Nervous System Flashcards
(292 cards)
1
Q
what are the 2 main parts of the nervous system?
A
central nervous system and peripheral nervous system
2
Q
what is in the central nervous system?
A
brain and spinal cord
3
Q
what is in the peripheral nervous system?
A
cranial nerves, spinal nerves, spinal nerves, autonomic nervous system
4
Q
What does the peripheral nervous system consist of?
A
all nervous structures outside of the brain and spinal cord
5
Q
What is the basic unit of the nervous system?
A
cell
6
Q
what does the neuron consist of?
A
cell body, dendrite, axon
7
Q
what is a dendrite?
A
carrying messages to the cell body
8
Q
what is an axon?
A
carrying messages away from the cell body
9
Q
what is a synapse?
A
a gap between two neurons
10
Q
messages travel across the gap by way of what chemicals?
A
neurotransmitters
11
Q
synapses may occur between what?
A
an axon and a cell body
12
Q
axon and dendrite fibers are always what?
A
protected
13
Q
axon and dendrite fibers are always protected with what exceptions?
A
some naked sensory nerve endings in the cornea of the eye
14
Q
Protection consists of what?
A
schwann cell
15
Q
where is the schwann cell located?
A
jelly roll configuration around axon or dendrite of indentation of nerve fiber into schwann cell
16
Q
schwann cell is high in what?
A
fat
17
Q
when the nerve fiber indents into the schwann cell the fiber is what?
A
non-myelinated
18
Q
when the schwann cell wraps around the nerve fiber like a jelly roll the fiber is what?
A
myelinated
19
Q
what is an advantage of myelination?
A
increased speed of nerve impulse transmission
20
Q
what is myelination caused by?
A
the insulating effect of many layers of schwann cell wrappings
21
Q
diseases that are demyelinating as MS cause problems with what?
A
nerve cell transmission
22
Q
when nerve cell fibers are damaged, the myelination may not heal and transmissions will do what?
A
be slower along the healed nerve fiber
23
Q
what are groups of nerve cell bodies within the brain or spinal cord called?
A
nuclei
24
Q
what color are nuclei
A
gray in color
25
what are groups of nerve cell bodies outside the brain or spinal cord called?
ganglia
26
what are bundles of nerve processes within the CNS called?
tracts
27
what color are tracts?
white
28
what are bundles of nerve processes in the PNS called?
nerves
29
what color are nerves?
white
30
what occupies the outer areas of a brain that is transected?
gray matter (nerve cell bodies)
31
what occupies the inner areas of a brain that is transected?
white matter (nerve cell processes traveling to other locations)
32
gray matter is located where?
centrally located
33
where is white matter located?
on the outer areas of the cord
34
where are nerve cell bodies located in the brain?
right under skull in outer areas of the brain
35
where are nerve cell bodies located in the spinal cord?
in the middle
36
What are the parts of the brain?
cerebrum, cerebellum, medulla oblongata
37
what are the different parts of the cerebrum?
right hemisphere, left hemisphere, longitudinal fissure
38
what are some important parts of the cerebrum?
cerebral cortex, olfactory bulb, thalamus, hypothalamus, corpus callosum
39
where is the cerebral cortex located?
outer layers of brain, surface area increased by foldings
40
what is the function of the cerebral cortex?
voluntary muscle control, reasoning, deep pain
41
where is the olfactory bulb located?
projects from anterior part of brain
42
what is the function of the olfactory bulb?
smell
43
where is the thalamus located?
round, circular area seen when cut brain in half
44
what is the function of the thalamus?
connects cerebral hemispheres wth brain stem and spinal cord
45
where is the hypothalamus located?
below thalamus on bottom surface of brain in front of brain stem
46
what is the function of the hypothalamus?
pituitary gland= hormonal control of the body, optic chiasm=optic nerve=sight, temperature regulation and water balance
47
where is the corpus callosum located?
white "c" shaped above thalamus
48
what is the function of the corpus callosum?
connects right and left hemispheres of the brain
49
what are the important parts of the cerebellum?
"tree of life"
50
where is the tree of life located?
interior resembles a tree or bush when cut longitudinally or transversely
51
what is the function of the cerebellum?
coordination
52
cranial continuation of the spinal cord, exits the skull at foramen magnum, cisterna magna is located in the angle between the cerebellum and the medulla oblongata, 4th ventricle are all parts of what?
medulla oblongata
53
what is the function of the medulla oblongata?
control of respiration, circulation, vomiting, swallowing
54
how many ventricles are located in the brain?
4
55
how many meninges are located in the brain?
3 layers
56
what are ventricles?
spaces in the brain which connect with each other
57
what do ventricles contain?
CSF
58
what are 1st and 2nd ventricles?
lateral ventricles
59
where is the right ventricle located?
in the right hemisphere
60
where is the left ventricle located?
in the left hemisphere
61
where is the 3rd ventricle located?
on midline distal to the R and L lateral ventricles
62
where is the 4th ventricle located?
between cerebellum and brain stem
63
what is the function of the ventricles?
to produce CSF
64
ventricles are lined with capillary network called what?
choroid plexus
65
CSF circulates from lateral to 3rd to 4th ventricles and out over the brain and spinal cord in what space?
subarachnoid
66
What are the functions of the CSF?
bathes brain and spinal cord and cushions brain and spinal cord
67
what does CSF provide to the brain and spinal cord?
nutrition
68
what can cells that fall off into CSF be used for?
sampled for diagnostic tests
69
CSF absorbs into veins of head and rejoins what?
circulation
70
If there is an obstruction to flow of lateral 3rd ventricle what can result?
tumor, blood clot, scar after injury, develops wrong
71
fluids build up why?
because it can't circulate
72
ventricle gets larger as what happens?
it fills with CSF
73
pressure on brain tissue does what?
compresses the brain
74
what is it called when the brain is compressed?
hydrocephalus
75
young skulls are not ossified so the cranium can expand reducing what?
pressure on the brain and less brain damage
76
in an older animal the skull cannot do what?
expand
77
in older animals cerebrum becomes thin due to what?
pressure
78
what is dura mater?
outside covering of brain
79
what is arachnoidea?
middle of brain
80
what is pia mater?
on the brain, spinal cord
81
what kind of layer is dura mater?
outer, tough, fibrous layer
82
dura mater blends with what?
periosteum on the inside of the skull
83
in the spinal cord the dura mater is separated from the periosteum but what?
fat-filled space
84
what is the fat filled space in the spinal cord?
epidural space
85
what is subarachnoid space?
location of spinal tap and spinal anesthesia
86
what is the function of pia mater?
inhibits movement of certain chemicals between CSF and brain tissue
87
what is pia mater also called?
blood brain barrier
88
what are the 2 nerves that enter and leave the spinal cord?
dorsal root and ventral root
89
dorsal root is what from the internal or external environment?
sensory from
90
ventral root is what to body?
motor to
91
after leaving spinal canal what branches to area of the body it serves?
spinal nerve
92
spinal nerves carry what fibers?
afferent and efferent
93
what is an afferent fiber?
dorsal root
94
what is an efferent fiber?
ventral root
95
What part of the body does each spinal nerve supply?
the area near where they exit from the spinal cord
96
where does the dorsal root brach to?
structures above transverse processes of vertebrae
97
where does the ventral root branch to?
structures below transverse process of vertebrae
98
what are nerves to limbs?
braid like arrangement of nerves from several spinal cord segments supplies the limb
99
forelimb
brachial plexus
100
hindlimb
lumbosacral plexus
101
how many cranial nerves leave the brain and emerge through carious foramina of the skull?
12
102
what do cranial nerves look like?
like spinal nerves but there is no ventral root
103
cranial nerves may be what?
strictly sensory, strictly motor, or mix of the 2
104
where do cranial nerves emerge from?
skull foramina
105
where do spinal nerves emerge from?
IV foramina
106
how are cranial nerves and spinal nerves the same?
like spinal nerves, cranial nerves carry ANS fibers
107
how else are cranial nerves and spinal nerves the same?
like spinal nerves, cranial nerves tend to supply a region near where they emerge from the skull
108
What is cranial nerve I for?
olfactory, smell
109
what is cranial nerve II for?
optic, sight
110
what is cranial nerve III for?
oculomotor, motor to the eye
111
what is cranial nerve IV for?
trochlear, moves eye
112
what is cranial nerve V for?
trigeminal, sensory to eye, face and motor to muscles that chew
113
what is cranial nerve VI for?
abducens, motor to eye
114
what is cranial nerve VII for?
facial, sensory/motor to head
115
spinal nerves are sensory to what?
the skin
116
spinal nerves are motor to what?
skeletal muscle
117
where is the phrenic nerve from?
branches of C5,6,7 to diaphragm
118
what does the phrenic nerve cause?
contraction
119
what is the supra scapular nerve?
muscles of the shoulder
120
what is the radial nerve?
muscles extend arm, forearm, place the front foot, sensory to dorsal surface of front foot
121
what is the obturator nerve?
adductor muscles hind leg
122
what is the sciatic nerve?
extensors of hip, adductors and rotator of thigh
123
what is the net effect for sympathetic?
fight or flight
124
what is the net effect for parasympathetic?
quiet, relaxed activity or rest and repose, vegetative
125
net effects are due to what?
sum of stimulatory and inhibitory nerve transmissions at end organ
126
ANS nerves travel with what?
cranial and spinal nerves
127
ANS nerves innervate what?
smooth muscle, cardiac muscle, and glands
128
What do ANS nerves do?
derive messages from these viscera and send information back to the CNS
129
where is the sympathetic nervous system derived from?
thoracic and lumbar segments of spinal cord
130
cell processes travels to ganglia near what with another neuron which travels to the organ or structure they supply
spinal column and synapse
131
where is the parasympathetic nervous symptom derived from?
cranial and sacral parts
132
nerve processes travel a long way to ganglion near what before they synapse?
the organ they supply
133
nerve impulses travel along nerve fibers in only one what?
direction
134
impulses don't lose what as they go along the nerve fiber?
strength
135
when do impulse transmits across synapse via chemicals called neurotransmitters?
at the end of the nerve fiber
136
neurotransmitter chemicals may either stimulate or do what?
inhibit the receptors sites on the next nerve or organ
137
with sufficient stimulation to reach what?
threshold
138
any one neuron will produce how many transmitter substance at all of its terminals?
only one
139
the one substance that a neuron will produce will be what?
either stimulant or inhibitor
140
what are some stimulants?
acetylcholine, norepinephrine, dopamine, and serotonin
141
all stimulants are what?
catecholamines
142
what are some inhibitors?
morphine and sedatives
143
stimulated to a fire impulse and do what further on?
impulse and transmit information
144
inhibited and no impulse is what?
fired
145
what is a threshold?
certain level of electrical charge that must be achieved before an action potential will be produced
146
the sum of stimulation+inhibition determines what?
the electrical charge of the membrane and whether threshold is reached
147
once threshold is reached what happens?
firing of the nerve impulse is always the same no matter how high the charge goes over the threshold level
148
if threshold is not reached what happens?
no firing occurs, no impulse is created
149
how do nerve fibers send their information to other cells and receive information from other cells?
divergence and convergence
150
what happens with divergence?
every nerve connects with many other nerve cells
151
when the nerve fires an impulse, the information does what?
spreads out to the other nerves with which it connects
152
what happens during convergence?
any on post-synaptic cell receives many axons from many different nerve cells
153
each axon brings what?
either stimulant or inhibitor information
154
the sum of the information coming in determines what?
what this post-synaptic cell will do
155
what is referred pain?
where pain from one area is "felt" in another area
156
nerves from visceral structures converge on and travels with what?
nerves from other places
157
the brain confuses the source of what?
pain
158
membrane changes at what membrane trigger release of neurotransmitter?
presynaptic cell
159
what is released at the synapse and crosses the gap between cells?
neurotransmitter
160
what changes at the post-synaptic cell membrane are triggered?
membrane
161
cells contain what?
electrolytes
162
extracellular fluid surround the cells contains what?
electrolytes
163
electrolytes have what?
a + or - charge
164
what electrolytes are we most interested in?
Na+, Ca+, K+, Cl-
165
What is the primary intracellular electrolyte?
K+
166
what is the primary extracellular?
Na+
167
depolarization occurs when there is increases permeability to what?
Na+
168
Na+ rushes into the cell and the charge in the cell becomes more what?
positive
169
when does repolarization occur?
after depolarization
170
increased cell permeability to what?
K+
171
K+ moves out of the cell and the cell charge returns to what?
the original level
172
Cell uses ATP to switch what to original positions?
Na+ and K+
173
Na+ moves outside to where?
extracellular area
174
K+ moves inside to where?
intracellular area
175
transmitter chemicals are produces where?
axon terminals and packaged vesicles
176
vesicles are released into synaptic gap in response to what?
an action potential traveling down the axon
177
electrolytes are involved in release of transmitter substances across what?
presynaptic cell membrane
178
If the neurotransmitter is a stimulant the postsynaptic receptor site membrane permeability to Na+ increases and allows Na+ to do what?
move into the cell
179
if enough Na+ moves in, electricity of the entire cell changes and the cell does what?
depolarizes
180
If the neurotransmitter is a stimulant, an action potential fires as Na+ rushes in all along the cell membrane this is a what?
a nerve impulse
181
the neurotransmitter is a what?
inhibitor
182
postsynaptic receptor site membrane permeability to K+ and Cl- does what?
increases
183
K+ inside the cell flows out and Cl- outside the cell does what?
flows in
184
the sum of stimulation and inhibition determines if cell will do what?
depolarize causing an action potential
185
what is the refractory period?
the resting time after the action potential is initiated
186
while the action potential propagates, nothing can cause another what?
action potential
187
while K+ is moving out a very strong stimulus can cause what?
action potential
188
the Na+ moving in must more than compensate for the K+ moving out to make the net sum more than what?
threshold
189
what is hypocalcemia?
low calcium
190
when does hypocalcemia happen?
post part when large demand for Ca+ in milk
191
animal is weak during hypocalcemia due to what?
lack of Ca+ to initiate nerve transmissions
192
during hypocalcemia, muscle contractions are what?
weakened or absent
193
what is hypokalemia?
occurs with use of certain diuretics
194
during hypokalemia, lack of K+ overall means less K+ inside the cell this makes the cell more what and less likely to reach threshold and depolarize?
negative
195
what is the result of hypokalemia?
weak animal
196
drugs, alkalosis,acidosis, anesthetics, hypoxia, immune disease affect what?
nerve transmission
197
what drugs act at the synapse?
morphine, strychnine, tranquilizers
198
what does morphine do at the synapse?
relaxed
199
what does strychnine do at the synapse?
tense, muscle stiffness, seizures
200
what do tranquilizers do at the synapse?
relaxed
201
in alkalosis, increased body pH causes what
increased neuron excitability
202
what is possible in alkalosis?
post-vomiting where lots of HCl is lost in the vomitus
203
in alkalosis, decreased Cl- means there is less Cl- outside the cell to move into the cell with the action of what
inhibitor neurotransmitters
204
in acidosis, decreased body pH causes what?
decreased neuron excitability
205
what is possible in acidosis?
post-diarrhea where K+ and Na+ are lost in the diarrhea
206
less K+ is located in the cell so the interior charge of the cell is more what?
negative
207
what do anesthetics do for the passage of nerve impulses?
inhibit or completely block
208
general anesthetics affect what?
CNS
209
sedatives and hypnotics decrease what?
nerve irritability and tend to induce sleep
210
during hypoxia, low oxygen supplies result in what?
decreased excitability of neurons
211
in immune disease, antibodies are against what?
neurotransmitters and receptor sites
212
what do reflex arcs consist of?
afferent neuron, efferent neuron, upper motor neurons
213
upper motor neurons may alter what?
a simple reflex
214
what is a simple reflex arc?
spinal reflex
215
in a spinal reflex, neurons at the level of the spinal cord are able to do what?
initiate the relfex
216
in spinal reflex, information from the body stimulates what?
a nerve cell
217
in spinal reflex, the information goes to what?
the spinal cord
218
in spinal reflex, what is not involved?
the brain
219
what is a lower motor neuron?
efferent nerves going to skeletal muscle structures
220
what is an upper motor neuron?
all nerves descending cranial to the LMN
221
what regulates and controls the activity of the LMN but does not initiate the LMN action?
the UMN
222
LMN lesion will cause what?
loss of function of the structure supplied
223
UMN lesion will cause what?
altered function of the structure supplied by the LMN
224
patellar reflex-tap ligament at stifle, flexor reflex-gently pull foot, extensor thrust-push foot against body and foot pushes back, visceral reflexes are all examples of what?
spinal reflexes
225
involve reflex centers in the brain, information will travel spinal cord to brain and then back to spinal cord, reflexes involving just the head do not use the spinal cord are examples of what?
complex reflexes
226
the medulla oblongata handles what 3 main areas?
circulation, respiration, and vomiting and swallowing
227
what does the medulla oblongata handle in circulation?
heart action and vessel size
228
what does the medulla oblongata handle in respiration?
respiration, coughing, and sneezing
229
tonic neck reflexes causes what?
increased tone of extensor muscles of the forelimb and decreased tone of extensor muscles of the hindlimb
230
what is tonic eye reflexes?
move the head and the eyes keep looking in the original direction
231
what is extensor postural thrust?
allows for support of the weight of the body without thought
232
what is righting reflex?
bend foot over, returns to normal position
233
radial nerve must do what?
work for this reflex to function properly
234
what is placing reflex?
touch side of foot to table, lifts and places foot
235
sensory input+muscle action is what?
needed
236
what CN is auditory reflex?
CN VIII
237
what CN are pharyngeal reflex?
CN IX, X, XI, XII
238
what is pupillary light reflex?
direct and indirect CNII in and VII out
239
What CN is palpebral reflex?
CN V in and VII out
240
what CN is menace?
CN II in and CN III, VI, IV out
241
what is menace?
object coming near to eye elicits a blink
242
what is deep pain?
different from withdrawal reflex because brain is involved
243
what CN are used in deep pain in the lip area?
CN V in and VII out
244
what is corneal reflex?
used in anesthetic monitoring of the horse--touch the cornea
245
what CN are used in corneal reflex?
CN V in and CN III out
246
what is the major role of the autonomic nervous system?
maintain homeokinesis
247
the pituitary gland receives stimuli and produces what?
hormones as a response
248
stimuli may reach the pituitary gland by what?
nerve pathways or by circulating hormones
249
how does the pituitary exert control over body functions and homeostasis?
by hormonal control
250
the hypothalamus exerts its control over the sympathetic and parasympathetic systems by doing what?
influencing the signals that pass to the PS and sympathetic nerve fiber portions of the spinal cord and brain stem
251
where do parasympathetic fibers come from?
the brain stem
252
where do sympathetic fibers come from?
thoracolumbar spinal cord areas
253
the effect of the sympathetic nervous system is opposite to the effect of what?
parasympathetic nervous system
254
what will the overall effects be of stimulation in the sympathetic system of HR?
increased
255
what will be the overall effects be of stimulation in the sympathetic system of BP?
increased due to vasoconstriction
256
what will be the overall effects be of stimulation in the sympathetic system of bronchi and pupils?
dilate
257
what will be the overall effects of stimulation in the sympathetic system of GI?
decreased activity
258
neurotransmitter released is norepinephrine similar to epinephrine produced by what?
adrenal glands
259
what are the 4 adrenergic receptors?
alpha 1, alpha 2, beta 1, beta 2
260
what does alpha 1 do in smooth muscle contraction?
arterioles constrict, increased tone of urethra, pupil dilates
261
what does alpha 2 do?
skeletal muscle constriction
262
increases HR, increased AV node conduction velocity, increased force of contraction of heart muscle, kidneys release renin are all jobs of what?
beta 1
263
smooth muscle relaxation, opens airways and blood vessels supplying skeletal muscles are all jobs of what?
beta 2
264
dilation of coronary blood vessels and blood vessels in kidneys, mesentery are all jobs of what?
dopaminergic
265
what happens to HR in parasympathetic system?
decreases
266
what happens to BP in parasympathetic system?
decreases
267
what happens to bronchi in parasympathetic system?
constricts
268
what happens to pupil in parasympathetic system?
constrict
269
what happens to GI in parasympathetic system?
increases
270
cholinergic receptors are termed what?
muscarinic and nicotinic
271
muscarinic does what?
slows HR, contracts urinary bladder, increases salivation, constricts pupil
272
nicotinic does what?
receptors on all skeletal muscle cells, adrenal medulla and in all autonomic ganglia
273
divergence of axons means multiple areas of the body are affected at any one time, some of the organs innervated secrete hormones directly into the blood stream and therefore have a rapid total body effect are all reasons we are able to see what?
ANS wide-spread effect
274
death of any nerve cell may be serious because nerve cells cannot do what?
be replaced
275
injury to nerve processes may or may not be what?
permanent
276
injury to nerve processes happens most with what?
peripheral nerves
277
peripheral nerve injuries tend to cause loss of what to a localized area?
sensation or muscle activity
278
central nervous system damage tends to have more what?
general effects
279
what does CNS cause?
partial or complete paralysis, spasms, convulsions
280
most fiber tracts from one side of the brain cross to opposite side of what?
the spinal cord
281
a lesion on one side of the brain will be manifested as impaired functioning of the opposite of what?
the body
282
crushing injuries cause what?
temporary paralysis of adductor muscles
283
crushing injuries recover how?
spontaneously
284
cutting a nerve by wire, a fractured bone, if the cell body and dendrite remain healthy what may occur?
regrowth of the axon
285
each fiber grows how long per day?
1-3 mm
286
once axons are rejoined, transmission of impulses will be slower because diameter of healed nerve fiber is less than diameter of original nerve fiber and myelination may be affected but what may be restored?
function
287
what are neuromas?
tangled masses of nerve fibers
288
when do neuromas result?
when new fibers growing out become entangled instead of growing to the effector organ
289
what do neuromas produce?
phantom sensations
290
what are phantom sensations?
sensations produced from nerve fiber endings that normally would be farther away
291
what do phantom sensations feel like?
as if the whole nerve exists
292
what is an example of phantom sensation?
"nerve" a horse, a neuroma develops and the pain returns
