Nervous System Flashcards
(279 cards)
1
Q
What is a system?
A
collection of different organs and tissues that has a specific function
2
Q
What is the nervous system made up of?
A
a network of nerve cells (neurons and fibres)and their supporting cells
3
Q
What does the nervous system basically do?
A
transmit nerve impulses between different parts of the body
4
Q
What is the basic function of the nervous system?
A
allows sentient organisms to live effectively in their environment
5
Q
What are ganglia?
A
collections of cell bodies
6
Q
What are the 4 key functions of the nervous system?
A
sense and monitor environment
respond, react and move around environment
integrate, process and store information
maintain internal stasis of the body
7
Q
What tissues and cells does sensing and monitoring the environment involve?
A
sensory tissues and organs, sensory nerves
8
Q
What cells and tissues are involved in responding to and moving around the environment?
A
motor nerves and muscles
9
Q
What cells and tissues are involved in maintaining internal stasis of the body?
A
motor nerves, smooth/cardiac muscle and glands
10
Q
What are the two locations of the nervous system?
A
central nervous system and peripheral nervous system
11
Q
What is the CNS comprised of?
A
brain and spinal chord
12
Q
What is the PNS comprised of?
A
all nerves that are not found in the brain/spinal chord
13
Q
What can the sensory nervous system also be known as?
A
afferent
14
Q
What can the motor nervous system also be known as?
A
efferent
15
Q
What is the difference between somatic and autonomic nervous systems?
A
somatic is voluntary and autonomic is involuntary
16
Q
What are glia?
A
supporting cells of CNS and PNS
17
Q
How does regeneration of nerves differ between CNS and PNS?
A
CNS- nerves do not regenerate after injury, there is no secretion of growth factors and inhibitory factors are actually released
PNS- nerves regenerate well after injury
18
Q
What are the 2 branches of the autonomic nervous system?
A
sympathetic and parasympathetic
19
Q
What does the sympathetic nervous system do?
A
fight of flight mechanism, speeds things up and diverts blood where it is needed (e.g. away from digestive system towards muscles)
20
Q
What does the parasympathetic nervous system do?
A
rest and digest mechanism, slows everything down, diverts blood back to slower areas (e.g. towards digestive system)
21
Q
What main divisions of the nervous system are the sympathetic and parasympathetic systems associated with?
A
CNS and PNS
22
Q
What is a neuron?
A
the functional unit of the nervous system
23
Q
What 3 types of neuron are there?
A
sensory, motor and interneurons
24
Q
What are neurons specialised to do?
A
detect and react to stimuli
25
What do neurons generate, conduct and transmit?
nerve impulses
26
What are the 3 main areas on a neuron?
axon, dendrites and terminal synapses
27
How does the signal flow through a neuron?
dendrites-axon-terminal synapse
28
what do neuroglia do?
surround neurons
29
What do neurons use synapses for?
to communicate with other neurons or effector target cells
30
Where are the 3 main locations of synapses?
axon to dendrite, axon to cell body, axon to axon
31
Basically describe how a synapse works?
nerve impulse reaches terminal, stimulates the release of synaptic vesicles containing neurotransmitter. These leave the cell by exocytosis, cross the synaptic cleft to receptors on next cell surface
32
What is mylination?
surrounding of axon by glial cells to improve rate of conduction
33
What is the node of ranvier?
unmylinated area of nerve cells
34
Which cells are involved in mylination in the CNS?
oligodendrites
35
Whic cells are involved in mylination in the PNS?
schwann cells
36
How are axons mylinated differently in CNS and PNS?
CNS- each cell wraps around a different part of the axon
| PNS- axon is mylinated by single cell that is wrapped/spiralled around
37
What is the CNS housed within?
bone
38
What bones are the brain and spinal cord housed in?
cranium and vertebrae
39
What is the name for the 3 layers of tissue which surround the CNS?
meninges
40
What are the 3 layers of meninges?
dura mater, arachnoid mater, pia mater
41
What is the dura mater like?
tough, outer layer of meninges
42
What is the arachnoid mater like?
web like appearance, middle layer of meninges
43
What is the pia mater like?
pink in colour, sits directly on top of spinal cord and bran, thinnest layer
44
What do the meninges do?
support and protect CNS and produce cerebral spinal fluid
45
What do spaces between meningeal layers house?
CSF and blood vessels
46
Where is the grey and white matter located in the spinal cord and what do they contain?
grey: houses cell bodies, located inside white matter which contains axons
47
Where is the grey and white matter located in the brain and what do they contain
grey: houses cell bodies and is located outside of the white matter which contains axons
48
Why is white matter white?
mylination of axons
49
Where does the spinal cord exit the brain?
at the foramen magnum
50
What is the foramen magnum?
hole at the bottom of the skull through which the spinal cord exits
51
Where does the spinal cord begin?
at the exit of the brain
52
What are the 5 sections of the spine?
cervical, thoracic, lumbar, sacral, coxygeal
53
What do nerves from the cervical spine lead to?
upper limbs/forelimbs
54
What do nerves from the thoracic spine lead to?
body wall and skin
55
What do nerves from the lumbar spine lead to ?
lower/hind limbs
56
What do nerves from the sacral spine lead to?
lower/hind limbs
57
Why is the cord not uniform in thickness?
increases in thickness in areas which correspond with limbs, increased neurons to the area
58
Where is the spinal cord thicker?
lumbar/sacral and cervical regions
59
What shape is the end of the spinal cord?
cone shaped
60
What is the name for the end of the spinal cord?
conus medullaris
61
At the end of the spinal cord what is the name of the nerves which continue in the vertebrae?
cauda equina
62
What is the filum terminale?
attachment of pia mater thread to the coccyx to anchor the spinal cord and cauda equina
63
what is the number of nerve pairs in each region often the same as?
the number of vertebrae in that region
64
How many pairs of spinal nerves are there in humans?
31
65
How many pairs of cervical nerves do all mammals have?
8
66
What happens to nerves in the thoracic region when they leave the spinal cord?
come out horizontally and don't touch any other nerves
67
What are plexi?
groups of nerves that join together outside the spinal cord to form bigger nerves
68
What are 3 plexi in the mammalian body?
brachial plexus, lumbar plexus, sacral plexus
69
What do cranial nerves form part of?
PNS
70
How many pairs of cranial nerves are there?
12
71
Where do most cranial nerves originate from?
midbrain
72
What arteries make up the circle of willis?
clockwise from rostral end: anterior communicating artery, anterior cerebral artery, posterior communicating artery, posterior cerebral artery
73
Why is the circle of willis so important?
collateral blood flow, if one artery becomes blocked the blood can still flow to the brain
74
What are venous sinuses?
channels of venous blood that run between layers of dura
75
What two layers of dura are venous sinuses found between?
periostial and meningial
76
Where is the superior saggital sinus located?
over the top of the brain, on the midline
77
What does the sigmoid sinus do?
drains all blood from transverse sinus into internal jugular vein
78
What are the ventricles of the brain?
chambers within the brain
79
What do ventricles in the brain produce?
CSF
80
What are the 4 ventricles of the brain?
2 lateral ventricles that drain in to the 3rd ventricle in the midline, 4th ventricle is in the hindbrain
81
Where does cerebral spinal fluid enter the spinal cord and sub arachnoid space?
lateral and median apatures
82
What is CSF produced by that is found within all the ventricles of the brain?
choroid plexus
83
Where is CSF absorbed back into the blood stream?
venous sinuses at arachnoid villi
84
What does the ectoderm in an embryo go on to create?
skin and nervous system
85
What does ectoderm differentiate into?
ectoderm (skin) and neuroectoderm (neural tube)
86
What are neural crests the margins of?
neuroectoderm
87
What happens when neural crests meet in the mid line?
form a tube (neural tube)
88
What happens to neural crest cells once they separate from neuroectoderm?
migrate across embryo to differentiate into multiple different neural cells
89
What 7 structures do neural crest cells differentiate into?
```
sympathetic ganglia
dorsal root ganglion (neural tube)
adrenal medulla
intrinsic nerve plexuses
ondontoblasts
melanocytes
tissues of iris
```
90
What are the edges of the neural plate called?
neural folds
91
What do neural folds meet in the midline to form?
neural tube
92
what are the holes at each end of the neural tube known as?
cranial or caudal neuropores
93
Once the neuropores are closed what structures can begin to form?
brain and spinal cord
94
What does the closed neural tube then undergo to form the 3 cranial vesicles?
massive growth, swelling and folding
95
How many cranial vesicles are there initially?
3
96
What are the names of the 3 vesicles?
forebrain, midbrain and hindbrain
97
What does the lumen of the neural tube form?
ventricles of brain
98
At what week are 5 cranial vesicles formed?
week 5
99
What is the correct term for the forebrain?
prosencephalon
100
what is the correct term for the midbrain?
mesencephalon
101
what is the correct term for the hindbrain?
rhombencephalon
102
What are the names of the vesicles that the prosencephalon splits into?
telencephalon and diencephalon
103
What is formed in the telencephalon?
cerebral hemispheres and lateral ventricles
104
what is formed in the diencephalon?
thalamus, hypothalamus, pituitary gland and the 3rd ventricle
105
what two ventricles form in the rhombencephalon?
metencephalon and myelencephalon
106
what is formed in the metencephalon?
pons and cerebellum
107
what is formed in the myelencephalon?
medulla oblongata
108
from which vesicle does the optic vesicle originate?
diencephalon
109
What happens to the lumen of the mesencephalon?
narrows to form cerebral aqueduct
110
How many different fibre types are there in the brain?
3
111
How are the fibre types in the brain named?
According to their origin and destination
112
Are brain fibres myelinated or non myelinated?
Myelinated
113
What’s re the 3 types of brain fibre?
Association, projection. Commisural
114
What do association fibres do?
Span cortical regions within the same hemisphere
115
Give 2 examples of where association fibres may be found
Cinglugate gyrus
116
What do projection fibres link?
Cortex to other regions outside the cortex, sun cortical structures
117
Give an examples of where projection fibres are found
Internal capsule and corona radiata
118
What are commisural fibres?
Communicate between two hemispheres
119
Give 2 examples of where commisural fibres are located
Corpus callosum and anterior commisure
120
What is a plexus?
Region of the peripheral nervous system where several nerves arising from the spinal cord join
121
What do nerves in a plexus subsequently divide into?
Individual nerves
122
What are individual nerves that split from plexi named for?
Destination and function
123
What does a plexus allow?
Nerve fibres that originated in one nerve can be distributed into another
124
What are the types of plexus?
Spinal plexuses and autonomic plexuses
125
What is a spinal plexus?
Where spinal nerves containing mixed motor and sensory fibres join
126
What is an example of a spinal plexus?
Brachial plexus
127
What is an autonomic plexus?
Where splanchich nerves containing autonomic fibres join
128
Give an example of an autonomic plexus
Myenteric plexus
129
What other structure can a plexus recur to?
A group of blood vessels
130
What is controlled by spinal plexuses?
Skeletal muscles and skin
131
What is controlled by autonomic plexuses?
Smooth muscle
132
What nerve roots is the brachial plexus formed from?
Nerve roots of spinal nerves from C5, C6, C7, C8, T1
133
Which nerve roots join to form nerve trunks?
C5, C6 and C8, T1
134
What happens to the nerve trunks in a brachial plexus?
Divides into 2 and then reforms/ joins forming cords
135
What do nerve cords which originate from trunks in nerve plexi become?
Individual nerve branches (e.g. radial or ulnar nerves)
136
What is a spinal reflex?
A relay of sensation or stimulus which brings about an appropriate, fixed reaction or motor response
137
Where do afferent nerves enter the spinal cord?
The dorsal root
138
Where do efferent nerves exit the spinal cord?
Ventral root
139
Give a brief explanation of a reflex arc
Stimulus sensed, sensory nerve, synapse, motor neuron, effector
140
What happens during reciprocal innervation?
Stimulus, sensory nerve, inhibitory interneuron. This leads to no opposition of movement required by reflex
141
What does reciprocal innervation basically do?
Stops the antagonist of the reflex movement from being activated so that the reflex works
142
What is the spinal cord important in?
conveying sensory information from the body to the brain so that it can be experienced as sensation
also conveys information regarding appropriate motor responses coordinated by the brain
143
where are spinal tracts found?
white matter of the spinal cord
144
are spinal tracts myelinated or non-mylinated?
myelinated as located in white matter
145
what are the 2 types of spinal tracts?
ascending and descending
146
What do ascending spinal tracts do?
transfer sensory information towards the brain
147
What region of the spinal chord are ascending spinal tracts found in?
dorsal
148
what do descending spinal tracts do?
transfer motor information back towards the peripheral nervous system
149
what region of the spinal chord are descending spinal tracts found in?
tend to be found in the ventral regions of the cord
150
Why does each tract contain different nerve fibre types?
because they carry different information types
151
what is a single spinal tract called?
fasciculus
152
What is a funinculus?
Column of white matter tissue
153
What are the 3 main groups of funinculus?
Dorsal or posterior, lateral, ventral or anterior
154
what areas do motor somatic nerves go to?
skeletal muscle
155
What does the corticospinal pathway do?
Motor information from the motor cortex to the spinal cord, out into periphery to relevant skeletal muscles
156
What does ipsilateral mean?
Same side of the nervous system
157
What does converlateral mean?
Refers to the opposite side of the nervous system
158
what are the 2 branches of the sensory afferent nerves?
general and specialised
159
What sides is the nervous system divided into?
Left and right
160
What a nociceptors?
Receptors that detect noxious stimuli
161
What do autonomic afferents and efferents arise from and go to?
the viscera
162
Give 2 examples of areas sensory somatic nerves arise from
skin/eyes/ear
163
what areas do motor somatic nerves go to?
skeletal muscle
164
What is the somatic nervous system sometimes known as?
voluntary
165
What are the 2 components of spinal nerves?
motor and sensory
166
what are the 3 nerve types found in the somatic nervous system?
afferent sensory, efferent motor and interneurons
167
what are the 2 branches of the sensory afferent nerves?
general and specialised
168
What do general sensory afferent nerves detect?
touch, vibration etc
169
what do specialised sensory afferent nerves detect?
special senses (e.g. sight, hearing)
170
What do autonomic afferents and efferents arise from and go to?
the viscera
171
Which of the special senses are autonomic?
taste and smell
172
what are the functions of the somatic nervous system?
involved in the detection of stimuli from the external environment and control of skeletal muscles
173
What are spinal nerves named according to?
the region from which they emerge
174
what does the ventral rami do?
supplies muscles and skin associated with limbs and trunk
175
What can be formed from ventral rami?
plexuses
176
How many spinal nerve pairs do humans have in total?
31
177
How many cervical nerve pairs do all mammals have?
8
178
How many spinal nerve pairs do cats and dogs have in total?
36
179
how many spinal nerve pairs do horses have in total?
42
180
what are dermatomes?
area of skin supplied by the afferent fibres of one single spinal nerve
181
what are myotomes?
group of skeletal muscles supplied by efferent fibres of one single spinal nerve
182
What does the T10 dermatome cover?
the umbilicus, often where pain originates during appendicitis
183
What does the L3 and L4 myotome supply?
quadriceps
184
What are myomeres?
adjacent blocks of skeletal muscle tissues separated by connective tissue
185
In what species are myomeres often seem?
fish (e.g. salmon)
186
What does the visceral nervous system monitor and control?
cardiac muscle, smooth muscle and glands
187
What is the motor division of the viscera known as?
autonomic nervous system
188
what are the 2 branches of the autonomic nervous system?
sympathetic and parasympathetic
189
What does the sympathetic nervous system control?
fight/flight
190
What does the parasympathetic nervous system control?
rest and digest
191
Is the sympathetic or parasympathetic system more widespread in the body?
sympathetic
192
What are the 2 types of visceral neurons?
general visceral afferent and general visceral efferent
193
where does the visceral nervous system synapse?
in the ganglia
194
Where is the cell body of presynaptic neurons of the visceral nervous system located?
cell body is in the grey matter of spinal cord
195
where are the postsynaptic neurons of the visceral nervous system located?
cell body in ganglion and axon outwards of this
196
Do ganglia vary between sympathetic and parasympathetic systems?
yes
197
Where are ganglia located in the sympathetic nervous system?
close to the spinal column
198
Where are ganglia located in the parasympathetic nervous system?
proximal to target organ
199
where are pre-vertebral ganglion located?
in front of the spinal cord
200
where are para vertebral ganglion located?
next to the spinal cord
201
What part of the sympathetic nervous system do the paravertebral ganglia from?
sympathetic chain
202
are there any synapses in the sympathetic chain?
no
203
What 2 locations do sympathetic neurons originate in?
thoracic and lumbar regions
204
What are splanchnic nerves?
nerves heading towards sympathetic /visceral structures, usually sympathetic nerves
205
Do parasympathetic nerves have a chain like the sympathetic chain?
no
206
where do the parasympathetic nerves originate from?
cranial and sacral regions
207
What 4 cranial nerves are parasympathetic?
3, 7, 9 and 10
208
What number cranial nerve is the vagus nerve?
10
209
Where are ganglia located in the parasympathetic nervous system?
close to/within the target organ
210
Do parasympathetic nerves join with spinal nerves?
no
211
In non-human mammals where is the vagus trunk formed of and what 2 nerves is is formed of?
in the neck adjacent to oesophagus
| sympathetic nerve and vagus nerve
212
What is ischemia?
lack of blood supply
213
what is an ischemic stroke?
occlusion of a blood vessel in the brain by a clot
214
How can symptoms of nervous damage differ?
depends on site of injury and therefore the type of nerve fibre that has been damaged
215
What are common symptoms of sensory nerve damage?
partial/complete loss of sensation
| parasthesia (pins and needles)
216
what is parasthesia?
pins and needles
217
What are common symptoms of motor nerve damage?
weakness/paralysis of muscles
change in muscle tone (rigidity and power)
fascultations (twitching)
218
What is tetraplegia?
complete or partial paralysis of all 4 limbs
219
what is paraplegia?
paralysis below bracial plexus so arms/forelimbs function but legs/hindlimbs do not
220
What is hemiplegia?
Damage to one of the cerebral hemispheres that leads to paralysis of the side of the body it controls (opposite)
221
what can the formation of a dermoid sinus lead to?
infection within the spinal cord
222
What are 2 examples of neural tube defects?
spina bifida and anencephaly
223
What is the function of the temporal lobe?
hearing
224
What is the function of the oxypital lobe?
vision
225
what is the function of the frontal lobe?
higher mental functions/memory formation
226
What do the nerve endings of sensory nerves relate to ?
their functions
227
What are the 2 divisions of sensory neurone?
free and encapsulated
228
How does the terminus of sensory process appear in a free sensory neuron?
lacks any special ending/association
229
How do free sensory neurons increase the area monitored?
branch extensively
230
Where are free sensory neurons most often found?
in epidermis and dermal skin layers
231
How does the terminus of sensory process appear in an encapsulated sensory neuron?
enclosed in a specialised structure
232
What are 2 examples of encapsulated sensory neurons?
messiner corpuscle: light touch, in the dermis
| corpuscle of Ruffini: dual mechanoreceptor and thermoreceptor
233
Where are proprioceptors found?
within muscle/tendon
234
What is the function of proprioceptors?
show degree of strength/stretch and enables CNS to have an idea of location of limb in space
235
What is hyperalgesia?
amplification of stimulus to sensory nerves as a result of tissue damage
236
What is alodenia?
reduction of pain threshold as a result of nervous tissue damage. Non-painful stimuli may be interpreted as such
237
What are the majority of muscle fibres made up of?
extra fusal muscle fibre
238
What does extra fusal muscle fibre contain?
actin, myosin and sarcomeres
239
What do muscle fibres basically do?
lengthen and shorten muscle
240
what sort of nerves are muscle fibres innervated by?
somatic efferent neurones
241
Why does the CNS need to be receptive to the tone and stretch in muscles?
to ensure there is no damage
242
Do muscles contain a slight amount of tension even when relaxed?
yes
243
What is the name of the sensory fibres of the PNS that extend into the muscle which measure tension and stretch?
muscle spindle
244
What makes up a muscle spindle?
composed of intrafusal muscle fibre which has a sensory nerve fibre wrapped around it
245
What part of the brain is information from muscle spindles relayed to?
cerabellum
246
What happens to the frequency of action potential in muscle spindles when they stretch?
increases
247
What happens to the frequency of action potential in muscle spindles when they contract?
decreases
248
What are golgi tendon organs?
sensory fibres in tendons that attach to bone
249
What do golgi tendon organs measure?
tension recorded by tension created in muscles
250
Where are hair cells found?
in inner ear, cochlea and vestibular organs
251
What transduces signals into electrical impulses in hair cells?
deformation of hair cells by sound waves or fluid
252
What are lateral line systems?
pores on the sides of fish which are sensitive to movement in water and pressure changes
253
What parts of fish behavior do lateral line systems help with?
school behavior
254
What is echolocation?
animal emits and detects soundwaves to determine the rages between objects
255
Ho do dolphins produce and receive soundwaves during echolocation?
air enters blowhole and fills nasal sacs where it vibrates. this produces sound waves which are concentratedin the melon and emmitted as a beam into surrounding water. Vibrations received are felt in the jaw and transfurred to the middle ear where hair cells in the vestibular system are deformed
256
What do radiation receptors pick up?
light spectrum
257
What is infra red light linked to?
thermoreceptors
258
what is UV light filtered by?
human eye, retinal pigments
259
In what species are electrorecptors seen?
bony fish and monotrines
260
What is a monotrine?
mammal that lays eggs
261
what do electroreceptors produce and detect?
electric and magnetic fields
262
What would a gustatory stimulus be triggerd by?
taste
263
What sensations other than those produced by chemoreceptors lead to our experience of taste?
mechanical texture of food
| olfaction
264
What are pheremones produced by?
exocrine glands
265
What is the main taste organ?
the tongue
266
Which cranial nerves are involved in taste?
7 and 9
267
Which part of the tongue supplies cranial nerve 7?
anterior 2 thirds
268
which part of the tongue supplies cranial nerve 9?
posterior third
269
Where are tastebuds located?
crits on papilliae
270
What are tastebuds also known as?
gustatory cells
271
What parts of the tongue contain tastebuds?
valliate
foliate
fungiform
272
Which part of the tongue is involved in general sensation?
fileform
273
Where is the gustatory cortex located in the brain?
insular region between temporal and poriatal lobes deep into the lateral fissure
274
How are the olfactory nerves stimulated?
air is inhaled into nasal passages and picked up by nasal hair and mucous that line the nasal mucosa. Odorants dissolve in mucous and stimulate olfactory nerves
275
Where is the olfactory centre of the brain located?
olfactory bulb near the hippocampus
276
What is the main organ involved in pheromone detection?
jacobsen's organ/vomeronasal organ
277
Where is the vomeronasal organ located?
nasal septum
278
In what species is a vomeronasal organ found?
cats, dogs, reptiles, equines, cows
279
What varies in the usage of the vomeronasal organ between species?
how they deliver the pheromone to the organ (e.g. cats and horses inhale to a duct behind their teeth. Snakes use their tongue to gather scent and then touch the organ)
