6901 Neuro Part I Flashcards
1
Q
Which structure has more space to expand, the brain or sc?
A
sc
2
Q
How do unmyelinated versus myelinated nerves travel?
A
unmyelinated= AP; myelinated= saltatory
3
Q
What do dendrites and axons do?
A
dendrites carry impulses to cell body and axons carry nerve impulses away from cell body
4
Q
What part of neuron is unmyelinated/gray?
A
cell body and some axons
5
Q
This provides support for neurons and has nutritive and metabolic functions. Has feet that project from cell and sometimes terminate on blood vessels and not other neurons? May play role in BBB?
A
astrocytes
6
Q
Type of brain cell that has role in CSF production?
A
ependymal cell
7
Q
Type of brain cell which participates in phagocytosis with CNS?
A
microglia
8
Q
Type of brain cell which provides insulation, by forming the myelin sheath around the brain and sc?
A
oligodendrites
9
Q
This type of cell provides insulation as forms myelin sheath in peripheral nerves?
A
Schwann cell
10
Q
How do neurons communicate with each other?
A
by means of NTs across synpases
11
Q
Inhibitory and excitatory NT?
A
major inhibitory is GABA; major excitatory is glutamate
12
Q
How does a GABA NT work?
A
(hyperpolarizing); it opens neuronal membrane Cl channels and produces hyperpolarization
13
Q
How does a glutamate NT work?
A
activation depolarizes neurons which makes it more likely that they will fire APs
14
Q
Where is GABA concentrated?
A
cerebral cortex, cerebellum, basal ganglia, spinal cord
15
Q
This NT is important in antagonizing the excitatory effects of amino acid NTs?
A
GABA
16
Q
This NT plays a large role in learning and memory and perhaps interactive and memory formation in awareness under anesthesia and the appreciation of pain?
A
glutamate
17
Q
Where is glutamate concentrated?
A
cerebral cortex, hippocampus, substantial gelatinosa of the sc
18
Q
This NT is released in excitatoxic neuronal injury after TBI or ischemic injury?
A
glutatmate
19
Q
How is glutamate formed?
A
deamination of glutamine supplied by Kreb’s cycle
20
Q
What are 3 categories of NTs?
A
monoamines (epi, dopa), amino acids (GABA, glutamate), neuropeptides (substance P, pituitary and endocrine hormones)
21
Q
How does glutamate work?
A
activates NMDA (ligand gated inotropic receptor) that cause conformational change in receptor and opens Na channel which results in depol of post synpatic membrane
22
Q
Neurons are classified according to and what are 3?
A
specific function; sensory, motor, interneuron
23
Q
Afferent part of neuron goes in what direction and is what type of neuron?
A
goes towards posterior root, is sensory
24
Q
Efferent part of neuron goes in what direction and is what type of neuron?
A
away from anterior root and is motor
25
What do interneurons do?
connect adjacent neurons
26
How much intracellular transport takes place in CNS and why?
very little bc lack transport mechanisms
27
What type of cells form tight junctions between adjacent cells to prevent transport of polar substances from intravascular to extravascular cerebral dept?
endothelial
28
What separates the 2 cerebral hemispheres?
longitudinal fissure
29
Describe the gyri?
is elevated and outer 3 mm area which is convoluted and increases the surface area
30
What do the sulci do?
grooves which separate the gyri
31
4 lobes of the brain?
frontal, parietal, temporal, occipital
32
Lobe of brain which is responsible for motor and thought?
frontal
33
Lobe of brain which is responsible for sense of pain, pressure, temp, and touch?
parietal
34
Lobe of brain which is responsible for hearing and smelling, recognition, and memory?
temporal
35
Lobe of brain whose function is vision?
occipital
36
Brainstem consists of?
midbrain, pons, and medulla
37
Part of brainstem that maintains consciousness, arousal, and alertness?
RAS
38
What does pons connect?
midbrain and medulla oblongata
39
This part of brain contains the respiratory and CV centers?
medulla
40
How many meningeal layers and spaces are there that cover the brain and spinal cord?
3 and 3
41
Meningeal layers going from outside to inside?
dura, arachnoid, pia
42
Meningeal spaces going from outside to inside?
epidural, subdural, subarachnoid
43
This meningeal layer is thin and avascular and serves as a major pharmacologic barrier?
arachnoid
44
This meningeal layer is thin, soft, highly vascular, and provides nourishment to spinal cord and brain
pia mater
45
This meningeal layer is thick and provides structural support to spinal cord?
dura mater
46
This meningeal layer forms a good portion of the BBB?
arachnoid
47
What is the space called above the dura mater?
epidural space
48
What is the space called between the arachnoid and pia?
subarachnoid space
49
What is the space called between the dura and arachnoid?
subdural
50
Which space contains the CSF?
subarachnoid
51
Pneumonic for memorizing CN names?
On Old Olympus Towering Top A Fin A(V)nd German Viewed S(A)ome Hops
52
Sensory/motor/both CN pneumonic?
Some Say Money Matters, But My Brother Says Big Brains Matter More
53
Angostroms between tight junctions in BBB and then in rest of body?
8; 65
54
Movement across BBB is governed by what 4 things?
size, charge, solubility, degree of protein binding
55
4 substances that struggle to pass thru BBB?
large molecules, high electrical charge, low fat soluble, polar molecules
56
Water, lipid soluble molecules such as (3) can pass thru BBB?
O2, CO2, anesthetics
57
Some problems which can cause a disruption in BBB?
HTN, TBI, subarachnoid or cerebral hemorrhage, ishcemia, mass or lesions
58
2 main arteries which supply blood to brain? Which supplies the anterior portion and which supplies the posterior portion?
internal carotid arteries and vertebral arteries; anterior: internal carotid; posterior: vertebral
59
Where does carotid bifurcate in to internal and external carotid arteries?
level of 3rd cervical vertebrae
60
CN whose motor control is of the face and salivation. Sensory is taste and cutaneous sensations
facial
61
CN which has motor control of some eye muscles and eyelid?
oculomotor
62
CN which has motor control of some eye muscles?
trochlear or abducent
63
CN which is responsible for chewing muscles and facial sensation?
trigeminal
64
CN which is responsible for motor impulses to pharynx and shoulder?
accessory
65
CN which is responsible for salivation, sensation of skin, taste, and viscera?
glossopharyngeal
66
CN which has motor control of tongue, some skeletal muscles, some viscera, and sensation from skin and viscera?
hypoglossal
67
8 ways in which CBF can be manipulated?
CMRO2, PaO2, PaCO2, autoregulation, temp, viscosity, ANS, anesthetics/meds
68
Normal rate of CBF?
50mL/100g/min of brain tissue
69
What percentage of CO is CBF?
15-20
70
As CBF changes so does?
CBV
71
Why does brain get disproportionately high part of CO?
high metabolic rate and inability to store energy
72
CMR is directly r/t?
of neurons and rate of depol
73
Gray matter gets what % of CBF and why?
80%, higher metabolic rate
74
How many mL/min is CBF?
700-750 mL/min
75
Too little CBF leads to? And too much CBF leads to?
ischemia; edema, bleeding
76
CPP=?
MAP- ICP or CVP (whichever is higher)
77
Where do you measure CVP?
at ear canal/meatus
78
Normal ICP?
79
Pressure that drives blood flow to the brain?
CPP
80
CPP is primarily dependent on? What's the exception?
MAP; increased ICP
81
When ICP> 30, what is compromised even with a normal MAP?
CBF CPP
82
A CPP of what can show flat EEG and result in irreversible brain damage?
25-40
83
Brain uses what % of total body O2 consumption?
20
84
CBF is tightly coupled to?
metabolism
85
High O2 consumption of brain is roughly what mL/min in adult?
50 mL/min
86
Neuronal activity in brain accounts for what % of energy use?
60
87
Most cerebral O2 consumption is used to?
generate ATP to support neuronal electrical activity
88
Increased ATP/energy leads to increased CMRO2 and therefore?
increased blood flow
89
What determines blood flow in the brain?
regional metabolism rate of O2
90
Primary fuel for brain is what and at what rate?
glucose; 5 mg/100g/min
91
How is ATP generated? And >90% of that is what type of process?
glycolysis; aerobic
92
CMRO2 parallels?
glucose consumption
93
Since the brain has no O2 stores, ATP stores are depleted and cellular injury can occur how soon?
3-8 minutes
94
What does mild hyperthermia do to the CMR and CBF?
increases and increases
95
CBF is directly influenced by ____= glucose consumption?
CMRO2
96
What is autoregulation?
ability of cerebral vasculature to maintain relatively constant blood flow despite large changes in BP
97
CBF maintains constant with CPP (MAP) between?
50-150
98
MAP for lower limit of autoregulation is?
>70
99
MAP> what disrupts the BBB and leads to edema and bleeding?
150-160
100
What does cerebral autoregulation curve do with chronic HTN?
shifts to the right
101
MAP
50
102
What does PaCO2 do to CBF and vasculature?
dilation and increases blood flow
103
Beyond autoregulation limits CBF is dependent on?
perfusion pressure
104
What can alter brain autoregulation?
brain injury or intracranial surgery
105
PaO2 has little effect on CBF until it falls below?
50
106
Most important regulator of CBF?
PaCO2
107
Hypocapnia does what to the vasculature?
constricts
108
CBF increases or decreases what % for each 1 mm change in PaCO2?
3
109
Do blood vessels in ischemic areas react the normally to changes in CO2?
no
110
One way to get a steal phenomenon w PaCO2?
hypoventilation with hypercarbia (increased CBF to normal areas)
111
One easy way to relax the brain to change the ICP?
hyperventilation
112
How long can hyperventilation relax the brain? And how quickly?
acutely (
113
PaCO2
30
114
What happens to CBF when PaO2
increases
115
ICP > 30 does what to CBF?
decreases
116
CPP
decreases
117
CPP > 150 does what to CBF?
increases
118
A decreased temp does what to neuronal metabolism and CBF?
decrease, decrease
119
CBF decreases what percent for every 1 degree Celsius decrease in temp?
5-7%
120
Hyperthermia does what to CBF and CMR?
increases, increases
121
Hypothermia is used for what and what do you have to monitor for?
high risk intraop ischemia; dysrthymias and coagulation dysfunction
122
Most important factor in viscosity?
hct
123
What does increased viscosity (increased hct) do to CBF?
decrease
124
What does decreased viscosity (decreased hct) do to CBF?
increase
125
Suggested optimal hct adequate for O2 delivery is?
30%
126
Intracranial vessels are innervated by?
SNS, PNS
127
What type of innervation may lead to passing out?
SNS
128
What does SNS innervation do to the vasculature and CBF?
constriction; decrease in CBF
129
What does PNS innervation do to the vasculature and CBF?
dilate; increases CBF
130
3 places where CSF is located?
subarachnoid space, cerebral ventricles, cisterns
131
Function of CSF?
bathes and cushions brain and spinal cord
132
Where is CSF produced and secreted?
produced by choroid plexus in the ventricles; secreted by ependymal cells of choroid plexus
133
CSF is produced at a rate of what? And the total volume at one time is? And how much is produced daily?
30 mL/h; 150 mL; 450-500 mL
134
How often does CSF volume replace itself?
3-4 hours
135
Normal CSF pressure is between?
5-15
136
% of brain, blood, and CSF in cranial vault?
80% brain, 12% blood, 8% CSF
137
Brain matter is composed of?
neurons, glia, interstitial fluid
138
Blood/fluid part of brain consists of?
blood, vascular space, ICF, ECF
139
Where is CSF reabsorbed?
arachnoid villi
140
Where does brain stem turn in to spinal cord and exit CNS in to spinal cord?
foramen magnum
141
Cerebral bolt or ventriculostomy in supine position pressure should be?
10-15 torr
142
ICP refers to?
supratentorial CSF pressure
143
An ICP of what is considered intracranial HTN?
15
144
Normal ICP?
5-15
145
4 compensatory mechanisms used when ICP is increased?
decrease CSF production, increase CSF absorption, displacement of CSF from cranial to spinal compartment, decrease in CBF (venous)
146
As the cranial volume increases, CSF is translocated in to?
spinal canal
147
Ischemia leads to?
cerebral edema and further increases in ICP
148
Symptoms of increased intracranial HTN?
HA (that wakes them up at night), N/V, blurred vision, somnolence and neuro deficits, papilledema, seizures/coma, Cushing reflex
149
3 s/s Cushing's triad?
HTN, bradycardia, respiratory irregularities
150
Some causes of intracranial primary HTN?
brain tumor, trauma, nontraumatic intracerebral hemorrhage, ischemic stroke, hydrocephalus, idiopathic or benign intracranial HTN, abscess, infection, cyst
151
Causes of extracranial/secondary HTN?
hypercarbia >35, hypoxia
152
Post op causes of intracranial HTN?
mass lesion (hematoma), edema, disturbances in CSF, increased CBV
153
What does edema look like on a CT scan?
region of hypodensity
154
What does increased airway or intrathoracic pressure do to venous pressure?
increased jugular venous pressure
155
6 things which increase CBV?
increased PaCO2, decreased PaO2, increased JV pressure, some anesthetics, vasodilators, seizures
156
Intracranial vault concentration is lost when ICP >?
30
157
Brain response to ischemia is?
edema
158
Increase in ICP and ischemia cause what reflex?
Cushing's
159
Normally cerebral ischemia leads to Cushing's reflex which will increase?
MAP
160
Cushing's reflex only compensates to a certain point and then what falls leading to further ischemia?
CPP
161
Why does a reduction in SBP aggravate ischemia?
causes reduction in CPP
162
2 compensatory mechanisms for high ICP?
translocation of CSF to spinal CSF space and venous blood to the extracranial veins
163
2 meds that increase ICF or ECF?
diuretics or steroids
164
Increases in blood volume are usually associated with increases in CBF. Exception is?
ischemia from hypotension or vessel occlusion at which time CBV may increase as cerebral vasculature dilates in response to reduction in CBF
165
3 things we can manipulate in CNS?
CSF: drain; blood volume: diuretics, steroids, positioning; cells (surgical removal glia, tumors, extravasated blood)
166
Gold standard for ICP monitoring?
intraventricular catheter
167
4 types of drains?
subdural bolt, ventriculostomy, epidural transducer, subdural fiberoptic catheter placement
168
Level drain w?
right atrium or angle of monroe
169
How do steroids help with CSF/fluid volume reduction?
decrease edema
170
4 diuretics to give to decrease CSF/fluid?
Lasix, hypertonic saline, Mannitol, Diamox
171
One way to decrease CBF?
decrease CBV
172
Decreased CBV and CBF does what to ICP?
decreases
173
Anesthesia can provide rapid alteration in which area of the intracranial vault?
CBV reduction/CBF reduction
174
3 things which increase CMR?
arousal, pain, seizures
175
Arterial blood volume can be reduced by?
preventing increase in CMR, barbs, optimizing hemodynamics
176
In hypothermia CBF (CMRO2) is decreased what % for every 1 degree C decrease in body temp below 37?
7%
177
Keep hct in what range to maximize O2 transport?
30-35%
178
Below what temperature can you not improve intracranial HTN?
35
179
Some ways to increase venous outflow and drainage?
elevate head, avoid constriction of the neck, avoid PEEP and excess airway pressures
