptoms: slow development, communication problems, seizures, stiffness
degenerative disk disease (DDD)
- deterioration of the intervertebral disks
- causes lots of pain in vertrebrae
- due to constant motion and wear of disks
grand mal seizures
- tonic-clonic seizure
- sudden loss of consciousness (LOC)
- involuntary muscle contraction and rigid body extension (patient convulses)
- epileptic seizure
- most common seizure in adults and children
petit mal seizures
- small seizures
- loss of consciousness (LOC) last for a few seconds
- in a daze
- no convulsions
- seizure often goes unnoticed by the individual
Guillain-Barre syndrom
- acute polyneuritis (inflammation of many nerves)
- myelin sheaths in PNS are destroyed
- usually follows viral gastrointestinal or respiratory infection
- decreased nerve impluses; loss of reflex response, and sudden muscle weakness
polyneuritis
inflammation of many nerves
hydrocephalus
- abnormal increase in CSF in ventricles
- heads of body become swelled up
- increased head circumference in infant with open fontanel
- congenital (at birth) disorder
- put in shunt to redirect CSF fluid
meningitis
- inflammation of the meninges
- bacterial (more severe) or viral infection
- bacteria enters meninges by way of bloodstream from infection or wound in another part of body
- swelling of brain tissue, congestion in blood, circulation of CSF, and formation of clums
- inter-cranial pressure
bacterial vs. viral infections
- bacterial are harder to treat; longer to recover
* viral takes body 7 days to get rid of virus
multiple sclerosis (MS)
- degenerative inflammatory disease of the CNS attacking the myelin sheath
- leaves sheath sclerosed (hardened) or scarred
- autoimmune disease - body attacks itself
- mostly women between 20-40
myasthenia gravis
- chronic progressive neuromuscular disorder causing sever muscle weakness (atrophy)
- autoimmune - antibodies attaching ACH receptors
- ex. droopy eye
Babinski’s reflex
- causes dorsiflexion when the sole of the foot is stroked
- test if there’s disease of upper motor neurons
- Babinski’s reflex reaction is normal in newborns, but abnormal in adults and children
- normal reaction is bottom of foot is stroked and you jerk away
electroencephalogram (EEG)
- measures electrical activity in the brain
* electrodes placed on scalp
Rhomberg test
- used to evaluate the cerebellar function and balance
- testing balance
- person stands with feet goether and hands at side and at equilibrium. Step 1 = close eyes –> can you maintain balance? Step 2 = life hands to shoulder height and close eyes –> can you stand without hands drifting downward? Complete both = cerebellar function intact
lumbar puncture
- use hollow needle to extract CSF
- puncture between 3rd and 4th lumbar vertebrae
- below spinal cord (which stops at L2)
- patient lies forward or on side to open up vertebrae
- can diagnose many disorders
laminectomy
- surgical removal of bony arches from one or more vertebrae
* to relieve pressure on spinal cord
CT
- computerized tomography
* aka CAT scan (computerized akial tomography)
MRI
- magnetic resonance imagery
* take magnet and look at bones and organs
PET
positron emission tomography
TENS
- transcutaneous electrical nerve stimulation
* pain, sever back pian, electrical current to area to help relieve pain by tricking body
TIA
- transient ischemia attack
- mini strokes
- cardiac arteries in neck become built up
