cns Flashcards
(414 cards)
1
Q
what id the embryonic structure of the brain
A
neural tube
2
Q
primary vesicle rises to
A
secondary brain vesicle
3
Q
secondary brain vesicledivides into
A
telencephalon and diencephalon
4
Q
hindbrain forms
A
metencephalon and myelencephalon
5
Q
each 5 vesicles produce
A
major structure of the adult brain
6
Q
2 cerebral hemispheres are
A
cerebrum
7
Q
diencephalon produces
A
hypothalamus, thalamus, epithalamus, and retina of eye
8
Q
midbrain and hindbrain produce the
A
brain stem
9
Q
midbrain and cervical flexures move
A
the forebrain to the brainstem
10
Q
brain folds into
A
convolutions, increases surface area allows more neurons to occupy the space
11
Q
gray matter
A
short nonmyelinated neurons and cell bodies
12
Q
white matter
A
mostly myelinated axons w some non in fiber tracts (fatty myelin gives it its color)
13
Q
ventricles
A
continuous with one another and w central canal and spinal cord
14
Q
what are the ventricles filled with
A
cerebrospinal fluid and lined by ependymal cells (neuroliga)
15
Q
lateral ventricles
A
1 deep within each cerebral hemisphere ( large c-shapes chambers)
16
Q
LV separated by a thin membrane
A
septum pellucidum
17
Q
LV communicates with
A
3rd ventricle via interventricular foramen
18
Q
3rd and 4th ventricle connected via
A
cerebral aqueduct through midbrain
19
Q
4th ventricle
A
in hindbrain dorsal to pons superior to medulla
20
Q
4th ventricle openings
A
lateral apertures (side), median apertures (roof)
21
Q
the apertures connect ventricles to
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subarachnoid space (fluid-filled space around brain)
22
Q
spinal cord
A
central cavity surrounded gray matter outer white matter
23
Q
brain stem
A
gray matter within the white matter
24
Q
cerebrum and cerebellum
A
island of gray matter within white matter outer cortex of gray matter
25
cerebral hemisphere
superior part of the brain
26
elevated ridges of tissues
gyri
27
shallow grooves
sulci
28
deeper grooves
fissures
29
longitudinal fissure
separates the cerebral hemispheres
30
transverse cerebral fissure
separates cerebral hemispheres from cerebellum
31
central sulcus
separates frontal lobe from parietal lobe
32
bordering central sulcus
precentral gyrus (anterior) postcentral gyrus (posterior)
33
parieto-occiptal sulcus
posterior on the medial surface separates occipital from parietal lobe
34
deep lateral sulcus
outline temporal lobe separates it from parietal and frontal lobes
35
insula
deep within lateral sulcus
36
cerebral hemispheres basic regions
cerebral cortex, internal white matter, basal nuclei
37
cerebral cortex (conscious mind)
initiate voluntary movements
38
cerebral cortex contains
gray matter: neuron cell bodies, dendrites, associates glia and blood vessels
39
PET scans
maximal metabolic activities in brain
40
MRI scans
reveal blood flow
41
PET MRI
show motor and sensory functions in areas called domains
42
cerebral cortex contains
motor, sensory, association areas
43
each hemisphere concerned with the sensory and motor functions
of the contralateral side of body
44
Where is the primary motor cortex located?
In the precentral gyrus of the frontal lobe of each hemisphere
45
What type of neurons are found in the primary motor cortex that allow for the control of voluntary movements?
Pyramidal cells
46
What are the massive voluntary motor tracts that project from the primary motor cortex to the spinal cord called?
Pyramidal tracts or corticospinal tracts
47
What is the term for the spatial mapping of the body in CNS structures?
Somatotopy
48
In the primary motor cortex, where are the pyramidal cells that control foot movements located?
In one specific area, distinct from those controlling hand movements
49
How is the body represented in the primary motor cortex?
Upside down, with the head at the inferolateral part and toes at the superomedial end
50
Which body areas have disproportionately large representations in the primary motor cortex?
* Face
* Tongue
* Hands
51
What does the motor homunculus illustrate?
The disproportionate representation of body areas in the primary motor cortex
52
True or False: The left primary motor gyrus controls muscles on the left side of the body.
False
53
What is misleading about the motor homunculus representation?
It implies a one-to-one correspondence between cortical neurons and the muscles they control
54
What is the actual organization of control in the primary motor cortex?
Multiple spots on the cortex control a given muscle, and individual neurons send impulses to more than one muscle
55
Fill in the blank: The primary motor cortex map is an orderly but _______ map.
Fuzzy
56
How do neurons that control related movements interact in the primary motor cortex?
They intermingle and overlap
57
How do neurons that control unrelated movements behave in the primary motor cortex?
They do not cooperate in motor activity
58
What does the motor homunculus show about the organization of the primary motor cortex?
Broad areas are devoted to the leg, arm, torso, and head, but organization is diffuse
59
where is the premotor cortex
anterior to the precentral gyrus in frontal lobe
60
what does the premotor cortex help with
plan movement
61
What types of tasks does the premotor cortex help to sequence?
Complex tasks such as playing a musical instrument or typing
## Footnote
These tasks require coordination of multiple motor movements.
62
How does the premotor cortex use sensory information?
It uses highly processed sensory information to control voluntary actions that depend on sensory feedback
## Footnote
An example is feeling for a light switch in a dark room.
63
What role does the premotor cortex play in muscle movement?
Coordinates the movement of several muscle groups either simultaneously or sequentially
## Footnote
This coordination is essential for complex motor activities.
64
What percentage of pyramidal tract fibers does the premotor cortex supply?
About 15%
## Footnote
These fibers influence motor activity more directly.
65
What analogy is used to describe the function of the premotor cortex?
Staging area for skilled motor activities
## Footnote
This analogy emphasizes its preparatory role in motor control.
66
Where does Broca's area lie in the brain?
Anterior to the inferior region of the premotor area
67
In which hemisphere is Broca's area usually present?
Left hemisphere
68
What is the primary function of Broca's area?
Directs the muscles involved in speech production
69
True or False: Broca's area is only active during speech production.
False
70
What other activities does Broca's area become active during?
Preparing to speak and planning many voluntary motor activities
71
Fill in the blank: Broca's area has long been considered a special motor _______.
speech area
72
where is the frontal eye field located
partially and anterior to the premotor cortex and superior to broca's area
73
what does frontal eye field control
voluntary movement of the eye
74
What happens when there is damage to localized areas of the primary motor cortex?
Paralysis of the body muscles controlled by those areas
## Footnote
If the lesion is in the right hemisphere, the left side of the body will be paralyzed
75
What type of control is lost due to damage in the primary motor cortex?
Voluntary control
## Footnote
Muscles can still contract reflexively
76
What is the effect of destruction of the premotor cortex?
Loss of the motor skill(s) programmed by that region
## Footnote
Does not impair muscle strength or ability to perform discrete individual movements
77
If the premotor area controlling typing is damaged, what can you still do?
Make the same movements with your fingers
## Footnote
You cannot type with your usual speed
78
What is required to reprogram a skill into another set of premotor neurons?
Practice
## Footnote
Similar to the initial learning process
79
In which lobes are the sensory areas of the cortex located?
Parietal, insular, temporal, and occipital lobes
80
What is the function of the sensory areas of the cortex?
They are concerned with conscious awareness of sensation.
81
Where is the primary somatosensory cortex located?
In the postcentral gyrus of the parietal lobe, just behind the primary motor cortex.
82
What types of information do neurons in the primary somatosensory cortex receive?
Information from somatic sensory receptors in the skin and from proprioceptors
83
What are proprioceptors and where are they located?
Proprioceptors are receptors in skeletal muscles, joints, and tendons that inform the brain of the body’s position in space.
84
What is spatial discrimination?
The ability of the primary somatosensory cortex to identify the body region being stimulated.
85
How is the body represented in the primary somatosensory cortex?
Spatially and upside down, with the right hemisphere processing input from the left side of the body.
86
What determines the size of a region in the somatosensory cortex?
The sensitivity of the body region, which depends on the number of sensory receptors it has.
87
Which body regions are the most sensitive and occupy the largest areas in the somatosensory homunculus?
The face (especially the lips) and the fingertips.
88
Where is the somatosensory association cortex located?
Just posterior to the primary somatosensory cortex.
89
What is the main function of the somatosensory association cortex?
To integrate sensory inputs to produce an understanding of objects being felt.
90
How does the somatosensory association cortex help in object recognition?
It uses stored memories of past sensory experiences to identify objects by touch.
91
What might happen if the somatosensory association cortex is damaged?
A person may be unable to recognize objects by touch alone, needing to look at them instead.
92
Where is the primary visual cortex located?
At the extreme posterior tip of the occipital lobe, mostly buried in the calcarine sulcus.
93
What kind of information does the primary visual cortex receive?
Visual input originating from the retina of the eye.
94
How is the visual field represented in the primary visual cortex?
The opposite side of the visual space is mapped onto it, similar to the body mapping in the somatosensory cortex.
95
What surrounds the primary visual cortex and helps interpret visual information?
The visual association area.
96
What is the function of the visual association area?
To interpret visual stimuli using past experiences, enabling recognition of objects, faces, and movement
97
What part of the brain is involved in complex visual processing?
The entire posterior half of the cerebral hemispheres.
98
Where is the primary auditory cortex located?
On the superior margin of the temporal lobe, next to the lateral sulcus
99
What does the primary auditory cortex interpret?
Pitch, loudness, and location of sound.
100
What is the role of the auditory association area?
It allows perception of sounds as recognizable stimuli like speech, music, or thunder.
101
What brain area associated with language includes parts of the auditory cortex?
Wernicke’s area.
102
Where is the vestibular cortex located?
In the posterior part of the insula and adjacent parietal cortex.
103
What is the function of the vestibular cortex?
Conscious awareness of balance and the position of the head in space.
104
Where is the primary olfactory cortex located?
On the medial aspect of the temporal lobe, in the piriform lobe dominated by the uncus.
105
How does the olfactory cortex receive information?
Afferent fibers from smell receptors send impulses via the olfactory tracts to the olfactory cortices.
106
What is the function of the olfactory cortex?
It provides conscious awareness of different odors.
107
Which parts of the rhinencephalon are still devoted to smell in humans?
The olfactory bulbs, tracts, and the olfactory cortices
108
How is the rhinencephalon related to emotions?
Most of it evolved into the limbic system, linking odors with emotions and memories.
109
what is the gustatory cortex involved in
perceiving taste stimuli
110
where is the gustatory cortex found
in the insulation deep to the temporal lobe
111
where is the visceral sensory area
cortex of the insulation posterior to the gustatory cortex
112
what is the visceral sensory involved in
conscious perception of visceral sensation (upset stomach, full bladder)
113
damage in the primary visual cortex result in
functional blindness (see but not understand)
114
what is the multimodal association cortex
allows us to give meaning to the info we receive -> store in memory ->tie it to old memories ->decide what action to do
115
these actions are relayed to
the premotor cortex then it communicates with the motor cortex
116
where is the anterior association area found
in the frontal lobe called the prefrontal cortex
117
anterior association is involved in
learning abilities, recall, personality
118
where is the posterior association
its a large region has parts of temporal, parietal, and occipital lobes
119
posterior as. plays role in
recognizing patterns and faces and localizing us and in understanding written and spoken language
120
limbic association includes
cingulate gyrus, parahippocampal gyrus and hippocampus
121
limbic as. provides
emotional impact makes scenes imp to us
122
tumors in anterior ass. causes
mental and personality disorders (loss of judgment and inhibtions)
123
lesions in the posterior ass. causes
awareness of self space (refuse to wash or dress opp side of body thinking its not theirs)
124
What is meant by cerebral lateralization?
It refers to the division of labor between the two cerebral hemispheres, where each has specialized functions.
125
What is cerebral dominance?
It designates the hemisphere that is dominant for language—typically the left hemisphere in most people.
126
In what percentage of people is the left hemisphere dominant for language, math, and logic?
About 90% of people.
127
What kinds of abilities are typically associated with the right hemisphere?
Visual-spatial skills, intuition, emotion, artistic and musical abilities, and creativity.
128
What tasks is the dominant (usually left) hemisphere responsible for?
Language abilities, mathematical calculations, and logical reasoning.
129
Q: What is the relationship between cerebral dominance and handedness?
Most left-dominant individuals are right-handed; right-dominant individuals tend to be left-handed.
130
What is ambidexterity and how is it related to brain dominance?
Ambidexterity is the ability to use both hands equally well, often seen in individuals whose cerebral functions are shared between hemispheres.
131
How do the two hemispheres communicate with each other?
Through connecting fiber tracts, allowing nearly instantaneous communication and full functional integration.
132
Is one cerebral hemisphere better at everything than the other?
No, each hemisphere is better at specific functions, but neither is superior overall.
133
What is the function of the cerebral white matter?
It facilitates communication between different cerebral areas and between the cerebral cortex and lower CNS centers.
134
What is white matter composed of?
Mostly myelinated nerve fibers bundled into large tracts.
135
What are the three classifications of white matter fibers based on their direction?
Association fibers, commissural fibers, and projection fibers.
136
What do association fibers connect?
Different parts of the same cerebral hemisphere.
137
What is the difference between short and long association fibers?
Short fibers connect adjacent gyri; long fibers connect different cortical lobes.
138
What do commissural fibers connect?
Corresponding gray areas of the two cerebral hemispheres.
139
What is the largest commissural fiber?
The corpus callosum.
140
What is the function of commissural fibers?
They allow the two hemispheres to function as a coordinated whole.
141
What do projection fibers do?
They connect the cerebral cortex with lower brain or spinal cord centers, transmitting sensory input and motor output
142
How do projection fibers run compared to association and commissural fibers?
Projection fibers run vertically, while association and commissural fibers run horizontally.
143
What is the internal capsule?
A compact band of projection fibers that passes between the thalamus and basal nuclei.
144
What is the corona radiata?
The fanlike arrangement of projection fibers superior to the internal capsule, spreading into the cerebral cortex.
145
What is the primary function of the basal nuclei?
Control of movement.
146
What are the main components of the basal nuclei in each hemisphere?
Caudate nucleus, putamen, and globus pallidus
147
What two structures form the striatum?
The caudate nucleus and the putamen.
148
What two structures form the lentiform nucleus?
The putamen and the globus pallidus.
149
Are the putamen and globus pallidus functionally the same?
No, they are functionally separate despite forming a physical mass
150
With which structures are the basal nuclei functionally associated?
The subthalamic nuclei and the substantia nigra.
151
What kind of input do the basal nuclei receive?
Input from the entire cerebral cortex, other subcortical nuclei, and each other.
152
Where do the basal nuclei project their output?
To the premotor and prefrontal cortices via the thalamus.
153
Do the basal nuclei have direct access to motor pathways?
No, they influence movement indirectly.
154
What motor roles do the basal nuclei play?
They help start, stop, and regulate the intensity of slow or stereotyped movements, and inhibit unnecessary or antagonistic movements.
155
Besides motor functions, what other roles do the basal nuclei play?
They are involved in cognition and emotion, filtering out inappropriate responses.
156
What are two major disorders associated with basal nuclei dysfunction?
Huntington’s disease and Parkinson’s disease.
157
What are the three main paired structures of the diencephalon?
thalamus, hypothalamus, and epithalamus.
158
What ventricle is enclosed by the diencephalon?
The third ventricle.
159
What is the thalamus and where is it located?
It is a bilateral, egg-shaped structure forming the superolateral walls of the third ventricle; it makes up 80% of the diencephalon.
160
What connects the two thalamic nuclei in most people?
The interthalamic adhesion (intermediate mass).
161
What is the main function of the thalamus?
It serves as the relay station for information going to the cerebral cortex
162
What types of input converge in the thalamus?
Afferent impulses from all senses and all parts of the body.
163
What do the ventral posterolateral nuclei of the thalamus do?
They receive sensory impulses such as touch, pressure, and pain.
164
What are the roles of the lateral and medial geniculate bodies?
They are relay centers for visual and auditory information, respectively.
165
What kind of sensory processing occurs in the thalamus?
Crude recognition of sensation as pleasant or unpleasant; precise localization happens in the cerebral cortex.
166
Besides sensory input, what other kinds of input are processed by the thalamus?
Emotional and visceral function (from the hypothalamus), motor instructions (from cerebellum and basal nuclei), and memory/sensory integration.
167
Which thalamic nuclei help regulate emotion and visceral function?
The anterior nuclei.
168
Which nuclei relay motor signals to the cortex?
The ventral lateral and ventral anterior nuclei.
169
Which nuclei are involved in memory or sensory integration?
The pulvinar, lateral dorsal, and lateral posterior nuclei.
170
What are the major roles of the thalamus?
Mediating sensation, motor activities, cortical arousal, learning, and memory.
171
Where is the hypothalamus located?
Below the thalamus, forming the inferolateral walls of the third ventricle and capping the brain stem.
172
Q: What are the mammillary bodies and their function?
Paired nuclei in the hypothalamus that act as relay stations in the olfactory pathways.
173
What is the infundibulum?
A stalk of hypothalamic tissue connecting the pituitary gland to the hypothalamus.
174
What is the main function of the hypothalamus?
It is the main visceral control center, playing a major role in maintaining homeostasis.
175
How does the hypothalamus control the autonomic nervous system (ANS)?
It influences activities like blood pressure, heart rate, digestion, and pupil size by acting through brain stem and spinal cord centers.
176
What is the hypothalamus's role in emotions?
It is part of the limbic system and initiates physical responses to emotions like fear, rage, and pleasure.
177
How does the hypothalamus regulate body temperature?
Through hypothalamic neurons that monitor temperature and initiate sweating or shivering.
178
How does the hypothalamus regulate food intake?
It responds to nutrient and hormone levels to trigger feelings of hunger or satiety.
179
What is the role of hypothalamic osmoreceptors?
They detect high solute concentration in body fluids and trigger ADH release and thirst to maintain water balance.
180
How does the hypothalamus regulate sleep-wake cycles?
Via the suprachiasmatic nucleus, which acts as the biological clock responding to light-dark signals.
181
How does the hypothalamus control the endocrine system?
It regulates the anterior pituitary via releasing/inhibiting hormones and produces ADH and oxytocin in the supraoptic and paraventricular nuclei.
182
Where is the midbrain located?
Between the diencephalon and the pons.
183
What are the cerebral peduncles?
Ventral midbrain structures that contain descending corticospinal motor tracts.
184
What structure connects the third and fourth ventricles through the midbrain?
The cerebral aqueduct.
185
What is the function of the periaqueductal gray matter?
It suppresses pain and connects fear-processing regions (like the amygdala) with autonomic "fight-or-flight" responses.
186
What cranial nerves have nuclei in the midbrain?
Oculomotor (III) and Trochlear (IV) nerves
187
What is the corpora quadrigemina?
The largest midbrain nuclei, made up of the superior and inferior colliculi.
188
What is the function of the superior colliculi?
They are visual reflex centers that coordinate head and eye movement in response to visual stimuli.
189
What is the function of the inferior colliculi?
They relay auditory information and mediate reflexive responses to sound
190
What is the substantia nigra and its role?
A darkly pigmented nucleus that releases dopamine and is linked to the basal nuclei. Its degeneration causes Parkinson’s disease.
191
What is the red nucleus and its function?
A reddish structure involved in motor pathways related to limb flexion; part of the reticular formation.
192
Where is the pons located?
Between the midbrain and the medulla oblongata; separated from the cerebellum dorsally by the fourth ventricle.
193
What does "pons" mean and what is its main function?
"Pons" means "bridge"; it serves mainly as a conduction pathway for signals between higher brain centers and the spinal cord, and between the motor cortex and cerebellum.
194
What are the two main types of fibers in the pons and their orientation?
Projection fibers: run longitudinally.
Transverse fibers: run horizontally and dorsally, forming the middle cerebellar peduncles.
195
What is the role of the middle cerebellar peduncles?
They connect the pons to the cerebellum and relay motor information from the cortex.
196
Which cranial nerves originate from the pons?
Trigeminal (V), Abducens (VI), and Facial (VII) nerves.
197
What do pontine nuclei contribute to besides motor relay?
Some are part of the reticular formation and help the medulla regulate breathing rhythm.
198
Where is the medulla oblongata located?
It is the lowest part of the brainstem, blending into the spinal cord at the foramen magnum.
199
What forms the ventral wall of the fourth ventricle?
The medulla and pons.
200
What forms the dorsal wall of the fourth ventricle?
A thin, capillary-rich membrane called the choroid plexus, next to the cerebellum.
201
What is the primary role of the medulla oblongata in the body?
It acts as an autonomic reflex center involved in maintaining homeostasis.
202
What are the two main parts of the cardiovascular center in the medulla?
Cardiac center: adjusts force and rate of heart contractions.
Vasomotor center: regulates blood vessel diameter to control blood pressure.
203
Q: What is the function of the respiratory centers in the medulla?
They generate respiratory rhythm and work with pontine centers to control the rate and depth of breathing.
204
Name at least three other functions regulated by centers in the medulla.
Vomiting, hiccuping, swallowing, coughing, and sneezing.
205
Why do the hypothalamus and medulla have overlapping functions?
Because the hypothalamus relays its instructions through medullary reticular centers to control many visceral functions.
206
What percentage of the brain's total mass does the cerebellum account for?
11%
207
Where is the cerebellum located relative to the pons and medulla?
It is located dorsal to the pons and medulla.
208
What separates the cerebellum from the occipital lobes of the cerebrum?
The transverse cerebral fissure.
209
What is the primary function of the cerebellum?
It ensures precise timing and patterns of skeletal muscle contraction for smooth, coordinated movements
210
Is cerebellar activity conscious or subconscious?
Subconscious—we are not aware of it
211
What structure connects the two cerebellar hemispheres?
The vermis.
212
What are the pleat-like folds of the cerebellar surface called?
Folia.
213
Name the three lobes of the cerebellum.
Anterior, posterior, and flocculonodular lobes.
214
What is the "tree of life" in the cerebellum, and what does it represent?
The arbor vitae, which is the pattern of internal white matter.
215
What are the only cerebellar cortical neurons that send axons to the central nuclei?
Purkinje cells.
216
What part of the cerebellum influences trunk and girdle muscles?
The medial portions
217
What do the intermediate parts of the cerebellar hemispheres control?
Distal limb movements and skilled actions.
218
What is the role of the lateralmost parts of the cerebellar hemispheres?
Planning movements by integrating information from cerebral association areas.
219
What cerebellar region adjusts posture and maintains balance?
The flocculonodular lobes, which receive input from the inner ear's equilibrium apparatus.
220
What are the three paired fiber tracts that connect the cerebellum to the brain stem?
The superior, middle, and inferior cerebellar peduncles.
221
Do fibers entering and leaving the cerebellum cross to the opposite side or remain on the same side?
They are mostly ipsilateral (same side).
222
What is the function of the superior cerebellar peduncles?
They carry instructions from the deep cerebellar nuclei to the cerebral motor cortex via thalamic relays.
223
Does the cerebellum have direct connections with the cerebral cortex?
No, like the basal nuclei, it has no direct connections
224
What information do the middle cerebellar peduncles carry?
They carry one-way communication from the pons, informing the cerebellum of voluntary motor activities initiated by the motor cortex.
225
What do the inferior cerebellar peduncles convey?
They bring sensory information from muscle proprioceptors and vestibular nuclei related to equilibrium.
226
What is the first step in cerebellar processing?
The cerebral motor areas notify the cerebellum of their intent to initiate voluntary movement.
227
What type of sensory information does the cerebellum receive during movement planning?
From proprioceptors, visual, and equilibrium pathways.
228
What does the cerebellar cortex do with the information it receives?
It calculates the best way to coordinate muscle force, direction, and extent for smooth movement.
229
How does the cerebellum send its movement coordination “blueprint”?
Through the superior peduncles to the motor cortex and brain stem nuclei.
230
What happens when the cerebellum is damaged?
It causes loss of muscle tone and clumsy, uncertain movements.
231
Besides motor control, what other functions is the cerebellum thought to be involved in?
Thinking, language, and emotion
232
What do imaging studies and observations of cerebellar injury suggest about the cerebellum?
That it may have nonmotor roles in cognition and emotion.
233
How might the cerebellum function in cognitive and emotional systems?
By comparing actual output with expected output and making adjustments—similar to its role in motor control.
234
Is the cerebellum’s role in nonmotor functions fully understood?
No, much still remains to be discovered
235
What are the two key brain areas involved in language?
Broca’s area and Wernicke’s area.
236
What happens when Broca’s area is damaged?
The person can understand language but has difficulty speaking.
237
What happens when Wernicke’s area is damaged?
The person can speak fluently but the speech is nonsensical (“word salad”) and they have difficulty understanding language.
238
What brain structures form the "language implementation system"?
Broca’s area, Wernicke’s area, and the basal nuclei.
239
What role do the right hemisphere counterparts of Broca’s and Wernicke’s areas play?
They handle nonverbal emotional aspects of language, like tone, gestures, and emotional content.
240
What are the four types of memory?
Declarative (facts), procedural (skills), motor, and emotional memory
241
What is short-term memory (STM)?
A temporary working memory, limited to about 7–8 chunks of information
242
What is long-term memory (LTM)?
A limitless capacity memory store where information can be retained permanently
243
What factors aid the transfer of STM to LTM?
Emotional state, rehearsal, association, and automatic memory.
244
What neurotransmitter is released during emotionally charged events and helps memory?
Norepinephrine.
245
What is memory consolidation?
The process of fitting new information into existing categories in the brain, mainly involving the hippocampus and temporal lobes.
246
What is anterograde amnesia?
The inability to form new memories after brain damage
247
What is retrograde amnesia?
The loss of past memories formed before the brain injury.
248
Where are specific types of memories stored?
Visual memories in the occipital cortex, music in the temporal cortex
249
What four elements protect the brain?
Bone (skull), meninges, cerebrospinal fluid (CSF), and the blood-brain barrier.
250
What are the meninges?
three connective tissue membranes that lie external to the CNS organs
251
What are the functions of the meninges?
Cover and protect the CNS
Protect blood vessels and enclose venous sinuses
Contain cerebrospinal fluid
Form partitions in the skull
252
Name the meninges from outermost to innermost
Dura mater, arachnoid mater, pia mater.
253
What does "dura mater" mean?
Tough mother" – it's the strongest meninx.
254
What are the two layers of the cranial dura mater?
Periosteal layer (attached to skull)
Meningeal layer (true outer covering of brain)
255
Where do the two layers of the dura mater separate?
At dural venous sinuses, which drain blood from the brain into the internal jugular veins.
256
What is the purpose of dural septa?
To limit brain movement within the skull by forming internal partitions.
257
What is the falx cerebri?
A sickle-shaped fold of dura mater that dips into the longitudinal fissure between the cerebral hemispheres.
258
Where does the falx cerebri attach anteriorly?
To the crista galli of the ethmoid bone.
259
What is the falx cerebelli?
A midline partition that runs along the vermis of the cerebellum
260
What is the tentorium cerebelli?
A tent-like horizontal fold of dura mater that separates and supports the cerebrum from the cerebellum.
261
What does "arachnoid mater" mean?
"Spider mother" — named for its web-like appearance.
262
Where is the arachnoid mater located?
Between the dura mater and pia mater.
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What space lies beneath the arachnoid mater?
The subarachnoid space.
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What does the subarachnoid space contain?
Cerebrospinal fluid (CSF) and largest blood vessels serving the brain.
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What structures help absorb CSF into venous blood?
Arachnoid granulations (villi) — they protrude into the superior sagittal sinus.
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What does "pia mater" mean?
"Gentle mother" — the delicate, innermost meninx.
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How is the pia mater unique in its placement?
It clings tightly to the brain like plastic wrap, following every gyrus and sulcus.
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What type of tissue is the pia mater composed of?
Delicate connective tissue rich with tiny blood vessels that nourish the brain.
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What kind of brain covering does the arachnoid mater form?
A loose covering that does not dip into sulci.
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What lies between the dura mater and arachnoid mater?
The subdural space, containing a film of fluid.
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What is the subarachnoid space?
A wide space beneath the arachnoid, filled with CSF and large blood vessels.
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What structures anchor the arachnoid mater to the pia mater?
Spiderweb-like extensions (like a spider's web).
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What are arachnoid granulations?
Projections that absorb CSF into the superior sagittal sinus.
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What is the pia mater composed of?
Delicate connective tissue with many tiny blood vessels.
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How does the pia mater interact with brain tissue?
It clings tightly to the brain, following every gyrus and sulcus.
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What happens to pia mater as blood vessels enter the brain?
It follows the arteries into the brain tissue briefly.
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What are the functions of CSF?
CSF protects, nourishes, and reduces brain weight by ~97%. It may also carry chemical signals.
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What forms CSF?
Choroid plexuses in each ventricle, made of capillaries, pia mater, and ependymal cells.
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How do ependymal cells help regulate CSF composition?
They use ion pumps to control filtrate content and maintain ion balance
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How often is CSF replaced?
Every 8 hours; about 500 ml is produced daily.
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How does CSF circulate?
Through ventricles, exits via lateral and median apertures, flows through subarachnoid space, and reabsorbed by arachnoid granulations.
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What is meningitis?
Inflammation of the meninges, often due to bacterial or viral infection.
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How is meningitis diagnosed?
By lumbar puncture to examine CSF for signs of infection
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what is hydrocephalus?
Build-up of CSF in the ventricles due to impaired drainage, increasing brain pressure.
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What causes hydrocephalus?
Blockage by clots, tumors, trauma, or meningitis.
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How is hydrocephalus treated?
By inserting a shunt to drain excess CSF into the abdomen or bloodstream.
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What is the main function of the blood-brain barrier?
To maintain a stable internal environment in the brain, protecting neurons from harmful or fluctuating substances in the blood.
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Why is the brain more sensitive to chemical fluctuations than other tissues?
What are the structural components of the BBB?
A:
Tight junctions between capillary endothelial cells
Astrocyte end-feet
Pericytes
Basement membrane
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What is the role of astrocytes and pericytes in the BBB?
They help maintain and regulate the endothelial cells and signal the formation of tight junctions.
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How do lipid-soluble substances pass through the BBB?
By simple diffusion through the plasma membrane.
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What are some lipid-soluble substances that easily cross the BBB?
Oxygen, carbon dioxide, fatty acids, alcohol, nicotine, and anesthetics.
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How are essential nutrients like glucose and amino acids transported across the BBB?
By facilitated diffusion via specific transport proteins.
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How are larger molecules moved across the BBB?
By transcytosis.
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What types of substances are blocked by the BBB?
Metabolic wastes, proteins, toxins, most drugs, and nonessential amino acids.
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How does the BBB handle potassium ions and small amino acids?
They are actively pumped out of the brain.
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What is the role of the basement membrane in the BBB?
It contains enzymes that destroy certain chemicals (e.g., epinephrine, norepinephrine) that could overstimulate neurons.
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Is the blood-brain barrier uniform throughout the brain?
No — some regions lack a BBB entirely, especially around the third and fourth ventricles.
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Name a brain area where the BBB is absent and why.
The vomiting center in the brainstem — it must monitor blood for toxins.
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Why is the hypothalamus an exception to the BBB?
It needs to sample blood to regulate water balance, temperature, and metabolism.
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Why are newborns more vulnerable to CNS damage from bloodborne substances?
Because their BBB is not fully developed.
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What can cause localized breakdown of the BBB?
Brain injuries, which may disrupt endothelial cell function or tight junctions.
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What regions report the highest burden of head injury?
Southeast Asia and the Western Pacific.
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What causes brain damage in a car crash?
Both direct impact and the rebound (coup-contrecoup) injury as the brain hits the opposite side of the skull.
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What are the two main classifications of TBI?
Focal (specific area) and Diffuse (widespread).
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Examples of focal brain injuries?
contusions and hematomas.
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Examples of diffuse brain injuries?
Concussions and diffuse axonal injuries.
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What is a concussion?
Temporary alteration in brain function due to a blow to the head.
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What are the risks of repeated concussions?
Cumulative neurological damage.
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What is a contusion?
A bruising of the brain, possibly causing permanent damage.
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What happens with brainstem contusions?
they always cause coma, possibly permanent, due to reticular activating system damage
311
What is a diffuse axonal injury?
Widespread stretching/tearing of axons, especially near the brainstem
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Outcomes of severe diffuse axonal injury?
High mortality or persistent vegetative state.
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What signs suggest intracranial hemorrhage after head trauma?
Initial lucidity followed by neurological deterioration.
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Consequences of increased intracranial pressure (ICP)?
Brainstem herniation through the foramen magnum → loss of vital functions.
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reatment for hematomas?
Surgical removal and repair of vessels.
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What is cerebral edema?
Swelling of the brain due to increased fluid content.
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Causes of cerebral edema?
Trauma, infection, tumors, or hypoxia.
318
How does cerebral edema increase ICP?
Leaky capillaries let plasma proteins in, drawing water into the brain.
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Drug used to treat cerebral edema?
Osmitrol (mannitol) — draws water into the vasculature.
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Side effects of Osmitrol?
Risk of dehydration and electrolyte imbalances.
321
Most common nervous system disorder?
Stroke (CVA) — also the 3rd leading cause of death in North America.
322
What causes a CVA?
Blocked or burst cerebral blood vessel, leading to ischemia and cell death.
323
Most common cause of stroke?
Blood clot blocking a cerebral artery (thrombotic or embolic stroke).
324
What is a transient ischemic attack (TIA)?
A temporary mini-stroke (5–50 mins) with reversible symptoms — a warning sign of a full stroke.
325
Effects of stroke?
Hemiplegia, sensory loss, speech issues, cognitive deficits
326
Main excitotoxic agent after stroke?
Glutamate — overexcites neurons to death.
327
Most effective stroke treatment?
tPA (tissue plasminogen activator) — dissolves clots if given early
328
Mechanical alternative to tPA?
Clot retrieval devices (e.g., corkscrew-type tools).
329
What is Alzheimer’s disease?
A progressive neurodegenerative disease leading to dementia.
330
Early signs of Alzheimer’s?
Memory loss, disorientation, shortened attention, language difficulties.
331
Pathological features of AD?
Beta-amyloid plaques (extracellular)
Neurofibrillary tangles (intracellular tau)
332
What is APP?
Amyloid precursor protein — its cleavage produces beta-amyloid.
333
What is tau protein's role in neurons?
Stabilizes microtubules; in AD, it misfolds and forms tangles.
334
Which brain regions are most affected in AD?
Hippocampus, basal forebrain, cortical association areas.
335
What causes brain shrinkage in AD?
Neuron death due to misfolded protein accumulation.
336
What percentage of people over 65 are affected by AD?
5–15%; up to 50% over 85.
337
Which neurotransmitter is particularly affected in Alzheimer’s disease?
Acetylcholine.
338
What happens to acetylcholine levels in Alzheimer's disease?
There is a shortage due to the loss of acetylcholine-using neurons.
339
How do drugs that inhibit acetylcholine breakdown help AD patients?
hey slightly enhance cognitive function.
340
What causes Parkinson’s disease?
Degeneration of dopamine-releasing neurons in the substantia nigra.
341
What are the characteristic symptoms of Parkinson’s disease?
Resting tremor ("pill-rolling"), forward-bent posture, shuffling gait, stiff facial expression, and slowness in initiating/executing movement.
342
Why do symptoms of PD occur?
Because dopamine-deprived basal nuclei become overactive.
343
What is the role of l-dopa in Parkinson’s treatment?
it crosses the blood-brain barrier and is converted to dopamine.
344
Why does l-dopa become ineffective over time?
Because more dopamine-releasing neurons die off.
345
How can the effectiveness of l-dopa be prolonged?
By combining it with drugs that inhibit dopamine breakdown.
346
What advanced treatment can help PD patients who no longer respond to drugs?
Deep brain stimulation via implanted electrodes.
347
What is a potential future gene therapy for PD?
Inserting genes to make brain cells secrete GABA, which inhibits abnormal activity.
348
What is the status of stem cell therapy for PD?
It’s promising, but current results are not better than conventional treatments.
349
What causes Huntington’s disease?
A hereditary mutation leading to accumulation of mutant huntingtin protein.
350
What brain structures are primarily affected in HD?
Basal nuclei and later the cerebral cortex.
351
What are early symptoms of Huntington’s disease?
Wild, jerky, almost continuous movements called chorea.
352
Is Huntington’s disease progressive or static?
Progressive.
353
What happens in the late stages of Huntington’s disease?
Marked mental deterioration.
354
How is Huntington’s disease treated?
With drugs that block dopamine’s effects.
355
What does the knee-jerk reflex test assess?
Basic spinal cord and upper brain center function.
356
What could abnormal reflex responses indicate?
Serious CNS disorders like intracranial hemorrhage, MS, or hydrocephalus.
357
What imaging techniques help diagnose CNS dysfunction?
CT, MRI, PET scans.
358
What can PET scans localize?
Seizure-generating brain lesions (epileptic tissue).
359
What can radiotracer dyes detect in Alzheimer’s patients?
Beta-amyloid plaques for earlier diagnosis.
360
Where does the spinal cord begin and end in the body?
It extends from the foramen magnum to the level of the first or second lumbar vertebra (L1–L2).
361
What is the approximate length and thickness of the spinal cord?
About 42 cm long and 1.8 cm thick.
362
What are the two primary functions of the spinal cord?
It serves as a two-way conduction pathway to and from the brain and is a major reflex center.
363
What protects the spinal cord?
Bone, meninges, and cerebrospinal fluid (CSF).
364
What space lies between the spinal dura mater and vertebrae, and what does it contain?
The epidural space, which contains fat and a network of veins.
365
What fills the subarachnoid space of the spinal cord?
Cerebrospinal fluid (CSF).
366
Why is the subarachnoid space below L3 a safe site for a lumbar puncture?
The spinal cord ends around L1–L2, so there’s no risk of damaging it when inserting a needle below L3.
367
What is the conus medullaris?
The cone-shaped terminal end of the spinal cord.
368
What is the filum terminale and what is its function?
A fibrous extension of the conus medullaris that anchors the spinal cord to the coccyx.
369
What are denticulate ligaments and what do they do?
Saw-toothed extensions of pia mater that secure the spinal cord to the dura mater.
370
What are the cervical and lumbar enlargements?
Regions of the spinal cord where nerves serving the limbs arise.
371
How many pairs of spinal nerves are there in humans?
31 pairs.
372
What is the cauda equina?
A collection of spinal nerve roots at the inferior end of the vertebral canal resembling a horse’s tail.
373
Why does the cauda equina exist?
because the vertebral column grows faster than the spinal cord during development.
374
What two grooves divide the spinal cord into left and right halves?
The ventral (anterior) median fissure and the dorsal (posterior) median sulcus.
375
Where is gray matter located in the spinal cord?
In the central core.
376
Where is white matter located in the spinal cord?
On the outer portion surrounding the gray matter.
377
What runs through the center of the spinal cord?
The cerebrospinal fluid–filled central canal.
378
What shape does the gray matter form in a cross section of the spinal cord?
It resembles the letter H or a butterfly.
379
What connects the lateral gray masses across the spinal cord?
The gray commissure.
380
What are the dorsal horns of the spinal cord?
The posterior projections of gray matter.
381
What additional gray matter structure is found in thoracic and superior lumbar regions?
The lateral horns.
382
What are the ventral horns of the spinal cord?
The anterior projections of gray matter.
383
What type of neurons are found in the spinal cord gray matter?
All are multipolar neurons.
384
What types of neurons are found in the dorsal horns?
interneurons only.
385
What types of neurons are found in the ventral horns?
Mainly somatic motor neurons, with some interneurons.
386
Where do the axons of somatic motor neurons exit the spinal cord?
Through ventral rootlets that merge into ventral roots.
387
Why are the ventral horns enlarged in cervical and lumbar regions?
Because they innervate the limbs and thus have more motor neurons.
388
What is found in the lateral horns of the spinal cord?
Cell bodies of autonomic (sympathetic) motor neurons.
389
Do ventral roots carry sensory, motor, or both types of fibers?
motor fibers only—both somatic and autonomic.
390
What forms the dorsal root of a spinal nerve?
Afferent (sensory) fibers from peripheral sensory receptors.
391
Where are the cell bodies of sensory neurons located?
in the dorsal root ganglion (spinal ganglion).
392
What happens to sensory neurons after entering the spinal cord?
They either ascend in the white matter or synapse with interneurons in the dorsal horn.
393
What do dorsal and ventral roots fuse to form?
A spinal nerve.
394
What are the four functional zones of spinal gray matter?
Somatic sensory (SS), visceral sensory (VS), visceral motor (VM), and somatic motor (SM).
395
What is the main composition of spinal white matter?
Myelinated and unmyelinated nerve fibers.
396
What are the three directions in which white matter fibers run?
Ascending (sensory), descending (motor), and transverse (commissural).
397
What are the three columns (funiculi) of white matter?
Dorsal, lateral, and ventral funiculi.
398
What is a spinal tract?
A bundle of axons within a funiculus with a common origin and destination.
399
What results from damage to dorsal roots or sensory tracts?
Loss of sensation or paresthesias (abnormal sensations).
400
What results from damage to ventral roots or ventral horn cells?
Paralysis (loss of motor function).
401
What is flaccid paralysis?
Occurs when motor neurons are damaged; muscles cannot contract and atrophy.
402
what is spastic paralysis?
Occurs when upper motor neurons are damaged; muscles contract involuntarily and irregularly.
403
What is the result of spinal cord transection between T1 and L1?
Paraplegia—paralysis of both lower limbs.
404
What is the result of spinal cord transection in the cervical region?
Quadriplegia—paralysis of all four limbs.
405
What does hemiplegia usually indicate?
Brain injury, not spinal cord injury.
406
What is spinal shock?
Temporary loss of function below the injury site; can resolve within hours or lead to permanent damage if it persists >48 hours.
407
What is poliomyelitis?
A viral infection that destroys ventral horn motor neurons.
408
How is poliomyelitis transmitted?
Usually through feces-contaminated water.
409
What are the long-term effects of polio?
Muscle paralysis, atrophy, and potentially respiratory failure.
410
What is postpolio syndrome?
Late-onset muscle weakness and pain in polio survivors due to neuron loss.
411
What is ALS (Amyotrophic Lateral Sclerosis)?
A progressive condition destroying motor neurons and pyramidal tract fibers.
412
What are symptoms of ALS?
Loss of ability to speak, swallow, breathe; eventual death.
413
What causes ALS?
Genetic and environmental factors, possibly involving RNA processing gene mutations and glutamate excitotoxicity.
414
Are there treatments for ALS?
Two drugs are used—one reduces glutamate signaling; the other scavenges free radicals
