Neuro Flashcards
CNS is composed of
brain and spinal cord
PNS is composed of
12 pairs of cranial nerves
31 pairs of spinal nerves and all of their branches
Cerebral cortex is the center for
our highest functions - governs thought, memory, reasoning, sensation, voluntary movement
The left hemisphere of the Cerebral cortex dominant in __ percent of people
95%
each hemisphere is divided into how many lobes?
4
what are the 4 lobes of each hemisphere of the cerebral cortex?
- frontal
- occipital
- parietal
- temporal
Brokus area of the frontal lobe mediates ___. When it is damaged in the dominant hemisphere, ___ occurs.
motor speech; expressive aphasia (the person cannot talk (they understand language and know what they want to say but when they try to talk it comes out garbled)
precentral gyrus initiates
voluntary movement
postcentral gyrus in the parietal lobe is the primary center for
sensation
Werneke’s area in the temporal lobe is associated with ___. When this is damaged in the dominant hemisphere, the person gets ___.
language comprehension; receptive aphasia - the person hears sound but it has no meaning, like hearing a foreign language
the occipital lobe is the primary
visual receptor center
Basal ganglia controls
automatic associated movements of the body (i.e. when walking arm swing alternates with legs)
subcortical motor system which we call the
extrapyramidal system
Thalamus is the main relay station for the
CNS; sensory pathways of spinal cord and brainstem form synapses here on the way to the cortex
Hypothalamus is a major control center that regulates
vital functions: temperature, heart rate, blood pressure control, sleep center, anterior and posterior pituitary gland regulator, coordinator of autonomic nervous system activity and emotional status
Cerebellum is the coiled structure under the occipital lobe which is concerned with
motor coordination of voluntary moments, and equilibrium and muscle tone
Cerebellum does NOT initiative movement but it
coordinates and smooths movements - ex. playing piano, swimming, juggling — it adjust and corrects our voluntary movements but it operates entirely below conscious level
brainstem, 3 parts
central core of the brain that consists mostly of neural fibers, 3 parts: midbrain, ponds, medulla
midbrain
most anterior part, still has a basic tubular structure resembling spinal cord; merges into thalamus and hypothalamus, contains many motor neurons and tracts
ponds
enlarged area that contains ascending and descending fiber tracts
medulla
continuation of the spinal cord in the brain that contains all of our ascending and descending fiber tracts that connect brain and the spinal cord; has vital autonomic centers such as respiration, heart and GI function as well as some of nuclei for CN 8-12; this is where pyramidal decussation occurs (crossing over of motor fibers — i.e. stroke in right side of brain affects left side of body)
pyramidal decussation
crossing over of motor fibers — i.e. stroke in right side of brain affects left side of body
motor nerve fibers originate in the motor cortex, travel to the brainstem where they cross to the opposite side then pass down in the lateral column of the spinal cord
spinal cord is the long cylindrical structure about as round as your little finger that occupies the upper 2/3 of the vertebral canal. it’s the main highway for
all fiber tracts that connect brain to spinal nerves; it mediates our reflexes; its nerve cell bodies/gray matter are arranged in butterfly/H-shape with anterior and posterior horns
left cerebral cortex controls motor function to
right side of body and vice versa
2 particular pathways of CNS
corticospinal tract (pyramidal tract) extrapyramidal tract
10% of cortiospinal fibers do not cross - these descend in the
anterior column of the spinal cord
corticospinal fibers mediate our
voluntary movement (skilled, discreet, purposeful - like writing)
extrapyramidal tract includes
all the motor fibers originating in the motor cortex, or the ganglia, or the brainstem and spinal cord that are outside the pyramidal tract
extrapyramidal tract is a much more ___ motor system
primitive:
these subcortical fibers maintain muscle tone and gross body movements (like walking)
cerebellar system: coordinates our
movement, maintains equilibrium and helps maintain posture
sensation travels in the ___ fibers in the ___ nerve, then through the posterior or dorsal route, then into the spinal cord
afferent; peripheral
once at the spinal cord, sensation takes one of two tracts:
(1) spinalthalamic tract
(2) posterior or dorsal columns tract
spinalthalamic tract contains sensory fibers that transmit the sensation of
pain, temperature, and crude or light touch
posterior or dorsal columns tract conducts the sensation of
position sense, vibration, and localized touch
propioception
position sense–means that without looking you know where your body parts are in space and in relation to each other
stereognosis
without looking you can identify a familiar object by touch
some organs are absent from the brain map: heart, liver, spleen — you know you have one, but you have no felt image about it — pain originating in these organs is ___ because no felt images exist in which to have pain, so pain is felt by ___
referred; proxy
Upper motor neurons:
a complex of all the descending motor fibers that can influence/modify the lower motor neurons
they are located completely within the CNS
convey impulses for motor areas of the cerebral cortex to the lower motor neurons in the anterior horn cells of the spinal cord
upper motor neuron diseases
CVA, cerebral palsy, MS
Lower motor neurons are located mostly in the
PNS
examples: cranial nerves, spinal nerves of the PNS
lower motor neuron diseases:
spinal cord lesions, polio, ALS (lou gherigs)
in order for reflex arc to work, you have to have 5 components:
- intact sensory nerve (afferent)
- functional synapse in the cord
- intact motor nerve fiber (efferent)
- neuromuscular junction must be intact
- muscle has to be competent/working
5 types of reflexes in the reflex arc
deep tendon superficial reflexes (ex. corneal) abdominal reflexes visceral/organic reflexes (ex. pupillary response to light/accommodation) pathological/abnormal (ex. babinski)
reflexes are
involuntary, below level of conscious control, and permit quick reactions to potentially painful/damaging situations, also help body maintain balance and appropriate muscle tone
breakdown of the 31 pairs of spinal nerves
8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 from coccyx
sensory afferent fibers enter and exit through ___ routes, motor efferent go through the ___ routes
posterior/dorsal; anterior/ventral
dermatomes
circumscribed skin area that’s supplied mainly from 1 spinal cord segment through a particular spinal nerve — they overlap a bit, so that if one nerve is severed, most of the sensations can be transmitted by the one above or the one below
thumb, middle finger, 5th finger are each in the dermatomes of
C6, C7, C8
nipple is at the level of
T4
bellybutton is at
T10
groin is in the region of
L1
if someone comes in with numbness in leg, you know it’s lumbar or sacral nerve, but where you do a prick to see you would be able to identify that they have decreased sensation in
L4 or L5
people with Parkinson’s patients have Extrapyramidal sign that they
don’t move their arms (they festinate, festination)
knee reflex/lumbar reflex is
2, 3, or 4
brachial radialis is cervical
5, 6 (so is biceps)
triceps is cervical
6, 7
benign essential tremors
people may have when they go to do something and you can put a piece of paper on their hand and watch the paper move — these tend to run in families, can be called familial tremors, are helped by alcohol and beta-blockers
intention tremors
when someone stretches out their arm to touch something in the distance - what Muhammed Ali has
Obtunded LOC
patient that opens their eyes and looks at you, but responds slowly and maybe somewhat confused. Interest in environment is also decreased
Stupor
arouses from sleep only after painful stimulation (rub on sternal area, squeezing of a very deep muscle)
Comatose
Does not respond, no response to external stimuli
in a CNS or upper motor neuron problem, patient will have:
increased or spastic muscle tone
positive Babinski
hyperactive reflexes
Motor Neuron problem (spinal cord lesion, polio), patient will have:
loss of muscle tone
negative Bobinski with hyporelfexia
Which of the following statements regarding reinforcement when assessing reflexes is true?
A. Used when reflexes are symmetrically hyperactive
B. Technique involves isometric contraction of other muscles
C. Supports the unsteady patient
D. All of the above
B.
Euthymic mental status:
normal
Dysthymic mental status:
depressed
Manic mental status:
elated
Hesitancies in speech are seen in patients with
aphasia from strokes
Monotone inflections are seen in patients with
schizophrenia or severe depression
Circumlocutions
words or phrases are substituted for the word a person cannot remember; e.g., “the thing you block out your writing with” for an eraser
Paraphasias
words are malformed (“I write with a den”), wrong (“I write with a branch”), or invented (“I write with a dar”)
don’t EVER use ammonia when assessing CN I because it triggers
CN 5
CN II is only place in the body that you examine
an actual nerve
pupillary response
goes in one eye through CN II, comes back from the cerebral cortex through CN III to constrict the pupils
ptosis
p is silent, drooping of the lid on one eye, can be a problem with CN III can also be congenital
cranial nerve IV does
looking down/in, convergence of eyes
cranial nerve VI is
looking away laterally
if there is a lesion in CN 7 (peripheral nerves synapse) you’re going to lose
the upper AND lower enervation of the face
bells palsy
if you ask to patient to raise their eyebrows, the forehead is not going to wrinkle, the eyebrows won’t raise, and there will be paralysis of the lower part of the face — so the nasolabial fold will be flat, the mouth may turn down, and then when you ask them to close their eyes, they won’t be able to do that tightly (lids will not approximate)
if someone comes in and you see they have some paralysis on their face, as long as they can close eyes and wrinkle forehead it’s probably
a stroke
stroke occurs
above the synapse in the pons
signs of a stroke
when you ask them to raise eyebrows, forehead will wrinkle, they will be able to close eye and it will approximate, but they will still have paralysis of the lower part of the face — flat nasolabial fold, mouth may turn down
spastic muscle tone
increased resistance to passive lengthening - if you take the arm and go through passive lengthening, it becomes super tight then relaxes - it’s like opening a pocket knife
happens with CVA (damage to the cortiocospinal tract)
rigid muscle tone
constant state of resistance
Leadpipe rigidity:
results when an increase in muscle tone causes a sustained resistance to passive movement throughout the whole range of motion, with no fluctuations.
Cogwheel rigidity
is a combination of lead-pipe rigidity and tremor which presents as a jerky resistance to passive movement as muscles tense and relax.
fasciculation vs tic
F: rapid continuous twitching of resting muscle or part of muscle - twitching of eye when you’re tired
T: normal movements of muscle groups such as winking or grinning that occur involuntarily and seemingly inappropriately
Tetany
too little calcium or magnesium, or tetanus disease
Myoclonus
little seizures - spasmodic jerky contraction of groups of muscles.
gradation of deep tendon reflexes
1+ diminished but could be normal (hypothyroidism)
2+ is normal, 3+ is brisker than average and could mean there’s some kind of disease
4+ is hyper-reflexia and definitely means there’s a disease process, usually have clonus (a little oscillation)
testing for clonus
if you have 3+ or 4+
support the knee in a partially flexed position, then quickly dorsiflex the foot - if you do that and it starts oscillating, then it’s a positive clonus
CN I
olfactory, smell, is fully sensory
CN II
optic: vision, it is also fully sensory
CN III
oculomotor: mixed type of nerve - for motor work, it does extra ocular movements and raises eyelids but also has parasympathetic function (pupil constriction, shape of lens)
CN IV
trochlear: primarily motor - does down and inward movement of eyes
CN V
rigeminal: mixed — motor section is muscles of mastication, sensory is 3 areas of sensation of face and scalp (forehead, cheek, chin), also some sensation of cornea is related to trigeminal, as are the mucous membranes of mouth and nose
CN VI
abducens: motor nerve that does lateral movement of eye
CN VII
facial nerve: mixed function — motor does facial muscles, sensory which is taste (on the anterior 2/3 of the tongue)
CN VIII
acoustic: sensory — hearing and equilibrium
CN IX
glossopharyngeal: mixed, motor does the pharynx (phonation, swallowing), and then sensory is taste on the posterior 1/3 of the tongue as well as the gag reflex
CN X
vagus: mixed function, motor is pharynx and larynx talking and swallowing, sensory is general sensation from the carotid sinus and the viscera of our abdomen
CN XI
spinal: motor, it’s the movement of the trapezius and sternomastoid muscles
CN XII
hypoglossal: motor, movement of the tongue
squamous carcinoma
an uncontrolled growth of abnormal cells arising in the squamous cells, which compose most of the skin’s upper layers (the epidermis). SCCs often look like scaly red patches, open sores, elevated growths with a central depression, or warts; they may crust or bleed
palpebral conjunctiva
The part of the conjunctiva, a clear membrane, that coats the inside of the eyelids
PRELOAD
the volume of blood in the ventricle at the end of diastole
As you examine the patient, remember three important neuro questions
Is mental status intact?
Are right- and left-sided findings the same, or symmetric?
If findings are asymmetric or otherwise abnormal, do the causative lesions lie in the central nervous system or the peripheral nervous system? CNS = upper motor neurons, PNS = lower motor neurons
