Chapter 13: The Brain Flashcards
1
Q
the typical brain has a volume of
A
1200 mL
2
Q
the average male brain IS __ % larger than the female brain
A
10
3
Q
the brain is visible by the __ week of development
A
4th
4
Q
what are the four major brain regions?
A
- cerebrum
- cerebellum
- diencephalon
- brainstem
5
Q
the left and right side of the brain are divided into
A
cerebral hemispheres
6
Q
the left and right hemispheres are divided by
A
deep fissures
7
Q
the surface of the cerebrum has folds called ___ and grooves called __. Function?
A
gyri; sulci; increase surface area
8
Q
the cerebral cortex has a superficial layer of
A
gray matter
9
Q
what are the 3 major functions of the cerebral cortex?
A
- conscious thought
- memory storage and processing
- sensory processing
- control of skeletal muscles
10
Q
the cerebellum is partially hidden by the
A
cerebral hemispheres
11
Q
what is the second largest brain structure?
A
cerebellum
12
Q
the cerebellum makes up __% of the brain’s volume and houses __% of its neurons
A
10% and 50%
13
Q
what is the main function of the cerebellum?
A
coordinate motor commands from the cerebral cortex
14
Q
the dienchephalon is made of two parts:
A
the thalamus and the hypothalamus
15
Q
role of the thalamus
A
sensory relay and processing
16
Q
role of the hypothalamus
A
emotions, autonomic function, hormone production
17
Q
the brainstem is made of three parts:
A
midbrain, pons, medulla oblongata
18
Q
the midbrain controls nuclei that : (3)
A
- process visual / auditory information
- control reflexes triggered by them
- helps maintain consciousness
19
Q
the pons connects the __ to the __
A
cerebellum; brainstem
20
Q
function of the pons (2)
A
- tracts and relay centers
2. somatic and visceral motor control
21
Q
function of medulla oblongata (2)
A
- relays sensory information through brainstem and to the thalamus
- regulates many autonomic functions
22
Q
what are ventricles?
A
chambers formed during development
23
Q
ventricles are filled with __ and lined with __
A
CSF; ependymal cells
24
Q
lateral ventricles
A
one in each cerebral hemisphere
25
interventricular foramen
connect lateral ventricles to third ventricle
26
third ventricle
located in the dienchephalon
27
cerebral aqueduct
slender canal in midbrain that connects third to fourth ventricle
28
fourth ventricle
upper part of medulla oblongata that narrow to become the central canal of the spinal cord
29
corpus callosum
thick tract of white matter that interconnects the cerebral hemispheres
30
what 4 things protect the brain?
1. cranial bones
2. cerebrospinal fluid
3. blood brain barrier
4. cranial meninges
31
the cranial meninges are continuous with the __
spinal meninges
32
3 layers of cranial meninges?
1. dura
2. arachnoid mater
3. pia matter
33
2 layers of dura mater
1. periosteal layer(outer)
| 2. meningeal layer
34
arachnoid mater consists of (3)
arachnoid membrane, arachnoid trabeculae and subarachnoid space
35
which arachnoid mater is closest to the dura mater?
arachnoid membrane
36
arachnoid trabeculae
fibrous strands through subarachnoid space; connects to the pia mater
37
subarachnoid space
between arachnoid membrane and pia mater
38
pia mater is bound to the brain by __
astrocyte processes that extend into evry fold
39
astrocyte processes are accompanied by branches of __ as they penetrate the __ of the brain
cerebral blood vessels; surface
40
what are the 3 functions of the CSF?
1. support weight of brain
2. cushion brain / spinal cord from physical trauma
3. transport nutrients, chemical messengers, wastes
41
CSF is produced and maintained by the
choroid plexus
42
what makes up the choroid plexus?
ependymal cells with tight junctions and capillaries
43
there is a choroid plexus in each __
ventricle
44
materials diffuse between CSF and __ of CNS
interstitial fluid
45
CSF circulates from __ through ___ to __
choroid plexus; ventricles; central canal of spinal cord
46
CSF is absorbed into venous circulation at
arachnoid granulations
47
what are arachnoid granulations?
fingerlike extensions of arachnoid membrane that penetrate meningeal layer of dura mater
48
all communication between brain and spinal cord travels in ascending and descending tracts through
medulla oblongata
49
the medulla oblongata coordinates __ and __
complex autonomic reflexes and visceral functions
50
the medulla oblongata contains __ centers for vital functions
autonomic
51
the medulla oblongata contains __ along sensory and motor pathways
relay stations
52
the medulla oblongata contains __ associated with 5 cranial nerves
nuclei
53
the medulla oblongata contains __ that contain tracts of motor fibers from cerebral cortex
pyramids
54
some pyramid fibers cross to opposite side of medulla, this is called
decussation
55
the pons links the cerebellum with the
midbrain, dienchephalon, cerebrum, medulla oblongata, spinal cord
56
what are the 4 groups of structures in the pons?
1. ascending, descending, transverse tracts
2. nuclei controlling respiration
3. sensory and motor nuclei of cranial nerves
4. nuclei/tracts that process/relay information sent to/from cerebellum
57
the reticular formation contains __ regulating __ and spans from __ to __
nuclei/centres; vital autonomic functions; medulla oblongata to midbrain
58
the cerebellum is the automatic ___
processing centre
59
the cerebellum monitors __ sensations (5)
proprioceptive, visual, tactile, balance, auditory
60
the cerebellum has 2 primary functions
1. adjusting postural muscles by modifying activities of brainstem centers
2. programming / fine-tuning movements controlled at conscious / subconscious levels
- refines leraned movements
- compares motor commands with proprioceptive information, makes adjustments as needed
61
what is the most complex / integrative part of the brainstem?
midbrain
62
the midbrain can direct complex motor patterns at __ level
subconscious
63
__ influences level of activity in entire nervous system
midbrain
64
what is the corpora quadrigemina?
two pairs of sensory nuclei
65
what are the two pairs of sensory nuclei in the corpora quadrigemina?
1. superior colliculus
| 2. inferior colliculus
66
the superior colliculus receives __ input from medulla oblongata and pons
visual
67
the superior colliculus controls reflex movements of the __, __ and __ in response to __ stimuli
eyes, head and neck; visual
68
the inferior colliculus receives __ input from medulla oblongata and pons
auditory
69
the inferior colliculus controls reflex movements of __, __ and __ in response to __ stimulus
head, neck and trunk; auditory
70
reticular activating system (RAS) is a specialized part of the __
reticular formation
71
function of RAS
stimulation increases alertness and attentiveness
72
damage to the RAS causes
unconsciousness
73
the red nucleus receives information from the __ and __
cerebrum and cerebellum
74
the red nucleus sends __ motor commands for __ position and __
subconscious; upper limb; muscle tone
75
what are the 3 parts of the diencephalon?
1. epithalamus
2. thalamus
3. hypothalamus
76
the epithalamus is contains the
pineal gland
77
the pineal gland is an __ structure and secretes __
endocrine; melatonin
78
the pineal gland is located in the
posterior epithalamus
79
melatonin regulates
day-night cycles and reproductive functions
80
the thalamus __ sensory information, Passing on __
filters; only a small portion
81
the final relay for ascending sensory information is projected to __ from thalamus
cerebral cortex
82
each thalamic region is connected to specific areas in the
cortex
83
the hypothalamus conatins important __ and __ centers
control and integrative
84
the hypothalamus may be stimulated by (3)
1. sensory information from cerebrum, brainstem, spinal cord
2. changes in composition of CSF and interstitial fluid
3. chemicals in circulating blood (lacks blood brain barrier)
85
__ connects the hypothalamus to the pituitary gland
infundibulum
86
what is the limbic system?
functional grouping of tracts and nuclei along border of cerebrum and diencephalon
87
4 functions of the limbic system
1. establishing emotional states
2. linking conscious, intellectual functions of cerebral cortex with unconscious and autonomic functions of brainstem
3. facilitating memory storage / retrieval
4. affecting motivation
88
what are the diencephalon components of the limbic system?
thalamus and hypothalamus
89
what part of thalamus contributes to the limbic system?
anterior thalamic nuclei from mammillary body to cingulate gyrus
90
which part os the hypothalamus contributes to the limbic system?
hypothalamic nuclei, mammillary body
91
what is the role of the hypothalamus in the limbic system?
emotions ( rage, fear, pain, sexual arousal, pleasure) and produce general alertness / excitement / or lethargy / sleep via stimulation of reticular formation
92
what are the 2 nuclei cerebral components of the limbic system?
1. amygdaloid body
| 2. hippocampus
93
___ is the interface between limbic system, sensory system, and cerebrum
amygdaloid body
94
___ plays a role in regulating heart rate , fight or flight, and linking emotions and memories
amygdaloid body
95
what is the role of the hippocampus in the limbic system?
learning, especially storage and retrieval of longterm memories
96
the basal nuclei of the cerebrum adjust and refine __
ongoing voluntary movements
97
basal nuclei of the cerebrum are masses of ___ within each cerebral hemisphere, deep to the ___
grey matter; floor of lateral ventricles
98
basal nuclei have __ control over skeletal muscle tone
subconscious
99
basal nuclei of the cerebrum help coordinate __
learned movement patterns
100
basal nuclei of cerebrum do not __ movements, but provide __
initiate; general pattern/rhythm
101
basal nuclei can have __ control or __ modification of movement
direct / indirect
102
direct control over movement by cerebral basal nuclei stimulates
motor nuclei in the brainstem
103
example of direct control by basal nuclei
control of cycles of arm/thigh while walking
104
indirect modification of movement by basal nuclei sends output to __ after synapsing in the __
cerebral cortex; thalamus
105
example of indirect modification of meovemnt
subconsciously adjust muscle tone as you begin a voluntary movement
106
what are the 5 lobes of the cerebrum?
frontal, parietal, temporal, occipital, insula
107
the central sulcus separates
frontal from parietal lobe
108
the precentral gyrus contains __ and controls __
primary motor cortex; voluntary movements
109
the postcentral gyrus contains __ and controls __
primary somatosensory cortex; conscious awareness of somatosensory information
110
each hemisphere receives sensory information from and sends commands to ___ side of the body
opposite
111
crossing over occurs in the __ and __
brainstem and spinal cord
112
the boundaries of the cerebral hemispheres are well-defined (t/f)
false
113
the cerebral cortex is divided into 6 functional categories:
1. motor cortex
2. sensory cortex
3. visual cortex
4. auditory cortex
5. olfactory cortex
6. gustatory cortex
114
each sensory and motor region connected to nearby __
association area
115
an association area is a region that
interprets incoming data or coordinates motor response
116
the primary motor cortex directs __ movement by controlling motor neurons in the ___
volunatary; brainstem / spinal cord
117
which cortex is responsible for coordinating learned movements?
premotor cortex
118
the premotor cortex has which association area?
somatic motor
119
the primary somatosensory cortex receives sensory information from
receptors of touch, pain, pressure, vibration, temperature
120
the somatosensory association area monitors activity in ___ cortex and recognizes __
primary somatosensory; different sensations
121
the gustatory cortex is located in the
insula
122
function of the auditory association area
recognizes different sounds (such as speech/tones)
123
the primary visual cortex receives visual information from
lateral geniculate bodies
124
function of the visual association area
monitors activity and patterns in visual cortex and interprets the information
125
what are the 5 functions of integrative centers?
1. receive information from association areas
2. direct motor activities
3. perform analytical functions
4. in lobes / cortical areas of both cerebral hemispheres
5. language areas typically associated with left hemisphere
126
the Broca's areas is the ___ area
motor speech
127
which area regulates breathing / vocalization patterns for normal speech
Broca's area
128
if the Broca's area is damaged, can ___ but cannot __
make sounds, but not words
129
the ___ cortex integrates information from sensory association areas and performs intellectual functions
prefrontal
130
the frontal eye field controls___
learned eye movements
131
example of function performed by frontal eye field
scanning lines of text
132
which area is associated with language comprehension?
Wernicke's area
133
the wernicke's area receives information from ___ association areas
somatosensory
134
which area plays a key role in personality by linking sensory information to visual and auditory memories
Wernicke's area
135
what is hemispheric lateralization?
regional specialization of each hemisphere
136
the left hemisphere contains the specialized __ areas
language, math
137
the premotor cortex for hand movements is larger on the ___ side of the hand you write with
opposite
138
the right cerebral hemisphere analyzes ___ information and relates ___ to it
sensory; body
139
interpretive centers for identifying familiar objects by touch, smell, sight, taste is located in the ___ cerebral hemisphere
right
140
interior of cerebral hemispheres mostly consists of ___ matter
white
141
white matter is grouped based on __
function
142
____ connect areas in the same cerebral hemisphere
association fibers
143
____ connect the two cerebral hemispheres
commissural fibers
144
what is the most important band of commissural fibers?
the corpus callosum
145
the corpus callosum allows for ___ between through the two hemispheres
communication / coordination
146
what is the anterior commissure?
smaller tract connecting the 2 hemispheres
147
the anterior commissure becomes more important if
the corpus callosum is damaged
148
what is the function of projection fibers?
link cerebral cortex to diencephalon, brainstem, cerebellum, and spinal cord
149
all projection fibers pass through the ___
diencephalon
150
neural function depends on __ events
electrical
151
electrical activity of all the neurons in the brain generates __ measurable by ___ placed on the scalp
an electrical field; electrodes
152
what is an EEG?
electroencephalogram that tracks electrical patterns "brain waves"
153
alpha waves occur__ and disappear
in healthy awake adults who close their eyes; during sleep or with specific concentration
154
beta wave have ___ frequency than alpha waves
higher
155
beta waves appear in people who are
concentrating, under stress or tension
156
theta waves appear transiently in __
normal sleep in adults
157
theta waves are usually seen in
children and intensely frustrated adults
158
delta waves have ___ amplitudes and __ frequency
large; low
159
delta waves are found normally in ___
sleep in all ages
160
delta waves in infants is a sign of
incomplete cortical development
161
delta waves in an awake adult is a sign of
tumor, vascular block, inflammation damaged part of the brain
162
how many pairs of cranial nerves are there ?
12
163
CN I
olfactory nerve
164
CN II
optic nerve
165
CN III
oculomotor nerve
166
CN IV
trochclear nerve
167
CN V
trigeminal nerve
168
CN VI
Abducens nerve
169
CN VII
facial nerve
170
CN VIII
vestibulocochlear nerve
171
CN IX
glossopharyngeal nerve
172
CN X
vagus nerve
173
CN XI
accessory nerve
174
CN XII
hypoglossal nerve
175
sensory receptors
specialized cells / processes that alert CNS about conditions in / out of your body
176
general senses
temperature, pain, touch, pressure, vibration, position
177
where are general sense receptors found in the body?
scattered throughout
178
sensory pathways begin at __ and end ___
begin at peripheral receptors and end in CNS
179
sensations
information carried by a sensory pathway
180
perception
conscious awareness of a sensation
181
receptive field
area monitored by a single receptor cell
182
the larger the receptor field, the ___ able to localize stimulus
less likely
183
what are free nerve endings?
tips of dendrites of sensory neurons
184
what is the simplest form of receptor?
free nerve endings
185
describe the receptor specificity in free nerve endings
respond to many stimuli, so not much
186
example of free nerve endings
pain receptors stimulated by chemicals, pressure, temperature, or trauma
187
nociceptors are ___ receptors
pain
188
nociceptors are free nerve endings with __ receptive fields and __ sensitivity
large; broad
189
what 2 types of axons carry pain information?
1. myelinated A type
| 2. unmyelinated C type
190
myelinated A type axons carry __ pain
fast
191
in myelinated A type axons, pain quickly reaches ____ for conscious awareness, triggering ___ reflexes
primary somatsensory cortex; somatic
192
with type A pain, you can usually
locate the stimulus
193
unmyelinated C type pain is ___ pain
slow (burning, aching)
194
C type pain results in
general activation of reticular formation and thalamus
195
with C type pain you are able to
tell youre in pain, but cant pinpoint past a general area
196
thermoreceptors are free nerve endings in the __, __, ___, and ___
dermis, skeletal muscles, liver, hypothalamus
197
cold receptors are 3-4 times more ___ than warm receptors
numerous
198
what are the differences beteen cold and warm receptors?
none
199
chemoreceptors respond to ___ and ___ substances dissolved in ___ such as ___
water and lipid soluble; body fluids (interstitial fluids, blood, CSF)
200
mechanoreceptors respond to
physical distortion of their PM
201
what are the 3 types of mechanoreceptors?
1. proprioceptors
2. baroreceptors
3. tactile receptors
202
proprioceptors monitor
position of joints/muscles
203
what is the most complex type of general sensory receptor?
proprioceptor
204
example of a proprioceptor
muscle spindle
205
baroreceptors detect
pressure changes in BV, digestive, respiratory, and urinary tracts
206
tactile receptors provide sensations of
touch, pressure, and vibration
207
tactile receptors include
fine and crude touch/pressure receptors
208
receptors are categorized by nature of
their response to stimulation
209
tonic receptors are ___ adapting, always __
slow; active
210
in tonic receptors, action potential reflects
level of stimulation
211
phasic receptors are __ adapting and nomally
fast; inactive
212
phasic receptors become active for a short time when
a change occurs in what they are monitoring
213
adaption
reduction in sensitivity with constant stimulus
214
what are the 2 types of adaption?
1. peripheral
| 2. central
215
peripheral adaption occurs when ___ changes: first responds ___, then activity ___
level of receptor activity; strongly, the activity declines
216
peripheral adaption is especially characteristic to ___ receptors
phasic
217
example of peripheral adaption
temperature is not noticed until it changes
218
central adaptation occurs along ____ and involves
sensory pathways in CNS; inhibition of nuclei along sensory pathway
219
example of central adaption
new smell stops after it is initially detected, but neurons still send signals
220
tactile sensory receptors are ___ responding to ___
mechanoreceptors ; touch, pressure, vibration
221
there is a great diversity of tactile sensory receptors in
the skin
222
6 types of tactile receptors in the skin
1. free nerve endings
2. root hair plexus
3. tactile discs
4. tactile corpuscles
5. lamellar corpuscles
6. bulbous corpuscles
223
what is the most common tactile receptor in the skin?
free nerve ending
224
free nerve endings are ___ specific and respond to __
not; touch, pressure, pain, temperature
225
root hair plexus monitors __
distortion/movement of hair follicle
226
displacement of hair distorts ___ and generates
sensory dendrites; action potentials
227
root hair plexus adapt __
rapidly
228
tactile discs monitor
fine touch and pressure
229
tactile discs have extremely ___ tonic receptors
sensitive
230
tactile discs have ___ receptive fields
very small
231
tactile corpuscles detect
fine touch, pressure, low frequency vbration
232
tactile corpuscles adapt within __
1 second
233
tactile corpuscles are abundant in
eyelids, lips, fingertips
234
lamellar corpuscles are sensitive to
deep pressure
235
lamellar corpuscles are ___ adapting and most sensitive to ___
fast; pulsing or high-frequency vibration
236
lamellar corpuscles have ___ receptors
large
237
lamellar corpuscles are abundant in
fingers, fasciae, joint capsules, some viscera (mesenteries, pancreas, urethra, and bladder)
238
bulbous corpuscles are sensitive to
pressure and distortion of deep dermis
239
tension of dermis stimulates
dendrite
240
tonic receptors have __ adaption
little
241
somatotopy
functional map of primary somatosensory cortex
242
sensory hommunculus
somatotope showing the relative size of cortex devoted to any specific body area
243
motor homunculus
functional map of primary motor cortex
244
proportions reflect number of ___and degree of ___ in body region
motor units; fine motor control
