Nervous System Flashcards
(244 cards)
1
Q
What are the 2 types of nervous tissue cells?
A
1) Neurons
2) Glia
2
Q
What are neurons?
A
Specialized cells for generating and propagating impulses across cells
3
Q
What are glia cells?
A
Support cells of the NS
4
Q
What is the basic cell of nervous tissue?
A
Neurons
5
Q
What 4 structures make up a neuron?
A
1) Dendrites
2) Cell body
3) Axon
4) Axon terminal
6
Q
Where does an axon commonly terminate, and what does it form?
A
Terminates on a neuron forming a synapse
7
Q
What is a synapse?
A
The site of signal transmission between neurons
8
Q
Most synapses are ______
A
Chemical
9
Q
Where are astrocytes found?
A
White and gray matter
10
Q
What do astrocytes secrete?
A
Growth factors
11
Q
What is the function of astrocytes?
A
Physical, metabolic, and structural support
12
Q
What 3 types of cells make up glia?
A
1) Astrocytes
2) Oligodendrocytes
3) Microglia
13
Q
What is the function of oligodendrocytes?
A
Provide myelin sheaths around axons
14
Q
What are microglia?
A
Macrophages of the NS
15
Q
What is the function of microglia?
A
Protect against viruses, bacteria, and tumor cells
16
Q
When are microglia cells activated?
A
During inflammation in the CNS
17
Q
What 2 types of cells make up the PNS?
A
1) Schwann cells
2) Satellite cells
18
Q
What are Schwann cells?
A
Myelin producing cells of the PNS
19
Q
What are satellite cells?
A
Support cells of the PNS found within ganglia
20
Q
How many pairs of cranial nerves are there and where are they attached?
A
12 pairs attached to the brain
21
Q
How many pairs of spinal nerves are there and where are they attached?
A
31 pairs attached to spinal cord
22
Q
What does gray matter consist of?
A
Neuronal cell bodies and dendrites
23
Q
What is gray matter the site of?
A
Synaptic connections
24
Q
What makes up the surface of the brain?
A
Gray matter
25
What is a nucleus (CNS)?
A collection of neuronal cell bodies that have a similar function
26
What does white matter consist of?
Axons
27
What constitutes the "wiring" of the brain?
White matter
28
What is a fasciculus?
A bundle of axons of similar functions and connections
29
What is the corpus callosum?
The largest fasciculus that connects the left and right cerebral hemispheres
30
What are the 3 main sections of the brain?
1) Forebrain
2) Midbrain
3) Hindbrain
31
What are 2 main principles of the NS?
1) Bilateral symmetry and "decussations"
| 2) "Maps" within the brain
32
What are decussations?
Descending motor tracts that start on the right and cross over to the left
33
What is the sensory homunculus?
A sensory map of the body in the rain that includes pain, temp., touch, proprioception, and vibration
34
What is the largest section of the brain?
Forebrain
35
What is the forebrain divided into?
Telencephalon (cerebrum) and diencephalon
36
What is the midbrain?
Short, narrow "stalk" that connects forebrain and hindbrain
37
What 3 sections does the hindbrain consist of?
1) Pons
2) Cerebellum
3) Medulla
38
What does the telencephalon consist of?
- Cerebral cortex (gray matter)
- White matter (axons)
- Ventricles
- Basal ganglia / nuclei
39
What are the 4 lobes of the brain?
1) Frontal
2) Parietal
3) Temporal
4) Occipital
40
What does functional localization mean?
Different sites of the brain have different functions
41
What does "contralateral nature of motor and sensory cortex" mean?
Left brain corresponds to right brain and vice versa
42
What is the cerebral cortex connected to?
Thalamus and spinal cord
43
What does the frontal lobe control?
Movements, behaviour, speech, and decision making
44
What separates the frontal and parietal lobe?
Central sulcus
45
What is the site of the primary motor cortex?
Pre-central gyrus
46
What is the pre-central gyrus responsible for?
Activating motor neurons of the spinal cord on the opposite side of the body
47
What is the site of the primary somatosensory cortex?
Post-central gyrus
48
What does the parietal lobe control?
Somatosensory info -- pain, temperature, proprioception, and interpretation of sensory input
49
What separates the parietal and occipital lobes?
Parietoccipital sulcus
50
What is the site of the primary visual cortex?
Gyri on medial surface of occipital lobe
51
What is the site of the primary auditory cortex?
Gyri on floor of lateral sulcus of temporal lobe
52
What is the site of the primary olfactory cortex?
Inferior surface of temporal lobe
53
What lobe is the hippocampus contained within?
Temporal
54
What is the function of the hippocampus?
Memory formation
55
What is the function of basal nuclei?
Regulate motor activity
56
What is the diencephalon?
Area between cerebrum and midbrain
57
What does the diencephalon make up?
Thalamus and hypothalamus
58
What does the diencephalon form and where?
The wall of the 3rd ventricle between the 2 lateral ventricles of the cerebral hemispheres and 4th ventricle
59
What is the MOTOR function of the diencephalon?
Regulates motor activity via connections with basal nuclei and cerebral cortex
60
What part of the brain regulates autonomic NS activity?
Hypothalamus
61
Where is all sensory info (except smell) processed and then where is it relayed?
Processed in thalamus and relayed to cerebral cortex
62
What 2 cranial nerves are found in the midbrain?
CN 3 (occulomotor) and CN 4 (trochlear)
63
What is the midbrain the site of?
Substantia nigra and reticular formation
64
What is the reticular formation important for?
Consciousness and arousal
65
What makes up the brainstem?
Midbrain, pons, and medulla
66
What is the largest section of the hindbrain?
Pons
67
What is the pons made up of?
- Fibres
- Cranial nerve nuclei and RF
- Pontine nuclei
68
What is the medulla made up of?
- Fibres
- Cranial nerve nuclei (9, 10, and 12)
- Reticular formation
69
Where is the brainstem located?
Between diencephalon and spinal cord
70
Where is the brainstem connected to the diencephalon?
Anterior margin of tentorium cerebelli
71
What 3 things does the brainstem contain?
1) Fibre tracts (white matter)
2) Cranial nerve nuclei (gray matter)
3) Other nuclei related to cerebellar function and consciousness
72
What is the cerebellum important for?
Maintaining equilibrium and fine motor coordination
73
What are the 3 membranous layers that cover the brain and spinal cord?
1) Dura mater
2) Arachnoid mater
3) Pia mater
74
What are the functions of the membranous layers?
Protection and compartmentalization of cranial cavity
75
What is dura made of?
Collagen
76
What is dura close to?
Bone
77
What is arachnoid close to?
Dura
78
What is the size of the layer of dura in the cranium?
Dense
79
What is the size of the layer of arachnoid in the cranium?
Thin
80
What is the thinnest and innermost layer of the membranous layers?
Pia
81
What kind of space are the cranial epidural and subdural spaces?
A potential space
82
What is the cranial epidural space inbetween?
Dura and skull
83
What is the cranial subdural space inbetween?
Dura and arachnoid
84
What is epidural hematoma?
When the middle meninigeal artery lies between dura and skull, which will leak blood and cause dura to separate from skull
85
What is subdural hematoma?
When vessles passing between arachnoid and dura leak blood into subdural space
86
Where is the subarachnoid space?
Between arachnoid and pia
87
What is the subarachnoid space filled with?
Cerebrospinal fluid (CSF)
88
Are blood vessels present in the subarachnoid space?
Yes
89
How many cavities are there in the ventricular system and what are they filled with?
4 cavities filled with fluid
90
What drains into the 3rd ventricle and through what?
- 2 lateral ventricles
| - Through inter-ventricular foramina
91
What drains into the 4th ventricle and through what?
- 3rd ventricle
| - Through midline cerebral aqueduct
92
What parts of the brain make up the floor of the 4th ventricle?
Pons & medulla
93
What part of the brain makes up the roof of the 4th ventricle?
Cerebellum
94
What part of the brain makes up the wall of the 3rd ventricle?
Diencephalon
95
What is the flow of the ventricular system?
2 lateral ventricles into midline 3rd ventricle, which drains into 4th ventricle via cerebral aqueduct
96
What does the 4th ventricle drain into?
Subarachnoid space
97
What produces cerebralspinal fluid?
Choroid plexus
98
How much CSF is produced per day?
About 500 mL
99
What is the choroid plexus?
Highly vascularized tissue found within all 4 cerebral ventricles
100
What does CSF look like and where is it derived from?
Clear fluid derived from plasma of the choroid plexus
101
What is the choroid plexus made of?
Specialized epithelial cells
102
How is CSF absorbed into the blood?
Arachnoid granulations in venous sinuses
103
What is hydrocephalus caused by?
CSF production being greater than absorption
104
What are 3 functions of CSF?
1) Provide protection and buoyancy to brain
2) Maintain consistency of environment for brain tissue
3) Remove cellular waste
105
How is CSF drained, and where is it drained from and to?
Drained by arachnoid villi from subarachnoid space into venous sinuses
106
What are arachnoid villi?
Tufts of arachnoid that extend through dura into venous sinus
107
What is the function of CSF?
Transport CSF from villi and granulations into venous blood
108
When does production of CSF stop?
Never
109
Where are arachnoid villi most numerous?
Superior sagittal sinus
110
What supplies oxygen to the brain?
Internal carotid and vertebral arteries
111
Does the internal carotid provide anterior or posterior oxygen circulation?
Anterior
112
Do the vertebral arteries provide anterior or posterior oxygen circulation?
Posterior
113
Where does the internal carotid provide circulation?
Telencephalon and diencephalon
114
Where do the vertebral arteries provide circulation?
Cervical spinal cord, brainstem, cerebellum, occipital and temporal lobes, and posterior and inferior cerebrum
115
What are the 3 major branches of the internal carotid?
1) Posterior communicating
2) Anterior cerebral
3) Middle cerebral
116
What does the posterior communicating branch do?
Connects anterior and posterior arterial supplies
117
Where is the anterior cerebral branch found?
Medial and superior surfaces of frontal and parietal lobes
118
What connects the 2 anterior cerebral branches?
Anterior communicating
119
What can be caused by an occlusion of the anterior cerebral?
Sensory and motor deficits of the lower limbs of the contralateral body
120
Where is the middle cerebral branch found?
Lateral cortical and sub cortical areas
121
What does the middle cerebral branch do?
Supplies large portion of motor and pre-motor areas in the frontal, parietal, and temporal lobes
122
What may be caused by an occlusion of the middle cerebral branch?
Sensory and motor deficits in the upper limbs and head of the contralateral body
123
What do the vertebral arteries enter, and what do they form once in?
Enter cranium and form the single basilar artery
124
What does the basilar artery ascend along?
Pons
125
What does the basilar artery split into?
Left and right posterior cerebral arteries
126
What do the posterior cerebral arteries supply?
Occipital lobe and inferior surface of temporal lobe
127
What connects the posterior cerebral and anterior circulation arteries?
Posterior communicating artery
128
What is the anterior spinal artery?
Midline artery that descends along the anterior medial sulcus of the medulla and spinal cord
129
What does the CNS require for neurons to stay alive?
Uninterrupted flow of blood and constant energy
130
What causes a stroke?
Interrupted blood supply to the brain
131
What system are typically involved in strokes?
Arterial system
132
What is an ischemic stroke?
An occlusion of vessel
133
What is a hemorrhagic stroke?
When a vessel bursts; involves smaller vessels under chronic hypertension
134
What is a sinus?
A channel carrying deoxygenated blood to internal jugular veins
135
What is a sinus functionally similar to?
A vein
136
Where does all venous blood in the brain drain into?
A venous sinus
137
What is a difference between sinuses and arteries?
Sinuses have lower pressure than arteries
138
What are the 3 midline sinuses that carry the majority of the brains venous blood?
1) Superior sagittal sinus
2) Inferior sagittal
3) Straight sinus
139
Where is the superior sagittal sinus?
Superior margin of falx cerebri
140
Where is the inferior sagittal sinus?
Inferior margin of falx cerebri
141
What does the inferior sagittal sinus flow into?
Straight sinus
142
Where is the straight sinus?
Junction of falx cerebri and tentorium cerebelli
143
What are the 3 major paired sinuses?
1) Transverse sinus
2) Inferior petrosal sinus
3) Sigmoid sinus
144
What does the sigmoid sinus join with and what does it form?
Joins with inferior petrosal to form internal jugular vein
145
What do superficial cerebral veins drain into and what is the rest of the flow?
Drain into superior sagittal sinus --> confluence of sinuses --> transverse sinus --> sigmoid sinus --> internal jugular
146
What is the function of the internal jugular vein?
Drain blood from the brain and return it to the heart
147
What do the deep cerebral veins drain into and what is the rest of the flow?
Drain into inferior sagittal sinus --> straight sinus --> transverse sinus --> sigmoid sinus --> internal jugular
148
How many cranial nerves are there and what do they innervate (grand scheme)?
12 pairs that innervate head and neck, as well as thorax and abdomen
149
Which cranial nerves arise from the midbrain?
3 - occulomotor & 4 - trochlear
150
Which cranial nerves arise from the pons?
5 - trigeminal, 6 - abducens, 7 - facial, & 8 - vestibulocochlear
151
Which cranial nerves arise from the medulla?
9 - glossopharyngeal, 10 - vagus, 11 - spinal accessory, & 12 - hypoglossal
152
What is an acronym to remember the cranial nerves?
Oh Once One Takes The Anatomy Final Very Good Vacations Are Heavenly
153
Which cranial nerves have only sensory functions?
1 - olfactory, 2 - optic, and 8 - vestibulocochlear
154
Which cranial nerves have only motor functions?
3 - occulomotor, 4 - trochlear, 6 - abducens, 11 - spinal accessory, & 12 - hypoglossal
155
Which cranial nerves have sensory and motor functions?
5 - trigeminal, 7 - facial, 9 - glossopharyngeal, & 10 - vaugs
156
What is the function of the olfactory nerve?
Carry olfactory info from olfactory epithelium through the foramina of cribiform plate
157
What is the function of the optic nerve?
Carries visual info from retina through optic canal
158
What is the function of the vestibulocochlear nerve?
Carries balance and hearing from inner ear (cochlear and vestibular apparatus) through the internal auditory meatus
159
What is the function of the occulomotor nerve?
Innervate intrinsic muscles and 4 of the 6 extrinsic muscles of the eye
160
What is the function of the trochlear nerve?
Innervate superior oblique (pulls down eye when adducted)
161
What is the function of the abducens nerve?
Innervate lateral rectus (abducts eye)
162
What is the function of the spinal accessory nerve?
Innervate steinocleidomastoid (rotate head) and trapezius (shrug shoulders)
163
What is the function of the hypoglossal nerve?
Innervate intrinsic and extrinsic muscles of tongue (sticking out tongue)
164
What does the spinal accessory nerve leave the cranium through?
Jugular foramen
165
What does the hypoglossal nerve leave the cranium through?
Hypoglossal canal
166
What are the 3 branches of the trigeminal nerve and what is its simplified function?
- Somatosensation of the face
1) Ophthalmic nerve
2) Maxillary nerve
3) Mandibular nerve
167
What is the function of the ophthalmic branch of the trigeminal nerve?
Somatosensory from cornea, nose, and forehead
168
What is the function of the maxillary branch of the trigeminal nerve?
Somatosensory from maxilla, upper lip, teeth, and hard palate
169
What are 2 functions of the mandibular branch of the trigeminal nerve?
- Somatosensory from mandible, lower lip, teeth, and anterior 2/3 of tongue
- Motor to muscles of mastication (chewing)
170
What is the sensory function of the facial nerve?
Taste and anterior 2/3 of tongue
171
What are the motor functions of the facial nerve?
- Muscles of facial expression
| - All glands of face / oral cavity EXCEPT PAROTID
172
What is the sensory function of the glossopharyngeal nerve?
Taste and somatosensation of posterior 1/3 of tongue
173
What are the motor functions of the glossopharyngeal nerve?
- Assist in swallowing
| - Parotid gland
174
What are the sensory functions of the vagus nerve?
- Taste (epiglottis)
| - Visceral sensory from respiratory tract and viscera
175
What are the motor functions of the vagus nerve?
- Swallowing and speech
| - Respiratory tract, heart, esophagus, and intestines
176
How many layers of meninges are there and what are they called?
3
1) Dura mater
2) Arachnoid
3) Pia mater
177
List the meninges layers from outermost to innermost
Dura, arachnoid, pia
178
At what vertebrae does the dura end?
S2
179
What does dura look & feel like?
Tough, fibrous, and continuous with dura of brain
180
Where is the REAL epidural space, and what does it contain?
- Between dura and vertebral bones
| - Contains connective tissue, fat, and veins
181
What is the arachnoid meninge layer adherent to?
Dura
182
At what vertebrae does the arachnoid end?
S2
183
Where is the subarachnoid space and what does it contain?
- Between arachnoid and pia
| - Contains CSF
184
What is the lumbar cistern and what is it used for in medicine?
- Space between L1 and S2
| - Used to get a sample of CSF without possibility of damaging the spinal cord
185
What does pia mater adhere to?
Spinal cord
186
At what vertebrae does the pia end at?
S2
187
What makes up the sac that contains the spinal cord?
Dura
188
What is dura NOT attached to?
Vertebral bones
189
What kind of ligaments attach spinal cord to dural sac?
Denticulate ligaments
190
Where does the dura sac begin and end?
- Begins at foramen magnum
| - Ends at S2
191
At what vertebrae does the spinal cord end?
L1 - L2 (the conus medullaris)
192
What is the cauda equina?
Lumbar, sacral, and coccygeal nerve roots that extend to exit the dural sac
193
What tethers the end of the spinal cord to dural sac?
Filum terminale (extension of pia)
194
What is the cervical enlargement and between which vertebrae is it found?
- Site of innervation of arm
| - C4 - T1
195
What is the lumbosacral enlargement and between which vertebrae is it found?
- Site of innervation of leg
| - L2 - S3
196
Describe the differences between roots in the cervical region and roots in the lumbosacral region
- Roots in cervical region are short and horizontal
| - Roots in lumbosacral region are long and vertical (cauda equina)
197
What is the function of the dorsal horn?
It processes and relays sensory info to the brain
198
How does sensory information enter the spinal cord?
Dorsal root
199
What kinds of fibres does the dorsal root contain?
Afferent (sensory)
200
Where are ALL cells bodies of sensory neurons located?
Dorsal root ganglion
201
What is the function of the ventral horn?
Projects signals to muscle through large motor neurons via the ventral root
202
What are motor neurons innervated by?
Descending fibres carried in white matter
203
What does white matter consist of?
Nerve fibres, neuroglia, and blood vessels
204
Why does white matter appear white?
Fibres are myelinated
205
What 3 locations do fibres arise from?
Cell bodies in:
1) Brain
2) Spinal cord
3) Periphery
206
What kind of axons do fibres in the brain contain?
Descending axons from cerebrum and brainstem
207
What kind of axons do fibres in the spinal cord contain?
Ascending axons from gray matter
208
What kind of axons do fibres in the PNS contain?
Ascending axons from dorsal root ganglion
209
What direction does sensory info travel?
Up the cord to the brain
210
What area of the spinal cord will have the greatest number of sensory fibres?
Top
211
What direction does motor activity travel?
Down the cord to the neurons in the gray matter
212
What area of the spinal cord will have the greatest number of motor fibres?
Top
213
What does gray matter mainly consist of?
Neuronal cell bodies and neuroglia
214
How many pairs of spinal nerves are there?
31
215
Describe the path of spinal nerves
Leave spinal cord, pass through intervertebral foramen, and exit as peripheral nerves
216
How many pairs of cervical spinal nerves are there?
8
217
How many pairs of thoracic spinal nerves are there?
12
218
How many pairs of lumbar spinal nerves are there?
5
219
How many pairs of sacral spinal nerves are there?
5
220
How many pairs of coccygeal spinal nerves are there?
1
221
What attaches spinal nerves to the cord?
A ventral root and a dorsal root
222
What innervates skeletal muscle?
Motor neurons (cell bodies in the ventral horn)
223
How do action potentials enter the CNS?
Dorsal roots of spinal nerves
224
Name 3 stimuli that the sensory system is capable of detecting
1) Mechanical
2) Pain
3) Temperature
225
What are 2 examples of mechanoreceptors?
1) Neuromuscular spindles
| 2) Golgi tendon organs
226
What do neuromuscular spindles detect?
Changes in length
227
What do golgi tendon organs detect?
Tension in tendons
228
Where are cell bodies of sensory neurons of the PNS found?
Dorsal root ganglion
229
What structures are supplied by spinal nerves?
Myotomes and dermatomes
230
Is a spinal nerve sensory, motor, or mixed?
Mixed
231
What are myotomes?
Muscles innervated by motor fibres of a spinal nerve
232
What is a dermatome?
An area of skin innervated by sensory fibres of a spinal nerve
233
Name 2 consequences of peripheral nerve injury
1) Muscle degeneration
| 2) Loss of sensitivity in a dermatome
234
What are 3 target tissues of the autonomic nervous system?
1) Cardiac muscle
2) Smooth muscle
3) Glands
235
What is the cell body of the first neuron in the CNS referred to as?
Pre-ganglionic neuron
236
What is a ganglion the site of?
Connection between the pre- and post-ganglionic neuron
237
What are the 2 divisions of the ANS, and do they have similar or opposing functions?
1) Sympathetic
2) Parasympathetic
- Opposing
238
When is the sympathetic nervous system activated?
During the "fight or flight" response
239
Where are pre-ganglionic cell bodies of the sympathetic NS located?
Thoracic and lumbar segments of spinal cord
240
Where are pre-ganglionic cell bodies of the parasympathetic NS located?
Brainstem and sacral levels of spinal cord
241
Where are parasympathetic ganglia located?
Near the target tissue
242
When is the parasympathetic NS most dominant?
At rest
243
What happens when both the branches of the ANS innervate a muscle?
One branch will cause contraction and the other will causes relaxation
244
What part of the brain is a major regulator of the ANS?
Hypothalamus
