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7/29/2019 Ch 49 Nervous Systems
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The ability of cells to respond to
the environment has evolvedover billions of years
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• Nerve nets.
Nervous systems show diversepatterns of organization
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• With cephalization come more complex
nervous systems.
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• Functional composition of the PNS.
Fig. 48.17
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Parasympathetic and SympatheticNervous System:• A subdivision of the PNS
• Not under conscious control
• Work antagonistically
• Controlled by medulla oblongata and
hypothalamus
• Peripheral nervous system thatsupplies stimulation via motor nerves
to smooth and cardiac muscle and to
glands
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neurotransmitter is norepinephrine, fightor flight
E = exercise, excitement, emergency, and
embarrassment
neurotransmitter is acetylcholine
D = digestion, deification, diuresis (urinating)
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7/29/2019 Ch 49 Nervous Systems
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Fig. 48.20
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cerebrum corpuscallosum
thalamus
cerebellum
medullaoblongata
hypothalamus
pituitarypons
spinal cord
Pineal gland
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Cerebrum
• Involved with higher brain functions.• Processes sensory information.
• Initiates motor functions.
• Integrates information.
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• The
cerebrum is
divided into
frontal,
temporal,
occipital,and parietal
lobes.
Regions of the cerebrum arespecialized for different functions
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• Frontal lobe. – Contains the primary motor cortex.
• Parietal lobe. – Contains the primary somatosensory cortex.
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Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Fig. 48.25
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• Integrative Function of the Association Areas.
– Much of the cerebrum is given over to
association areas. • Areas where sensory information is integrated
and assessed and motor responses areplanned.
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• The brain exhibits plasticity of function.
– For example, infants with intractable
epilepsy may have an entire cerebralhemisphere removed.
• The remaining hemisphere can provide thefunction normally provided by bothhemispheres.
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• Lateralization of Brain Function.
– The left hemisphere.
• Specializes in language, math, logic operations, andthe processing of serial sequences of information, andvisual and auditory details.
• Specializes in detailed activities required for motor
control. – The right hemisphere.
• Specializes in pattern recognition, spatial relationships,nonverbal ideation, emotional processing, and the
parallel processing of information.
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Fig 49-17
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Fig. 49-17
Generatingwords
Max
Speakingwords
Hearingwords
Seeingwords
Min
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• Language and Speech.
– Broca’s area. • Usually located in the left hemisphere’s frontal lobe • Responsible for speech production.
– Wernicke’s area. • Usually located in the right hemisphere’s temporal lobe
• Responsible for the comprehension of speech.
– Other speech areas are involvedgenerating verbs to match nouns, grouping
together related words, etc.
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• Emotions.
– In mammals, the limbic system is composed
of the hippocampus, olfactory cortex, inner portions of the cortex’s lobes, and parts of the
thalamus and hypothalamus.
• Mediates basic emotions (fear, anger), involved in
emotional bonding, establishes emotional memory
– For example,
the amygdala
is involved in
recognizingthe emotional
content of
facial expression.
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• Memory and Learning.
– Short-term memory stored in the frontal
lobes.
– The establishment of long-term memory
involves the hippocampus.
• The transfer of information from short-term to
long-term memory.
– Is enhanced by repetition (remember that when you are
preparing for an exam).
– Influenced by emotional states mediated by the
amygdala.
– Influenced by association with previously stored
information.
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– Different types of long-term memories arestored in different regions of the brain.
– Memorization-type memory can be rapid.• Primarily involves changes in the strength of
existing nerve connections.
– Learning of skills and procedures is slower.• Appears to involves cellular mechanismssimilar to those involved in brain growth anddevelopment.
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• Human Consciousness.
– Brain imaging can show neural activity
associated with:• Conscious perceptual choice
• Unconscious processing
• Memory retrieval• Working memory.
– Consciousness appears to be a whole-brain phenomenon.
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R h d l
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• The mammalian PNS has the ability to repair
itself, the CNS does not.
– Research on nerve cell development and
neural stem cells may be the future of
treatment for damage to the CNS.
Research on neuron developmentand neural stem cells may lead to
new approaches for treating CNSinjuries and diseases
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• Neural Stem Cells.
– The adult human brain does produce new
nerve cells.• New nerve cells have been found in the
hippocampus.
• Since mature human brain cells cannotundergo cell division the new cells must havearisen from stem cells.
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Thalamus
• Relay center for sensory tracts
from the spinal cord to thecerebrum.
• Contains centers for sensation
of pain, temperature, and touch.• Involved with emotions andalerting or arousal mechanisms.
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• The Reticular System, Arousal, and Sleep.
– The reticular activating system (RAS) of
the reticular formation.
• Regulates sleep
and arousal.
• Acts as asensory filter.
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Fig. 48.21
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– Sleep and wakefulness produces patterns
of electrical activity in the brain that can be
recorded as an electroencephalogram(EEG).
• Most dreaming
occurs duringREM (rapid
eye movement)
sleep.
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Fig. 48.22b-d
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Hypothalamus
• autonomic control center- blood pressure,rate and force of heart contraction, center for emotional response and behavior
• body temperature• water balance and thirst• sleep/wake cycles
• appetite• sexual arousal• control of endocrine functioning: Acts on the pituitary gland through the
release of neurosecretions.
Regulates:
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Hypothalamus
Pituitary
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Pituitary
Midbrain
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• Cerebellar peduncles
• Tectum
• Superior colliculi• Inferior colliculi
• Substantia nigra
• Red nuclei
Midbrain
thalamus
Red nucleus
Substantia nigra
Posterior
Anterior
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Midbrain
• Contains ascending and descendingtracts to the cerebrum andthalamus.
• Reflex center for eye muscles.• Also involved with processing visual
and auditory information (connects
head movements with visual andauditory stimuli).
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Pons
• Connects the two
halves of the
cerebellum.
• Regulates breathing.
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Medulla Oblongata
• Composed of nerve tractsto and from the brain
(these tracts cross over
left to right and right to left)• May be regarded as an
extension of the spinal
cord• Almost all of the cranial
nerves arise from this
region
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Medulla Oblongata
Contains control centers for many subconscious
activities
• Respiratory rate• Heart rate
• Arteriole constriction
• Swallowing• Hiccupping
• Coughing
• Sneezing
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Cerebellum
• Controls and coordinatesmuscular activity.
• Important in equilibrium,
posture and movement.
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On Old Olympus Towering Tops A Fat Voracious German Viewed A Hop
1. Olfactory- smell
2. Optic- vision
3. Oculomotor- 4 of the 6 extrinsic eye muscles
4. Trochlear- extrinsic eye muscles
5. Trigeminal- sensory fibers to the face and motor fibers to
the chewing muscles
6. Abducens- controls eye muscles that turn the eye laterally
7. Facial- facial expression
8. Vestibulocochlear- hearing and balance
9. Glosopharyngeal- tongue and pharynx
10.Vagus- parasympathetic control of heart, lungs &
abdominal organs
11.Accessory- accessory part of vagus nerve, neck & throat
muscles
12.Hypoglossal- moves muscles under tongue
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OlfactoryOptic
Oculomotor
Trochlear
Trigeminal
Abducens
Vestibulocochlear Glossopharyngeal
Vagus Accessory Hypoglossal
Facial
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Degenerative brain diseases
• Schizophrenia
• Parkinson’s
• Alzheimer’s • Huntington’s Chorea
• MS
• Epilepsy
P ki ’ di
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Parkinson’s disease
• Substantia nigra in midbrain• Dopamine
- affects brain processes controlling:
• movement• balance
• walking
• emotional response• ability to experience pleasure
and pain.
P ki ’ di
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Parkinson’s disease Causes:
• Genetics• Environmental chemicals (e.g., PCBs)
• Thyroid disorders
• Repeated head injury
Symptoms of Parkinson's Disease: • resting tremor on one side of the body
• generalized slowness of movement (bradykinesia)
• stiffness of limbs (rigidity)• gait or balance problems (postural dysfunction).
P ki ’ di
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Parkinson’s disease
Treatments:• L-dopa
• Deprenyl
• Deep brain stimulation w/electrodes
• Fetal tissue
P ki ’ di
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Parkinson’s disease
F-Dopa deficiency
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Alzheimer’s Disease
Results in dementia
• 5-15% over age 65• 50% over age 85
Associated with :
• Acetylcholine shortage• Amyloid plaques
• Neurofibullary tangles
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PET Scans
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PET Scans