The Brain

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Chapter 14
The Brain and Cranial Nerves
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The cranial nerves
CN I CN II CN III CN IV CN V CN VI CN VII CN
VIII CN IX CN X CN XI CN XII
Olfactory Optic Occulomotor Trochlear Trigeminal A
bducens Facial Accoustic Glossopharyngeal Vagus Sp
inal Accessory Hypoglossal
On Old Olympian Towering Tops A Finn And German Vi
ewed Some Hopps
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A Quick brain overview
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cerebrum
cerebral hemispheres neural cortex (gray
matter) gyri - ridges sulci - depressions fissures
fig. 14-1
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Brain landmarks
cerebrum
conscious thoughts sensations intellect memory com
plex movements
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cerebellar hemispheres coordinates complex muscle
actions
cerebellum
fig. 14-1
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thalamus relay, process sensory
info hypothalamus emotions, autonomics, hormones
pituitary gland
midbrain -
process visual hearing info
pons
fiber tract
medulla oblongata
autonomics, etc.
fig. 14-1
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embryology
brain
tube wall cavity
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embryology
five brain vesicles
telencephalon diencephalon mesencephalon metenceph
alon myelencephalon
cerebrum thalamus mid- cerebellum/pons medulla ob.
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embryology
five brain vesicles
all hollow fluid-filled spaces ventricles with
CSF (cerebrospinal fluid)
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brain ventricles
telencephalon diencephalon mesencephalon metenceph
alon myelencephalon
lateral v third v cerebral aqueduct fourth
v fourth v
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cerebral aqueduct
fig. 14-2
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ventricles (and central canal of the spinal
cord) are all connected to each other all
filled with CSF
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brain is surrounded by
1. bones of cranium
2. meninges
dura mater arachnoid mater pia mater
3. CSF
inside and around outside
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CSF
cushion brain/spinal cord supports
brain transport nutrients/wastes
produced by lining of cavities circultates in
and around brain
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blood supply to brain
neural tissue does not have reserves of glucose,
O2 etc.,
has a very good blood supply
internal carotid arteries vertebral arteries
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blood supply to brain
CVA (stroke)
blood supply to part of the brain is cut
off tissue begins to die infarction
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blood supply to brain
blood-brain barrier
restrict access to neural tissue of most
molecules capillary endothelial cells tight
junctions astrocyte foot processes
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fig. 12-4
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AP Jeopardy
What is a nucleus ?
The cellular organelle containing the DNA
What is a nucleus ?
A collection of NCB in the CNS
(nerve cell bodies)
What is a ganglion ?
A collection of NCB in the PNS
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review
cranial nerves name and number brain 5 vesicles
and fates CSF in and around CNS good blood
supply to brain blood / brain barrier nucleus vs.
ganglion
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The Brain
medulla oblongata
autonomic reflexes cranial nerve nuclei relay
stations
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medulla oblongata
all info
passes through
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medulla oblongata
autonomic reflexes
heart rate heart contraction strength peripheral
blood flow
respiration rate
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medulla oblongata
motor nuclei for cranial nerves
CN IX, X, XI, XII
muscles of pharynx, neck, back viscera
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medulla oblongata
sensory nuclei for cranial nerves
CN VIII
from inner ear
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medulla oblongata
relay stations
nucleus gracilis nucleus cuneatus
somatic sensory
visceral sensory
solitary nucleus
somatic motor
olivary nucleus
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pons
links cerebellum with everything else
lots of tracts passing through
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pons
cranial nerve nuclei
CN V, VI, VII
motor
jaw and some face muscles
sensory
CN VIII
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cerebellum
adjust postural muscles of body fine-tune motor
movements
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fig. 14-7
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Purkinje cells in cortex
each one can receive input from up to 200,000
synapses
proprioception visual tactile balance auditory
input from
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fig. 14-7
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ataxia
(lack of order) a disturbance in muscular
coordination
physical damage stroke drugs (EtOH)
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mesencephalon
corpora quadrigemina
superior colliculi inferior colliculi
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mesencephalon
relay for
corpora quadrigemina
visual
superior colliculi
reflex center for eyes, head, neck response to
bright light
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mesencephalon
relay for
corpora quadrigemina
superior colliculi inferior colliculi
visual auditory
reflex center for head, neck, trunk response to
loud noise
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mesencephalon
tegmentum
red nucleus substantia nigra
control arm position and background muscle
tone regulates basal nuclei
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mesencephalon
headquarters of RAS
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diencephalon
epithalamus pineal gland melatonin d/n thalamus re
lay info to basal nuclei and cerebrum hypothalamu
s control and integration hormones, emotions
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diencephalon
thalamus R L separated by third v. 5 groups of
nuclei anterior medial ventral posterior lateral
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diencephalon
thalamus anterior
part of limbic system (later, emotions/motivation)
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diencephalon
thalamus medial
connect emotional centers of hypothalamus with
frontal lobes of cerebrum
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diencephalon
thalamus ventral
info from basal nuclei to motor areas of
cerebrum relay senses to cerebrum
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diencephalon
thalamus posterior
integrate, relay sensory information to
cerebrum LGN visual MGN auditory
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diencephalon
thalamus lateral
feeback loops with limbic s emotions integration
of senses
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fig. 14-9
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diencephalon
hypothalamus
below thalamus optic chiasm mamillary
bodies infundibulum
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fig. 14-10
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diencephalon
hypothalamus
subconscious control of skeletal muscle (facial
expression with emotions)
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diencephalon
hypothalamus
control autonomic centers of medulla and
pons heart rate, bp, resp, digest
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diencephalon
hypothalamus
coordinate nervous and endocrine systems
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diencephalon
hypothalamus
produce two hormones
ADH Oxytocin
antidiuretic hormone smooth muscle contraction
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diencephalon
hypothalamus
produce emotions/drives
hunger, thirst
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diencephalon
hypothalamus
Coordinate Voluntary and Autonomic functions
Take out a sheet of paper for a surprise 300
point quiz
increased heart rate, breathing, etc.
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diencephalon
hypothalamus
regulate body temperature by controlling blood
flow to the skin
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diencephalon
hypothalamus
controls circadian rhythms
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Early April Poster session (Centrum)
Also other Biology seminars
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The limbic system
nuclei and tract along border of cerebrum and
diencephalon
functions
establish emotional states link conscious with
unconscious facilitate memory storage/recall
a motivational system
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The limbic system
limbic lobe of cerebrum (1)
cingulate gyrus dentate gyrus parahippocampal
gyrus
gyri conceal hippocampus (2)
learning long-term memory
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fig. 14-11
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fig. 14-11
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The limbic system
amygdaloid body (3)
interface between limbic- cerebrum sensory
systems regulate heart rate (sym) link
emotions/memories
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The limbic system
fornix
fiber tract between hippocampus and hypothalamus
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table 14-7
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The cerebrum
largest region of brain
conscious thoughts intellectual
functions processing of sensory and motor
info surface is gray matter cerebral cortex
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The cerebrum
hemispheres (R and L)
separated by longitudinal fissure divided into
lobes
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fig. 14-12
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The cerebrum
hemispheres (R and L)
receive/send info to opposite side of body
have different functions
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The cerebrum
white matter fibers
association interconnect - same
side commissural interconnect R and
L projection fibers to other structures
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label corpus callosum
fig. 14-13
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The cerebrum
basal nuclei
several nuclei caudate nucleus lentiform
nucleus globus pallidus putamen
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fig. 14-14
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The cerebrum
basal nuclei
subconscious control of skeletal muscle
tone coordination of learned movements
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The cerebrum
basal nuclei
inhibited by dopamine from the substantia nigra
if s.n. is destroyed or dopamine levels decline
basal nuclei are overactive
increase in muscle tone
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The cerebrum
basal nuclei
Parkinsons disease
difficulty starting muscle movements
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fig. 14-12
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table 14-8
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The cerebrum
primary motor cortex primary sensory cortex
frontal lobe pyramidal cells (UMN) piano
analogy parietal lobe touch, pain,
pressure, taste, vibrations, temp. (if thalamus
relays it)
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motor
sensory
mapping
fig. 14-15
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The cerebrum
other sense cortex
visual auditory olfactory gustatory
occipital temporal temporal frontal
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fig. 14-15
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The cerebrum
association areas
interpret incoming information
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fig. 14-15
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The cerebrum
association areas
interpret incoming information
e.g., visual association area associate visual
symbols with object C A R
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The cerebrum
association areas
interpret incoming information
visual association area
someone with damage here would see the symbols
C A R but would have no idea that they mean
something
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The cerebrum
premotor cortex
coordination of learned movements repetition
programs in patterns of stimulation back to
the piano analogy
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The cerebrum
integrative centers
receive lots of information direct extremely
complex motor activities, analytical functions,
some centers are restricted to one side
hemispheric lateralization
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The cerebrum
integrative centers
for example
general interpretive center (aka Wernickes area
left side)
receives input from all sensory areas
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The cerebrum
integrative centers
for example
general interpretive center (aka Wernickes area
left side)
damage affects ability to interpret what is seen
and heard
sit here
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fig. 14-15b
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The cerebrum
integrative centers
for example
speech center (aka., Brocas area left side)
coordinates activity of pharynx, tongue, cheeks,
jaw, lips, etc.,
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The cerebrum
integrative centers
for example
prefrontal cortex
receives and coordinates input from all
association areas
performs abstract intellectual functions, predicti
ng consequences
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The cerebrum
integrative centers
for example
prefrontal cortex
generates feelings of frustration, anxiety,
tension
severe its connections and remove those feelings
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The cerebrum
integrative centers
for example
prefrontal cortex
prefrontal lobotomy
cure mental patients
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The cerebrum
hemispheric lateralization
each hemisphere has specific functions not done
by the other side
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fig 14-6
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The cerebrum
Monitoring brain activity
directly stimulate areas behavioral changes with
injury Phineas Gage PET scan, MRIs
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The cerebrum
Monitoring brain activity
electrical activity EEG (electroencephalogram)
(brain waves)
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The cerebrum
Monitoring brain activity
electrical activity different wave
patterns alpha beta theta delta
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normal resting adult concentration,
stress children, frustrated adults deep sleep,
injury
fig 14-17
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The cerebrum
Monitoring brain activity
electrical activity
seizure
temporary, drastic changes in electrical activity
of cerebrum
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epilepsy
clinical conditions caused by a seizure
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epilepsy
and cutting corpus callosum split brain