Nervous system Exam #1 Flashcards
1
Q
What are the 5 functions of the nervous system?
A
- Maintain homeostasis
- Generation of sensory input
- Process incoming data
- Generate impulses that control various voluntary and involuntary motor functions
- Storage of information
2
Q
What are the 2 types of cells in the nervous system?
A
neurons and neuroglia
3
Q
What are neurons?
A
the functional unit of the NS: transmits messages
4
Q
What are the 3 common characteristics of neurons?
A
!. excitablitity
- conductivity
- influence
5
Q
What is excitability?
A
ability to generate an impulse
6
Q
What is conductivity?
A
ability to transmit an impulse within itself
7
Q
What is infulence?
A
ability to influence another neuron
8
Q
What are the 3 main components of a neuron?
A
- cell body
- dendrites
- axon
9
Q
What is the cell body?
A
center, main part of neuron, forms gray matter*
10
Q
What are dendrites?
A
project from the cell body, receive nerve impulses and carry TOWARD cell body
11
Q
What are axons?
A
Project impulses away from cell body
12
Q
What is a myelin sheath?
A
lipid covering that insulates & speeds axon transmission. provides WHITE color to WHITE matter
13
Q
What are the 2 ways neurons are classified?
A
by function & by structure
14
Q
What are the diff functional classifications of neurons?
A
sensory (afferent), motor (efferent) or interneuron
15
Q
what are the diff structural classifications of neurons?
A
multipolar, bipolar, unipolar
16
Q
What are interneurons?
A
neurons that conduct impulses from one neuron to another (sensory to motor)
17
Q
What is the function of neuroglia or glial cells?
A
repair, support & protect neurons
18
Q
Which kind of NS cells are most common source of primary tumors?
A
neuroglia b/c they’re mitotic
19
Q
What are 4 types of glial cells?
A
- oligodendrocytes
- astrocytes
- ependymal
- microglia
20
Q
What is function of oligodendrocytes?
A
produce myelin sheath
21
Q
What is the function of astrocytes?
A
accumulate where neurons have been damaged, scar formation, feed neurons, form BBB
22
Q
what is the function of ependymal cells?
A
aid in secretion & regulation of CSF
23
Q
What is the function of microglia?
A
remove waste
24
Q
Which cell is called the “star of the nervous system”?
A
astrocytes
25
nerve regeneration: CNS? PNS?
CNS: limited ability to regenerate
PNS: very slow process
26
How are nerve impulses transmitted along axon? between neurons?
along axon = electrical transmission
| between neurons = chemical transmission
27
Electrical impulses are a result of which 2 ions moving into and out of cells?
potassium and sodium
28
What is the junction between nerve cells called?
synapse
29
What is the resting state of action potential?
no impulse, high K+ in cell, low Na+
30
What is depolarization?
channels in cell membrane open and Na+ rushes in
31
what is repolarization?
Na+ leaves cell, K+ reenters, after action potential ends
32
What is saltatory conduction?
nerve conduction of myelinated nerves, faster, impulse jumps from one node of ranvier to the next
33
What are 4 components of synaptic transmission?
presynaptic knob, synaptic cleft, neurotransmitter & receptor site
34
Which structures make up the CNS?
brain & spinal cord
35
What are the 3 subdivisions of the brain?
1. cerebrum
2. cerebellum
3. brain stem- midbrain, pons, medulla
36
PNS consists of:
12 pairs cranial nerves, 31 pairs of spinal nerves and autonomic nervous system
37
ANS is subdivided into?
sympathetic and parasympathetic nervous systems
38
What is the foramen magnum?
large hole in skull where brain stem & spinal cord connect
39
What are meninges?
3 protective membranes that surround the brain and SC
40
What are the 3 layers of meninges? describe each
1. Dura mater = outer layer, thick & tough
2. arachnoid = middle layer, thin, delicate = loosely contains brain and CSF
3. Pia mater = innermost layer, thin, mesh like, very vascular
41
What are the 3 meninge spaces?
1. epidural = above dura mater (between skull and dura mater)
2. subdural = below the dura mater (between dura & arachnoid)
3. subarachnoid = between arachnoid & dura mater (holds CSF)
42
What is the falx cerebri?
dural fold that separates 2 cerebral hemispheres (allows for some expansion)
43
What is the tentorium cerebelli?
double dura layer fold between cerebrum & the cerebellum
44
What are choroids plexus?
cauliflower-like, located in ventricles, produce & secrete CSF
45
What is a unique feature of the venous system of brain?
no valves, require gravity for drainage
46
Which arteries supply the anterior portion of brain?
common carotids
47
Which artery supplies the posterior portion of brain?
basilar artery
48
What is the circle of willis?
allows blood to circulate from 1 hemisphere to the other, safety valve to protect from occlusion & differential pressure
49
What forms the COW?
basilar artery & internal carotids
50
What are gyrus?
convolutions (folds) that increase surface area
51
Describe the cerebrum: function & anatomy
function: contains nerve centers associated with sensory, motor, and higher mental functions
anatomy: largest part of brain, divided into 2 hemispheres, each with 4 lobes
52
What are the 4 pairs of lobes called?
frontal, parietal, temporal & occipital
53
describe the frontal lobes:
contra-lateral, controls gross motor function, memory, higher cognitive function (problem solving), judgement & contains Broca's area
54
What is Broca's area?
controls expressive speech, located in the frontal lobe
55
What does damage to the frontal lobe cause?
difficulty forming words- called expressive aphasia
56
describe the parietal lobes:
primary sensory area, interprets sensory thought, controls body & spatial awareness
57
describe temporal lobes:
controls auditory reception, contains wernicke's area
58
What is Wernicke's area?
reception of speech, understanding written and spoken language, located in temporal lobe
59
what does damage to temporal lobes cause?
receptive aphasia
60
Describe the occipital lobes:
visual center
61
What are basal ganglia?
clumps of neurons in the base of brain responsible for initiation, execution & completion of voluntary movement
62
What makes up the diencephalons?
the thalmus, hypothalmus & limbic system
63
What does the medulla oblongata control?
body rhythms - respirations, BP, HR
64
What does the cerebellum control?
fine motor movements, balance & stability
65
What are the steps involved in a monosynaptic reflex?
receptor organ detects stimulus
sensory neuron is activated
information is processed in the spinal cord
motor neuron is activated , reflex occurs
NO BRAIN INVOLVEMENT
66
Which tracts carry sensory input to the brain?
ascending tracts
67
What does the dorsal column carry?
impulses of position sense, deep touch, vibration, pressure, kinesthesia
68
What does the spinocerebellar tract control?
muscle tension and body position
69
What do the spinothalmic tracts control?
pain & temperature
70
What do upper and lower motor neurons carry?
efferent messages that affects skeletal muscle
71
Where are UMN located?
in cerebral cortex
72
what do LMN connect?
connect CNS to muscle
73
What is the 1st & most important assessment during an evaluation of mental status
Level of consciousness
74
How do you test cerebellar function?
```
voluntary motor movement/ balance:
touch finger to nose
finger to examiner finger
rapid alternating movements
walk heel to toe
romberg's test
run heel down shit bilat
```
75
What is a Romberg's test?
stand feet together, arms by side, eyes closed. if swaying observed = positive romberg's
76
What do u test if superficial pain response is diminished?
temperature sensitivity
77
Which lobe is responsible for 2 point discrimination?
parietal
78
What is sterognosis?
ability to identify familiar objects using touch only
79
What is astereognosis?
inability to identify familiar objects using touch only
80
what is graphesthesia?
ability to identify letter or numbers when traced on palm of hand (eyes closed)
81
When testing reflexes, which number is normal?
2 (lower = diminished, higher = exaggerated)
82
What is clonus?
rhythmic oscillation that continues after a reflex has been activated
83
What is a neuro check?
shortened version of a full neuro exam, used for quick assessment & to identify changes and detect trends
84
What is the most sensitive indicator of neuro changes?
LOC
85
What criteria does glascow coma scale use to score?
eye opening, best motor & best verbal response. (lower number = worse)
86
What is decortication?
abnormal flexion response, spontaneously or with stimulus, sensory/motor cortex dysfunction (above the brain stem)
87
what is decerebration?
abnormal extension response (brain stem dysfunction)
88
NIH stroke scale: do you want high or low # ?
low # = better
89
What is cerebral angiography?
x-ray examination of cerebral vasculature using contrast medium, must be NPO prior
90
What are head CTs used for?
uses radiation to visualize changes in tissue density & abnormalities in size, shape & location of structures. Can detect edema, infarction, growths, clots, bleeding & skull fx
91
What is the Dx test of choice for neuro disorders?
MRI
92
What is MRA?
magnetic resonance angiography, shows vasculature of brain
93
What is a myelogram?
visualization of spinal column & subarachnoid space using a contrast agent
94
what is CSF analysis?
cerebrospinal fluid analysis, obtained via lumbar puncture, below L3
95
what is Electroencephalography?
Electrodes places on scalp with paste, electrical activity is recorded
96
What does EEG diagnose?
seizures, brain death, sleep disorders
97
What is EMG?
electromyography, needle electrodes are inserted into the muscle to evaluate nerve conduction, PAINFUL
98
What are evoked potentials?
evaluates impulse transmission & brain function by stimulating an impulse
99
What are 3 types of evoked potentials?
visual, auditory, somatosensory
100
What is PET?
positron emission tomography, provides 3D image to evaluate brain function
101
What is doppler imaging?
U/S and pulsed doppler combined to evaluate blood flow velocity in the carotid arteries.
102
What is transcranial doppler?
image flow velocity of intracranial blood vessels through thin areas of skull on temporal & occipital bones
103
What makes up the external ear?
the auricle (pinna) and the external auditory canal
104
What is cerumen?
ear wax
105
What is the ear drum?
the tympanic membrane
106
What is the function of the eustachian tube?
equalize pressure
107
What are the 3 ossicles?
3 bones of middle ear: incus, malleus & stapies
108
What is the equilibrium organ?
semicircular canals
109
What is the receptor organ for sounds?
cochlea
110
explain air conduction:
sound waves are transmitted through the air & picked up by the outer ear, waves cause the tympanic membrane to vibrate, which moves the ossicles, oval window pushes in and out and inner ear fluid makes waves, tiny hair cells move which stimulates a nerve impulse
111
How is sound measured?
```
dB= volume
Htz= pitch
```
112
explain bone conduction:
sound transmitted directly from skull to the fluids in the inner ear, bypasses external & middle ear
113
What is nystagmus?
blurry vision
114
what is vertigo?
sensation of moving or spinning
115
What is presbycusis?
hearing loss associated with aging R/T ear structure changes
116
What is a Rinne test?
vibrating fork placed first on pt mastoid bone, when pt indicates they can no longer hear it, it is moved a few inches from pinna. AC should be > BC
117
What is a positive rinne test?
| negative?
```
positive = AC > BC means sensorineural hearing loss
negative = BC > AC means conductive hearing loss
```
118
What is a Weber test?
stem of activated tuning fork is place on center of skull
119
How do you interpret a weber test?
normal= heard equally in both ears
conductive hearing loss= lateralizes to poor ear
senosorineural hearing loss= lateralizes to good ear
120
What is the most important tool for Dxing hearing loss?
audiometry
