A&P Exam 4 Flashcards
1
Q
What is the nervous system
A
the master controlling and communicating system of the body
2
Q
structural classification
A
based on where a component is located
3
Q
central nervous system
A
CNS composed of the brain and the spinal chord
acts as an integration and command center
4
Q
peripheral nervous system
A
PNS anything outside the CNS mostly nerves (sensory cells) cranial nerves (spinal nerves)
5
Q
What is the function of nerves
A
connect the body to the CNS
6
Q
functional classification
A
based on how a component is regulated
7
Q
somatic nervous system
A
targets the skeletal muscles
under conscious control
8
Q
autonamic nervous system
A
targets smooth muscle and cardiac muscle
under unconscious control
9
Q
neurons
A
a type of cell present in neural tissue
10
Q
nervous tissue
A
highly cellular
high rate of metabolism
needs lots of glucose and O2
poor capacity for repair
11
Q
what are neurons for
A
the functional unit of the nervous system
(smallest piece that still works
12
Q
what is the structure of neurons
A
large cells with long processes
do not divide (amitotic) (few exceptions)
13
Q
how many neurons does the body contain
A
10^12 neurons
14
Q
where are neurons located
A
mostly in brain
15
Q
what is the life of a neuron
A
long lived
16
Q
cell body of a neuron
A
also called the soma
17
Q
what does the cell body of a neuron do
A
portion that controls the bulk of the cytoplasm
18
Q
what does the cell body of a neuron contain
A
most organelles
19
Q
dendrites
A
short branching extensions of a neuron
20
Q
where do you find dendrites
A
off of cell body
21
Q
what are dendrites for
A
input end of the neuron
22
Q
axon
A
long and thin single extension
23
Q
how long is the axon in a neuron
A
up to 3 feet long
24
Q
how many axons in a neuron
A
only one
25
what is the axon in the neuron for
output end of the neuron
26
where is the axon located
arises from the cell body at the axon hillock
27
what is the plasma membrane of an axon called
axolemma
28
how many major projections do neurons produce
3 or more (an axon and a cluster of dendrites)
29
bipolar neurons
optic relay
30
unipolar neurons
sensory
31
axon terminals
hold and release neurotransmitters (granules)
32
where are the axon terminals found
at the distal tip of the axon
33
where are the axon terminals
at the synapse which is a connection between two neurons
34
myelin sheath
white fatty segmented layer that can be around an axon
35
what does the myelin sheath do
electrically omsulates the axon
36
what is myelin sheet composed of
schwann cells which wrap around axon about 200xs and do not touch neighbors
37
nodes of Ranvier
spaces between cells in myelin sheath shcwann cells
38
cell structures particular to a neuron
```
cell body
dendrites
axon
axon terminals
myelin sheath
```
39
nucleus
a cluster of neuron cell bodies in CNS
40
ganglion
a cluster of neuron cell bodies in PNS
41
TRACT
a bundle of neuron extensions in the CNS
| a bundle of axons or long dendrites
42
nerve
a bundle of neuron extensions in the PNS
43
white matter
portions of CNS that appear white to the naked eye composed mostly of myelinated axons
44
gray matter
portions of the CNS composed mostly of cell bodies or unmyelinated axons
45
where do neurons carry information
to or from the brain
46
afferent neurons
bring information to brain
47
efferent neurons
take information out of brain
48
interneurons
stay within the brain
49
neuroglia
cells in nervous tissue that support neurons
50
neuroglia characteristics
smaller than neurons but present in much greater number
51
astrocytes
found in the CNS most abundant
52
what do astrocytes to
very versatile
process extracellular fluid
connect neurons to capillary beds
support axonal growth and guidance
53
microglia
found in the CNS
| a type of fixed macrophage
54
microglia function
immune cells to engulf and destroy
55
ependymal cells
found in CNS
| line fluid filled cavities of brain and spinal chord
56
ependymal cells
cilia on these cels wave to circulate cerebral spinal fluid
57
olgodentrocytes
found in CNS
| forms the myelin sheath in the brain
58
satellite cells
in the PNS
surround neuron cell bodies in ganglia
similar in function to astrocytes
59
schwan cells
in the PNS
wrap tightly around axons in nerves
forms myelin sheaths in PNS
60
basic principles of electricity
same for both natural and artificial circuits
61
manmade circuits
we transfer charge using electrons
62
the human body circuits
transfer charge using ions (electrolytes)
63
voltage
V measure potential energy of separated charges (+ - )
64
what does voltage measure in
volts
65
voltage aka
cell potential or membrane potential
66
current
I measures the flow of electrical charge from one point to another
67
what do currents measure in
Amperes
68
charge
Q measures the total number of charged particles moved by a current
69
what does charge measure in
coulumbs
70
resistance
R the hindrance or opposition to the flow of ions
71
resistance formula
1/R = G = CONDUCTANCE
72
conductance measure
it's measures in suemens
73
what is conductance
how easy it is to flow charge through a channel
74
ohm's law
voltage is linked to current resistance
75
what does ion flow lead to
voltage changes
76
ohm's law process
no voltage change without a current
form a current by flowing ions
ions flow through open channels
77
ion channels in the plasma membrane
allow polar ions to cross the non polar membrane
78
how are channels named
by the substance that passes through them
or
channels are also named by how they open
79
examples of naming channels by their substance pass
Sodium channels or glucose channels
80
examples for channels named by how they open
upon the stimulus that opens them
81
channel types
ligand-gated
voltage-gated
mechanically-gated
leak
82
ligan-gated channels
binding of a chemical causes channel to open
83
different name for logan-gated channels
chemically gated
84
example of ligand-gated channels
acetylcholine receptor
85
voltage-gated channels
a large change in charge causes channel to open
86
example of voltage gated channels
calcium channel in t-tubule
87
mechanically-gated channels
a physical stimulus opens channel
88
example of mechanically-gated channels
channel in inner ear
89
leak channels
always open found on neurons
low conductance
leaks potassium
90
where is ligand dated channels found
axon dendrites
91
where are voltage-gated channels
axon hillock
92
ion movement
ions can cross the plasma membrane when a channel is open ONLY
93
what direction do ions from when a channel opens
either way in to cell or out of cell
94
how is the direction of flow predictable
using chemical gradient
95
electrical influence in predicting flow direction
charge interaction (+, -) opposites attract
96
chemical influence in predicting flow
concentration gradient - ions diffuse (move to lower concentration)
97
depolarization
event that moves voltage towards 0mV
98
hyperpolarization
event that moves voltage away from 0mV
99
repolarization
event that moves voltage back to its' original resting value to -70mV
100
a neuron at rest
a neuron that is not being actively stimulated
101
sodium-potassium ATP-ase pump
pump is always on
pump establishes an imbalance of ions
pump is electrogenic
102
what does NA/K ATP-ase pump do at rest
forces out 3 NA while bringing in 2 K at the loss of 1 ATP
103
cations
possitively charged
104
anions
negatively charges
105
A-
large ions organic molecules too bigg to fit through channel
- proteins
- organic acids
- vitamins
106
Na distribution at rest
inside the cell 15mM
| outside cell 140 mM
107
Potassium distribution at rest
140mM inside cell
| 5mM outside cell
108
Cl- distribution at rest
10mM inside cell
| 120 mM outside cell
109
A- distribution at rest
100mM inside cell
| 0.2 mM outside cell
110
resting cell potential
all gated channels are closed
leak channel is always open
pump is always on
resting voltage sits at -70mV
111
what will a stimulated neuron produce
an action potential
112
what is the interior of the cell like
negatively charged
113
what happens to unpaired ions
get left behind
114
resting neurons
sit at -70mV
| all gated channels are closed and not producing currents
115
what happens when voltage-gated Na channels open
Na flows in to cell
| causes voltage to move from -70mV all the way up to +30mV
116
What happens when voltage-gated K channels open
changes voltage from +30mV to -75 mV
117
K efflux
causes a short hyperextension period
| - leak channel and NA/K ATP-ase reestablishes resting conditions from -75mV to -70 mV
118
Action potential conduction
when an action potential is produced it moves along a neuron
119
where do new axon potentials form at
always at the axon hillock
120
how do action potentials move
down axon, away from cell body
121
where does action potential arrive
at axon terminals
122
signaling strength
action potential does not change - it is all the same size
123
what do we do since we cannot send bigger action potentials
we must send more of them more often at an increased frequency
124
conduction velocity
the speed an action potential travels down the axon
125
factors of conduction velocity
axon diameter
| degrees of myelination
126
axon diameter
bigger has faster conduction velocity
| smalles is slower conduction velocity
127
degree of myelination
more myelin conducts faster
less myelin is slower
it's possible to have no myelin
128
saltatory conduction
how an action potential moves down an axon with myelin present
129
what does myelin do to conduction
myelin increases the resistance of the membrane
| forces action potential in to neuron and it travels much faster
130
how does an action potential travel in myelin
it reappears at plasma membrane in the nodes of Ranvier
| action potential is allowed to jump ahead
131
multiple sclerosis
auto immune disease
132
what happens with multiple sclerosis
immune system kills schwan cells
| causes demylenation of axones
133
what happens to action potential in multiple sclerosis
slows and can even stop
134
what does MS cause
causes progressive muscle weakness eventually paralysis
135
neuron classification
based on conduction velocity
136
group A fibers
large diameter axons
large amount of myelin
fastest conduction neurons (over 300 mph)
137
group B fibers
small diameter axons
some myelin
slower conducting neurons (at 30 mph)
138
what system are group A fibers used by
somatic nervous system
139
what system does group B fibers use
ANS
140
group C fibers
smallest diameter axon
no myelin
slowest conducting neurons (2 mph)
141
what are group C fibers used by
AND in local reflex arcs
142
synapse
junction between two neurons or between a neuron and muscle cell
143
electrical synapses
modified gap junctions
common during development
can be in CNS as adults
144
what do electrical synapses use
channel to allow ions to flow between two cells
little control over signaling
bidirectional communication
145
chemical synapses
uses a neurotransmitter
146
how much control is there in chemical signaling
a lot
147
what type of communication in chemical synapses
unidirectional
| one particular neuron is always in charge
148
presynaptic cell
neuron before the synapse
cell has produced an action potential
axon terminals are at the synapse
149
postsynaptic cell
comes after the synapse
dendrites are at the synapse
cell is receiving neurotransmitter
150
signaling via chemical synapses for presynaptic cell
action potential arrives at axon terminals
Ca channels open
Ca enters Ca in neuron allow granules of neurotransmitter to fuse
neurotransmitter is released in to the synaptic cleft
151
signaling via chemical synapses in postsynaptic cell
neurotransmitter binds to its specific receptor on postsynaptic cell (acetylcholine)
the acetylcholine receptor is a ligan-gated channel
a small Na current moves in to the cell
the affect on postsynaptic cell ends when neurotransmitter goes away
152
how can a neurotransmitter go away
can be taken back into presynaptic cell
| can be destroyed
153
What is the name of the enzyme that destroys neurotransmitter
Acetylcholinesterase
154
What is it called when a neurotransmitter is taken back in
Reuptake
155
graded potentials
release of neurotransmitter into the synaptic cleft causes the postsynaptic cell body to produce a current
156
what is a small current called
a graded current
157
what will a small current (graded current) cause
small changes in voltage called postsynaptic potentials or migrated potentials
158
graded potentials fading
they fade rapidly with time and distance
159
how are graded potentials produced
using ligand-gated channels
| low conductance channels
160
where are graded potentials formed
in the dendrites and the cell body
161
graded potential strength
vary
| it is directly proportional to the amount of neurotransmitter in synaptic cleft
162
EPSP
excitatory postsynaptic potential
163
what are EPSP for
always depolarizes postsynaptic cell and changed voltage toward threshold
164
IPSP
inhibitory postsynaptic potential
165
what are IPSP for
always hyper polarizes the postsynaptic cell and moves cell voltage away from threshold
166
summation
a postsynaptic neuron feels a greater effect from a presynaptic cell when the stimulus us strong or if stimuli are frequent
167
temporal summation
add graded potentials that are near in time
168
what do presynaptic neurons produce during temporal summation
many graded potentials in a row
169
spatial summation
add graded potentials that are near in distance
170
what do multiple presynaptic neurons produce in spatial summation
graded potential at the same time
171
result of input
postsynaptic neuron must decide whether or not to form its own action potential
172
how does a postsynaptic neuron decide to form its own action potential
based on the sum of graded potentials
can have EPSP or IPSPS
can sum several small graded potentials or only one
173
when will a postsynaptic cell for its own action potential
if it depolarizes to -55mV at axon hillock
174
subthreshold potential
some EPSP are too weak to trigger a new action potential -65mV to -56mV
175
synapse localization
a synapse that is closer to the postsynaptic axon hillock has a greater effect
176
axodendritic synapse
connects to dendrites
177
axosomatic synapse
connects to cell body
178
axoaxonic synapse
connects to axon hillock
179
neurotransmitters
are signaling chemicals released from the axon terminals
180
how many neurotransmitters can a neuron release
one or several
181
receptors
each neurotransmitter has its own
182
what does a direct acting neurotransmitter do
opens a channel
183
what does an indirect neurotransmitter do
activates second messenger pathways
| no channels- intracellular signaling cascades - long lasting effects
184
acetylcholine
first neurotransmitter ever identified
185
what is acetylcholine used in
neuromuscular junction as part of the ANS
186
Norepinephrine
pleasure neurotransmitter in the CNS
| used as part of the ANS
187
what can enhance norepinephrine release
amphetamines
188
what does cocaine and some antidepressants cause for norepinephrine
removal from synaptic cleft is inhibited
189
dopamine
pleasure neurotransmitter in CNS
| linked to several disorders
190
what disease is dopamine deficient in
parkinsons disease
191
what disease is linked with increased activity of dopamine
schizophrenia
192
serotonin
regulates mood
| more of it makes you happy
193
what does prozac and ecstacy cause to serotonin
blocks the removal of it from the synaptic cleft
194
what is serotonin released by
food mostly sugary foods
195
what are Biogenic Amines
Norepinephrine
dopamine
serotonin
196
GABA
gaba-aminobutyric acid
197
what does GABA do
major inhibitory neurotransmitter of the brain
| opens CL channel - hyper polarizing - forms IPSPS
198
glutamate (MSG)
major excitatory neurotransmitter forms EPSPS
| several subtypes of channels
199
one subtype of glutamate channels
involved with learning and memory
200
neurotoxicity
brain can suffer damage due to excessive glutamate release
| return of O2 causes so much glutamate signaling that neurons die
201
type of amino acids
GABA
| Glutamate
202
endorphins
inhibit pain under stressful conditions
203
examples of endorphins release
long strenuous exercise and childbirth
204
tachykinins
involved with pain transmissions
205
where are tachykinins released from
damaged tissues
206
the brain
one of the primary structures of the CNS
207
what does the brain do
acts as a major control center of the body
208
what is the brain composed of
very soft tissue
209
how much does the brain weight
3-4 lbs in an average adult
210
how is the brain composed
4 major regions
211
4 regions of the brain
cerebral hemisphere, brain stem, cerebellum, diencephalen
212
ventricles
fluid filled cavities with the brain
| are continuous
213
what are the ventricles filled with
cerebral spinal fluid (CSF)
214
what are ventricles lined with
ependymal cells that help to circulate the CSF
215
lateral ventricle
longest C-shaped deep to cerebral hemisphere
216
third ventricles
deep to diencephalon
217
fourth ventricles
deep to brain stem
continuous with central canal of the spinal cord
single channel
218
cerebral hemispheres
form the superior and superficial portion of the brain
| longest part of the brain 80% of brain mass composed of 3 different areas
219
cerebral cortex
superficial area of grey matter
| absolute type of brain
220
cerebral white matter
composed of deep white matter myelinated axons
221
basal nuclei
deep islands of grey matter found within white matter
222
folding
the surface of the cerebral hemispheres is extensively folded
223
what is the purpose of folding in the brain
increases the surface area of the brain
| holds more neurons in brain making us more intelligent
224
a gyros (many gyri)
an elevated ridge of brain tissue
225
a sulcus (many sulci)
a shallow groove in brain tissue
226
a fissure
deeper groove in brain tissue
227
lobes
each cerebral hemisphere is divided by sulci into five distinct lobes
228
4 superficial lobes
frontal
parietal
temporal
occipital
229
1 deep lobe
insula
230
central sulcus
separates the frontal lobe from the parietal lobe
231
lateral sulcus
outlines the top of the temporal lobe
232
cerebral cortex
the outermost layer of the cerebral hemisphere
233
mapping
an approximation
234
functional areas of the cerebral cortex
a map of the cerebral cortex localizes regions with different functions
235
what does the cerebral cortex control
most somatic processes
| conscious portion of brain
236
3 major types of areas in the cerebral cortex
motor areas - sensory areas - association areas
237
sensory areas
vision, smell, taste, hearing, touch
238
cerebral cortex control
composed of two equivalent but not identical sides
| left and right hemispheres
239
left and right hemispheres
each side is concerned with the opposite side of the body
| called contra lateral control
240
ipsilated
same side
241
what is the left hemisphere for
more logical, better at math, controls language
242
what is the right hemisphere for
more artistic, visual side of brain, creative side, nonverbal language
243
motor areas
control voluntary (somatic) movements
244
primary motor cortex
used to stimulate skeletal muscles
| - initiating voluntary movements
245
where is the primary motor cortex found
in the posterior portion of the lobe
246
what do the primary motor cortex contain
very large neurons (pyramidal cells)
247
what happens when the primary motor cortex is damaged
will result in paralysis
248
what do neurons that are located together do
move a particular body part
important parts are given more neurons
(hand, face, tongue)
249
homunculus
a distorted odd looking figure in the mapping
250
epilepsy what is it due to
excess electrical activity in the brain
| usually from an overactive cluster of neurons
251
what does the excess electricity do during epilepsy
spill into areas of the brain
252
what happens when excess electricity spills in to brain
impair normal motor function
can affect motor and sensory functions
causes skeletal muscles to contract and false senses
253
severity of seizures
can vary
254
petit mal seizures
also called absence seizures
255
severity of petit mal seizures
less or lower in severity
256
characteristics of petit mal seizures
blank facial expressions and facial muscle twitches
257
who does petit map seizures affect
common in children up to 10 years of age
258
grand mal seizures
tonic clonic seizures
259
severity of grand mal seizures
more severe than other one
260
characteristics of grand mal seizures
false sensory information and convolutions
| uncontrolled muscle contractions as signals reach the primary motor cortex
261
what precedes grand mal seizures
an aura, a flash of light
262
premotor cortex location
in frontal lobe
| sits anterior to primary motorcortex
263
what does the premotor cortex control
learned motor skills that are pattered
| - cycling, walking, chewing, typing
264
where does the premotor cortex send patterns to
the primary cortex
265
what happens when the premotor cortex is damaged
loss in patterned skills
| can be relearned
266
Broca's area location
in the frontal lobe
267
what are the broca area's function
for muscles used for speech
| usually active when we plan to speak
268
where is the broca area found
only in left hemisphere of the brain
269
frontal eye field location
in the frontal lobe
270
what does the frontal eye field control
voluntary movement of the eyes
271
sensory areas
involved with conscious perception of stimuli
272
primary somatosensory cortex location
in the parietal lobe
| just posterior to the central sulcus
273
what does the primary somatosensory cortex do
spatial discrimination of somatosensory input
| Locates the part of the body that is being touched.
274
what uses the primary somatosensory cortex the most
areas of the body that are more sensitive to touch
hands feet face tongue lips genitals
uses more neurons
appear larger on map and form a homunculus
275
somato
means touch
276
somatosensory association cortex location
parietal lobe behind primary somatosensory cortex
277
what does somatosensory association cortex do
integrates information coming into the brain in an attempt to understand an object that is being felt
278
somatosensory association cortex continued
allows for ID based on touch
texture size and shape
ID using prior experience
279
primary visual cortex location
located at the posterior tip of the occipital lobe
280
primary visual cortex
largest of all cortical sensory areas
vision uses the most brain power - color - depth perception
processes info from eyes to produce vision
281
visual association area location
also in occipital lobe
282
Auditory association area
allows us to identify current sounds
compares current sounds to known sound and using memories
Also in temporal lobe
283
gustatory cortex
association area identifies taste perceives taste, located in insula
284
olfactory cortex
perceives smell
located in temporal lobe
association area identifies smell
285
vestibular cortex
gives a sense of balance
| located in insula
286
visceral cortex
located in insula
| for crude sense of organ pain
287
Primary auditory cortex
Receives information from ears to produce sound
288
Primary auditory cortex location
In the superior margin of the temporal lobe
| Just beneath lateral sulcus
