Neuro exam #1 Flashcards
Excitability
ability to generate an impulse
Conductivity
ability to transmit an impulse within itself
Influence
ability to influence another neuron
Afferent
towards the CNS (ascending)
Efferent
away from the CNS
Interneruron
transmitting from one neuron to another
Oligodendrocytes
make myelin sheath
Astrocytes
accumulate where neurons have been damaged feed blood brain barrier
Ependymal cells
secretion and regulation of CSF
Microglia
remove waste
Nerve regeneration
damaged nerves try to regrow CNS: limited ability PNS: can regenerate
Nerve impulse conduction
travels by the electrical transmission along the axon and the chemical transition between neurons (synapse) until impulse reaches its destination Resting: K high, Na low Depolarization: Na channels open and become high in cell Repolarization: K channels open, slowly enter, K rises and become high in cell again
Action potential
impulse reaches the end of the nerve fiber then transmitted across the junction between nerve cells at the synapse chemical interaction generates another action potential in the next neuron. Repeated until the impulse reaches its destination or end organ
Saltatory conduction
-Nerve conduction of the myelinated cells -action potential jumps from 1 node of Ranvier to the next
Nodes of Ranvier
gaps in myelin sheath
Synapse
Junction where nerve impulse is transmitted from one neuron to another neuron
Synaptic Transmission
presynaptic knob: release impulse synaptic cleft: space between neurons neurontransmitter: chemical involved in impulse from one neuron to another receptor site: next neuron picks up impulse (neurontransmitter: have excitatory or inhibitory effects)
CNS consists of…
brain and spinal cord
PNS….
12 pairs of cranial nerves 31 pairs of spinal nerves
Foramen Magnum
largest hole in the skull. where the spinal cord enters and exits
Meninges
3 protective membranes surround the brain and spinal cord (epidural space: btwn skull and dura) Dura: outer layer. thickest and toughest. (subdural space: below dura. btwn dura and arach) Arachnoid: Middle layer. thinner and more delicate (subarachnoid space: CSF flows here) Pia mater: innermost layer. Mush-like and very vascular.
Falx cerebri
dural fold separates the 2 cerebral hemispheres
Tentoriun cerebelli
-double dura layer folds btwn cerebral hemispheres and cerebellum. -allow for expansion of the one structure w/o altering another.
CSF
clear, colorless, odorless fluid -fills ventricles and subarachnoid space -shock absorber, cushions brain and spinal cord from injury -consists of nutrients (water, protein, O2 , CO2, Na, K, Cl, glucose)- NO RBCs.
Choroids plexus
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Brain requires how much of the body’s oxygen and glucose?
25%
Venous drainage
-exit via 2 vascular channels created by the dural layers called the dural sinuses -empty into jugular veins. NO VALVES. work by gravity.
Anterior circulation
from the carotid (branch into internal and external carotid)
Posterior circulation
subclavian and basilar artery. Basilar artery: vertebral arteries unite to become this in posterior circulation.
Circle of Willis
allows blood to circulates from one hemisphere to the other. -protects from changes in pressure or occlusion. -main components are the basilar artery and internal carotids.
Autoregulation
brain can self regulate blood supply -does this by changes of blood vessel diameter (independent of systemic BP)
Blood brain barrier
-barrier between blood capillaries and brain tissue -made up of tight capillaries and astrocytes -protects brain from potentially damaging agents like toxins -lipid soluble
Gyrus
folds on surface of the brain
Fissure
deep, predictable separation of the cerebral hemispheres
Cerebrum
largest part of the brain associated with sensory, motor, and higher mental functions
Cerebral cortex
outer layer of the brain (white and gray matter)
Frontal lobe
contra-lateral (control opp. sides) motor function, memory, cog. func, judgement, Broc’s area
Broca’s area
-Necessary for expressive speech. -formation of the spoken word. — damage causes difficulty forming words –cerebral dominancy is in the left frontal lobe
Parietal lobe
sensory, spacial awareness, body awareness
Temporal lobe
auditory (wernicke’s area)
Wernicke’s area
in charge of understanding written and spoken speech (damage is receptive aphasia)
Occiptial Lobe
area for vision and visual association
Basal ganglia
initiation, execution, and completion of voluntary and automatic movement.
Diencephalons
area in the brain just above the brainstem -contains the thalamus and hypothalamus
Thalamus
relay station for all sensation
Hypothalamus
regulates 1) autonomic NS (involuntary body functions) and 2) endocrine (pit. secretion, temp control, fluid balance, repro, metab, hunger sensor that controls appetite)
Limbic system
responsible for primal human function (feeding, sex, and emotions)
Brain stem
-medulla oblongata, pons, and midbrain -connects spinal cord with cerebrum with cerebellum -contains ascending and descending pathways -attachment for CN 3 thru 12 -responsible for reflexes : cough, hiccup, swallow, and vom)
Medulla oblongata
primary rhythm center (repsirations, vasomotor functions like heart rate/function, BP)
Reticular formation
neurons control the sleep-wake cycle
Cerebellum
responsible for coordination of motor function, balance, spine smooth movements
Spinal cord
-mass of nerve fibers -extends from C1 to L1
Cauda equina
horse tail look at the bottom of the spinal cord. (non-myelinated)
Spinal cord matter
“H” wider arms are ventral, motor. send messages out thinner posterior and sensory and messages come in
Ascending tracts
Carries sensory input dorsal column: (posterior) enters at spinal cord crosses at medulla and stops in thalamus and terminates in cerebral cortex. (position, movement, deep touch, kinesthesia) Spinocerebellar: enters spinal cord and straight to cerebellum. No crossing. (muscle tension, body position for coordination of movement) Spinothalmic: enters spinal cord and crosses to the opposite terminates in the thalmus. (pain and temp sensations)
Descending tracts
carry motor messages corticospinal: cortex frontal lobe crosses the medulla then descends into spinal cord (voluntary motor function) Upper motor neurons: located in cerebral cortex. lesions cause weakness, paralysis, hyperreflexia Lower motor neurons: connect to CNS. lesions cause weakness, paralysis, flaccidity, and hyporeflexia
Reflexes
involuntary response to a stimulus monosynaptic reflex: receptor organ, sensory neuron, info processed in the spinal cord, motor neuron.
CN #1
-Olfactory -smell -identify familial odors (each nostril individually with eyes closed)
CN #2
Optic (sensory only) -vision/peripheral vision -use snellen chart -p. vision- look at examiners nose and identify when you see finger with one eye covered
CN #3, #4, #6
3: oculomotor 4: trochlear 6: abducens #3 function: eye movement, eyelid elevation, and pupil constriction. #4: eye movement test by have the pt follow the examiners finger while making an “N” and pen light for pupil constriction
CN #5
Trigeminal (sens & motor) function: facial sensation and chewing test: cotton ball on forhead, cheeks, jaw with eyes closed. clench teeth and open jaw against resistance
CN #7
Facial (sens & motor) function: taste and facial expression test: taste sugar and salt on tongue. smile, puff out cheeks, close eyes and examiner try to open.
CN #8
Acoustic or vestibulocochlear (sens only) function: hearing and equilibrium test: tuning fork, watch ticking, rustle fingers, whisper test. ask to walk in a straight line
CN #9 & #10
9: glossopharyngeal #10: vagus function: 9: taste on posterior tongue, pharynx, larynx. gag and swallow. 10: sensation of pharynx and larynx, smooth muscle sensation. gag and swallow. test: gag reflex with tongue depressor or make “k” sound. and ask to swallow.
CN #11
Spinal accessory (motor) function: sternocladi, trap, and neck muscles test: shrug shoulders and turn head (against resistance)
CN #12
Hypoglossal (motor) function: tongue muscle test: stick out tongue and see if it’s midline and not deviated.
Autonomic nervous system
effects voluntary function of cardiac, smooth muscles, and glands -maintain a relatively stable environment for the body. -Sympathetic: fight or flight -Parasympathetic: rest and digest
Roots of spinal nerves
dorsal root: sensory ventral root: motor fibers detach from ventral root dermatomes: area of skin innervated by a specific sensory spinal nerve root myotome: muscle group innervated by a single motor fiber
Auditory system and functions
-reception and perception of sound -hearing and balance -essential for normal development of speech
Peripheral auditory system
-external and middle ear: receiving and perceiving sound -inner ear: sending info to brain for hearing and equilibrium
Central auditory system
acoustic nerve and auditory cortex
Pinna
(external ear) -connective tissue/cartilage -collect and transmit sound waves to the tymp. mem.
External auditory canal
lined with fine hairs, sebaceous glands, and cerumenous glands. -outer portion-more course. inner portion- more sensitive.
Cerumen
-earwax -protective, works to kill bacteria, help keep debris from entering. -ear’s defense.
Middle ear
located in the temporal bone. -inaccessible for exam bc eardrum is blocking it -connected to the nasopharynx by the eustachian tube
Eardrum
(tympanic membrane) -shiny, translucent, pearly gray -slightly concave -sound waves conducted by the tympanic membrane then ossicles
Eustachian tube
-helps equalize pressure -helps prevent tympanic membrane from rupturing -if blocked, ability to equalize pressure is down
Ossicles (3)
malleus, incus, and stapies
Inner ear
-includes the vestibule, cochlea, semicircular canals, membranous labyrinth, bony labyrinth
Bony labyrinth
(bony canals) -contain fluid that protects and cushions the organs of hearing and of balance
Vestibule
(bony chamber) *************
Semicircular canals
-sensory organs that help with equilibrium -oriented in 3 different planes -stimulated by how fast and what direction we move
Cochlea
snail shape *****************
Organ of corti
(in the cochlea) -tiny hair cells that respond to stimulation. transmits into nerve impulse
Vestibulocochlear nerve
1) vestibule portion: receives impulses from semicircular canals and allows brain to send signals to relax or contract muscles and maintain balance 2) cochlear portion: receives impulses from cochlea so brain can interpret sound
Air conduction
*******************
Bone conduction
-sound waves directly from the skull to cause fluid waves in the vestibule. bypasses external and inner ear
Equilibrium
-controlled by the vestibule and semicircular canals -as we move, fluid in the canals move -in absence if cues (visual or tactile) we would still be able to determine position bc of the semi-circular canals firing
Dynamic
maintenance of body position when we are moving
Auditory system and functions
-reception and perception of sound -hearing and balance -essential for normal development of speech
Peripheral auditory system
-external and middle ear: receiving and perceiving sound -inner ear: sending info to brain for hearing and equilibrium
Central auditory system
acoustic nerve and auditory cortex
Static equilibrium
orientation of body to ground and essential to maintaining posture
Nystagmus
Vertigo
sense that a person or objects around you are moving or spinning
-asked to continue activities in small amounts and it should eventually go away. (habituation)
Conductive hearing loss
Sensorineural hearing loss
- damage inner ear (cochlea, hair cells, vestibule)
- damage to acoustic nerve or temporal lobe.
- can have profound damage
Functional hearing loss
- result of emotional disturbance
- nothing is actually wrong with the ears
Prebycusis
age-related hearing loss
- eardrum thickens: decrease conduction
- hair and cerumen: (more) block sound wave coming thru
- ossicles: calcify/harden
- hair cells: damaged bc of noise exposure or sickness etc.
Tinnitus
When examining the ear
Whisper test
(gross hearing test)
- whisper a phrase 1-2 ft. away from pt (stand to side and out of sight), occlude one ear, and increase volume until they can hear
- ask to repeat sentence back
Rinne Test
Weber Test
Audiometry
- diagnostic instrument for evaluating hearing
- single most important test for hearing loss
- sound proof room using different pitches and tones: raise hand when you hear the beep.
Electronstagmography
irrigate the ear and evaluate eye movement
Rotary chair Test or Sinusoidal harmonic acceleration
-sit in a chair that spins at a set rate.
Platform posturography
- postural control (static equilibrium)
- stand on moveable platform surrounded by screens
Nursing care for Vestibular function and equilibrium tests
Otologist
specialize in tx & dx
-perform surgery
Otolaryngologist
ENT
perform surgery
Audiologist
Instilling eardrops
- identify pt and med, check dropper
- administer drops at room temp. (if cold could cause dizziness)
- lie on unaffected side
- pull ear up and back to straighten ear canal
- support your hand on pts head to stabilize
- remain on side for 2-10 mins (check med to see)
- use cotton ball to help hold the medication in
Ear irrigation
- purpose is to clean canal, soften and remove impacted wax or dislodge a foreign body
- position pt toward you to help drain
- emesis basin to catch drainage
- clean the out auricle and auditory meatus before test
- straighten auditory canal
- insert syringe tip: point upward, above obstruction to get passed it.
- may cause vertigo, nausea, otitis,
Do NOT irrigate if….
Ear Wicks
Do NOT use Ear wicks for what pts….?
children and confused people
-bc they might push them in further.
Orbit
union of cranial and facial bones
-protective socket for eye
Lashes and Brows
Lashes and Brows
Palpebrae
Conjunctiva
- thin transparent mucous membranes
- secretes mucous and oil to keep cornea moist
- help cornea stay clear and free of friction
palpebral conjunctiva: lines eyelid
bulbar conjunctiva: line the sclera
Lacrimal gland
- located above the outer canthus of the eye
- tear flow from outer canthus to inner canthus
- function: produces tears for moistening, provide O2, provide a smooth refractive surface for cornea, washes out foreign bodies, and are bacteriostatic
Puncta/Punctum
Vision
- light is processed by the eye and interpreted by the brain
- pathway: light passes thru the cornea through an opening called the pupil. then thru the lens thru the gel-like fluid (vitreous humor) of the posterior cavity focused on the retina. the light is then converted into a nerve impulse and carries the message to the brain thru the optic nerve
Extrinsic occular muscles
Intrinsic occular muscles
(inside the eye)
- ciliary muscles: in ciliary body. Connected to the lens so they are responsible for change of lens shape and focusing light on the retina
- sphincter and dilator iris muscles: increase or decrease the size of the iris therefore the pupil size.
Sclera
Cornea
Iris
Pupil
Choroid
Ciliary body
Lens
Retina
Rods
Cones
Macula
Fovea Centralis
- center of the macula
- most sensitive area
- has densely packed cones (no rods)
- responsible for sharpest visual acuity
Optic disc
-physiologic depression or cup point where optic nerve exits and blood supply enters
Posterior or vitreous cavity of the eye
- behind the lens filled with vitreous humor
- helps give shape to the eye
- both humors help maintain pressure in the eye
Physiology of the eye
Optic chiasm
fibers of each eye cross to the other side
- left optic tract: fibers from the left field of vision of both eyes travel to the right occipital cortex
- right optic tract: same but with right field of vision
Ptosis
eyelid drooping
Anisocoria
Exopthalmos
Enopthalmos
sunken appearance
OS
left eye
OD
right eye
OU
both eyes
Jaegar chart
- tests near vision
- regularly used for people 40 and over
Refractometry
multiple lens mounted on a wheel and say which you can see better with
corneal light reflex
Six cardinal positions of gaze
Confrontation test
-stand opposite the examiner and say how many fingers they are holding up or when they could see the examiners fingers
Pupillary reflex
when a pen light is on eye and get brisk pupil constriction
direct constriction: occurs in the eye you shine the light in
consensual constriction: pupil of the other eye contricts
Pupillary accommodation
when you focus on something far away and the pupils constrict
Opthalmoscope
magnification, focus, proper use, retina, optic nerve
- use your right eye, and examine their right eye, come in from the right
- in a darkened room
Evaluation of optic disc, retina, and macula
Red reflex
Intraocular pressure
-need for normal vision
-10-21 mmHg = normal pressure in the eye
(glaucoma increases intraoc. pressure)
Florescein angiography
Optical coherence tomography
Ishihara test
7 danger signals for eyes
redness, pain or photophobia, visual disturbances, crossing of the eyes, growths, discharge crusting or tearing
Opthamologist
Optometrist
Optician
Geriatric eye probs
- eyelids: tissue atrophy, lower lid droop, dryness
- arcus senilis: milky white/yellow ring around the iris. does not effect vision. result of cholesterol deposits
- sclera color changes: may become yellow
- decreased lacrimal production
Eye Solutions
- easily instilled
- rarely cause skin rxns
- bc they are thin they don’t stay in contact with the eye long (apply more freq)
- discard after 3 months
- pt tilt head back and look at the ceiling. pull lower lid down a little and come from the side. place drops on lower conjunctiva
- keep eyes closed 1-2 mins and wait 5-10 mins til next med
Eye ointments
- thicker so they stay in contact with the eye longer
- cause freq. skin irritations
- blurred vision bc of ointment
- instill same as eye drops. put from inner canthus to the outer canthus
