Chapter 9 powerpoint file

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POWERPOINT® LECTURE SLIDE PRESENTATION
by LYNN CIALDELLA, MA, MBA, The University of Texas at Austin
Additional Text by J Padilla exclusively for physiology at ECC
UNIT 2
9
PART A
The Central Nervous
System
HUMAN PHYSIOLOGY
AN INTEGRATED APPROACH
DEE UNGLAUB SILVERTHORN
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FOURTH EDITION
Emergent Properties
 Emergent properties of neural networks:
 Inexplicable properties –the structural components of
a neuron cannot explain the complex responses
produced during neural processing/integration
 Neuron circuits – a single neuron cannot fully
perform its function, thus its optimal performance has
to be within a circuit
 Plasticity- allows the brain to change from circuit to
circuit depending on sensory input and past experience
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Arrangement of Nervous System Pathways
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Spinal Cord Protection
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Neural Tissue: Metabolic Needs
 Oxygen
 Passes freely across blood-brain barrier
 Brain receives 15% of blood pumped by heart
 Glucose
 Brain responsible for about half of body’s glucose
consumption
 Membrane transporters move glucose from plasma
into the brain interstitial fluid
 Hypoglycemia leads to confusion, unconsciousness,
and death
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Spinal Cord: Overview
Central nervous system,
posterior view
The spinal cord has
two enlargements
and ends in the
lumbar region.
Spinal nerves are
part of the PNS and
carry both sensory
and motor neuron
fibers.
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Figure 9-4a
Spinal Cord: Anatomy
Specialization
in the
spinal cord
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Figure 9-7a
Spinal Cord: Anatomy
Propriospinal
tracts remain
within
the cord
Tracts carry
information in
only one
direction along
a specified
path of
interneuron
connections.
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Figure 9-7b
Spinal Cord: Anatomy
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Figure 9-7c (1 of 2)
Spinal Cord: Integrating Center
Simple reflexes
can be
integrated by the
spinal cord
without input
from the brain
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Figure 9-8
Anatomy of the Brain
Oldest and
most
primitive
region of
the brain.
Ascending
and
descending
tracts pass
through the
brain stem.
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Figure 9-9d
The Brain: The Brain Stem
 Divided into three regions- medulla oblongota, pons, and
midbrain
 Each region contains cranial nerves & nuclei that control
autonomic function
 Many nuclei are associated with reticular formationwhite fibers what interconnect different areas throughout
the brain.
 Medulla Oblongata- controls involuntary funtions and
connects to spinal cord.
 Somatosensory (ascending) and corticospinal (descending)
tracts in white matter
 Pyramids- area where the fibers cross over thus the many
functions are controlled by the opposite side of the brain.
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Reticular Formation
2. Reticular formationThese are clusters of
neurons (white matter)
that run through the
core of the brainstem.
Involved in maintaining
the brain alert, arousal,
and sleep. It also
control visceral
functions like heart rate
& vomiting. A motor
tract goes down the
spinal cord and is
involved in movement.
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10 of 12 cranial
nerves
originate along
brain stem.
Create flash
cards for the
nerves on
table 9.1, be
able to
identify their
location,
origin &
destination,
function,
type of
information
each nerve
carries
Cranial Nerves
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Mid-sagittal View of the Brain
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The Brain: Diencephalon
Thalamus is a relay
and integrating station
Hypothalamus is the
homeostasis center
and also controls
behavior related to
homeostasis
Two endocrine
structures: pineal and
pituitary gland.
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Figure 9-10
The Brain: Hypothalamus
The
hypothalumus
contains
many nuclei
that focus on
the specific
functions
listed here.
Make
flashcards of
the info on
this table
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The Brain: Cerebellum
Lateral view of brain
The cerebellum coordinates movement- also processes
sensory information and motor input from the cerebrum; it
smoothes and coordinates movement.
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Figure 9-9b
Cerebral Mid-Sagittal View
Corpus
Callosum is
white matter
that connects
the two
hemispheres
Sulci= grooves
Gyri=
convolutions
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Figure 9-9c
White Matter in the cerebrum contains fibers that
connect various brain areas
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Gray Matter of the Cerebrum
Cerebral cortex is
30 layers thick and
it’s the site of
higher brain
function.
The level of
processing is
directly related to
the surface area
Basal ganglianeural calculators
that control
movement
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Figure 9-11
The Brain: The Limbic System
 Emotion, memory,
learning, and visceral
responses
 Links higher cognitive
functions and
primitive emotional
responses
 Incorporates sensory
areas, basal ganglia,
and the diencephalon
(hypothalamus) relates
state of mind to
physiological
functions
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Figure 9-13
Brain Function: complex processing and
responses
 The brain may generate
information and output
signals in the absence of
external input
 Motor output is influenced
by sensory information,
cognition, and behavior.
Thus cognitive input may
influence the motor output
sent without sensory input.
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Brain Function:
Functional Areas of the Cerebral Cortex
Specialized sensations have separate designated
areas on the cortex
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Figure 9-15
Brain Function: Cerebral Cortex
 Three specializations – Sensory, Motor, and Association (cognition
and behavior).
 Sensory areas - stimulus activates sensory receptors, info travels in
ascending pathways and stops at the cerebellum or sensory areas of
cerebrum
 Sensory input translated into perception – brain’s interpretation of
various input regions
 Motor areas – info travels in descending pathways, cross-over at
brainstem or spinal cord, and reaches muscles or glands
 Direct skeletal muscle movement – initiated by cognitive system
based on input from cerebral motoer ares, cerebellum, & basal
ganglia
 Association areas  Integrate information from sensory and motor areas  Can direct voluntary behaviors – control over conscious actions
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Specialized Areas of the Cerebral Cortex
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Body map along the Precentral and Postcental Gyrus
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Brain Function: Sensory Information
 Primary somatic sensory cortex- found on the postcentral gyrus (parietal lobe)
 Skin, musculoskeletal system, and visceracomponents that send information to this region when
a stimulus activates a sensory receptor
 Somatosensory pathways – carry information of
senses in conscious awareness of general somatic
sense, damaged in brain area causes reduced
sensitivity in opposite side
 Touch
 Temperature
 Pain
 Itch
 Body position
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Brain Function: Sensory Information
 Special senses have devoted regions  Visual cortex –Occipital lobe (Visual
Assosiaction area and Visual cortex)
 Auditory cortex – Temporal lobe
(Auditory association area and
Audiotory Cortex
 Olfactory cortex- Temporal lobe
(uncus)
 Gustatory cortex – Frontal lobe
 Processed into perception – allows the
stimulus to be translated into a different
aspect (photons=colors) and “fills-in”
missing information. Perception is the
brains interpretation of sensory input and
it is not directly dictated by the input
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Brain Function: Motor Output
 Three major types
 Skeletal muscle movement
 Somatic motor division, involves voluntary actions processed at
cerebrum or reflexes processed at the spinal cord
 Neuroendocrine signals
 Hypothalamus and adrenal medulla- secrete neurohormones that
influence motor output
 Visceral responses
 Autonomic division- brains stem and diecephalon stimulate
involuntary muscle and glands to maintain involuntary actions
needed for function of internal organs and homeostasis
 Voluntary movement
 Primary motor cortex and motor association- contralateral control, also
influence by behavioral and cognitive system
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Brain Function: Cerebral Lateralization
Each lobe has special functions- these are not equally shared
by the opposite lobe. Right handed people tend to have left
hemisphere dominance.
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Figure 9-16
Brain Function Influenced by Behavioral State
 Modulator of sensory and cognitive processes – incorporates the
reticular formation, hypothalamus, limbic system, and regions of the
cerebral cortex
 Neurons known as diffuse modulatory systems- regulate brain
function by affecting attention, motivation, wakefulness, memory,
motor control, mood, and metabolic homeostasis
 In reticular formation in brain stem- most originate at brain stem and
innervate areas of the cerebrum and diencephalon, classified by
neurotransmitters used
 Four modulatory systems
 Adrenergic – secretes norepinephrine, originate at pons, modulate:
attention, arousal, sleep-wake cycles, learning, memory, anxiety, pain,
and mood.
 Serotonergic – secretes serotonin, originate at brain stem midline,
modulate pain, movement, sleep-wake cycles, mood, emotion
 Dopaminergic – secretes domamine, originate at midbrain, modulate
motor control and addictive behaviors
 Cholinergic – secrete acetylcholine, originate at cerebrum and brain
stem, modulate sensory information pathways through thalamus,
arousal,
sleep-wake
cycles,
learning,
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© 2007 Pearson
Education, Inc., publishing
as Benjamin
Cummings memory
Reticular Formation Pathways for Behavior
Systems and Corresponding Neurotransmitters
 See table 9-3 for
information on
neurotransmitter
function
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Behavioral State System: Arousal and SleepWake Cycles
 Consciousness- a state of arousal in which the brain is aware of
self and environment
 Reticular formation- actively interacting through ascending tracts
 Anesthetics- block signals from reaching the reticular formation
 Electroencephalograms (EGG)
 Dectect level of activity of cerebral cortex neurons used electrodes
 Awake State- various stage of awareness
 Uncoordinate firing of cortical neurons due to ascending signals in
reticular formation results in low-amplitude high-frequency waves
 As awareness declines signals the frequency of waves declines and
amplitute increases
 Sleep- major rest period for the body, no external interaction, easily
reversible, brain is as active as when awake, sleep inducing factors
also boost immunity
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Behavioral State System: States of Arousal
Electroencephalograms
(EEGs) and the sleep
cycle
Wave frequency
lessens and
amplitude increaes
as arousal
diminshes
During sleep the brain
cycles multiple
types between all
stages
Delta waves are high
amplitude, low
frequency
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Figure 9-20a
Behavioral State System: States of Arousal
 Four stages with two major phases
 Slow-wave sleep – delta waves,
 Adjust body without conscious commands
 REM sleep
 Brain activity inhibits motor neurons to skeletal
muscle, paralyzing them –also reducing
homeostasis responses
 Dreaming takes place
 Circadian rhythm
 Suprachiasmatic nucleus- location of neurons that
signal light-dark cycle phases and responses
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Behavioral State System: Emotion and
Motivation
The link between emotions
and physiological
functions
The amygdala is the center
of emotion in the brain
Stimulus to Cerebrumcreates perception, limbic
creates emotion, cerebrum
becomes aware of
emotion while hypothalus
stimulates multiple
responses
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Figure 9-21
Behavioral/Cognitive State : Motivation
 Defined as internal signals that shape voluntary
behavior (related to survival or emotions)
 Some states known as drives create increased
arousal, goal-oriented behavior, and disparate
behavior to achieve the goal.
 Works with autonomic and endocrine responses to
maintain homeostasis
 Motivated behaviors stop
 Satiety
Pleasure is related to addictive behaviors which can be
changed if given a different motivation.
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Behavioral State System: Moods
 Similar to emotions but longer-lasting- related to
sense of being, not purely psychological, related to
sense of well-being and proper neurotransmitter
function
 Mood disorders
 Fourth leading cause of illness worldwide today
 Depression
 Sleep and appetite disturbances
 Alteration of mood and libido
 Antidepressant drugs alter synaptic transmission –
allow a neurotransmitter to remain at the synapse
longer, change the receptor, or the amount of NT
released.
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Cognitive State: Learning and Memory
 Learning has two broad types
 Associative – links two stimuli or a stimulus to a behavior
 Nonassociative- change behavior due to repeated exposure
 Habituation – do not respond to an irritant stimulus, filters
out insignificant stimulus
 Sensitization- enhanced response to irritant stimulus,
helps avoid harmful stimuli
 Memory has several types
 Short-term and long-term- combined by working memory,
consolidation turns short-term into long term. Changes in
synaptic connections are required
 Reflexive and declarative- requires unconscious (procedural)
or conscious recall (infer, compare, evaluate). Declarative
can become reflexive
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Brain Function: Memory Processing
Memory is stored as memory
traces
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Figure 9-22
Brain Function: Language
Cerebral processing of spoken and visual language
Damage to Wernicke’s causes receptive aphasia- unable to understand spoken
or visual information
Damage to Broca’s area causes expressive aphasia- can understand information but
cannot speak or write in proper order, are aware of mistakes
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Figure 9-23a

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