Transcript Autonomic Nervous System

Chapter 3:
Biopsychology
3.1 Human Genetics
Evolution by Natural Selection (1859)
• Charles Darwin’s theory
• Organisms that are best adapted
to their environment are more
likely to survive, reproduce, and
pass on genetic information
Genetic Variation
• Occurs through recombination
of genetic material (sexual
reproduction)
• Chromosome
• Gene
• Deoxyribonucleic Acid (DNA)
• Mutation—a random change—
may also occur
Genetic Variation
• Genotype: An individual’s genetic makeup
• Phenotype: An individual’s inherited physical traits
Epigenetics:
Gene-Environment Interactions
• Studies of identical and fraternal twins have helped us
learn about the influence of environmental factors on
the expression of our genes, or epigenetics.
3.2 Cells of the Nervous
System
Nervous system
• The body’s
electrochemical
communication circuitry
• Made up of:
• nerve cells (neurons)—
conduct impulses
• and glial cells (glia)—
support cells
Structure of a neuron—
4 main parts
Cell body (soma): Keeps neuron
alive and determines whether it will
send a message
Dendrites: Receive information
from other neurons and transmit
toward the cell body
Axon: Extending fiber that
conducts impulses away from the
cell body to other cells
Terminal buttons: Area where
chemical messengers
(neurotransmitters) are secreted
by the neuron
How neurons communicate
• Myelin sheath wraps
around the axon of
some neurons and
speeds neural
transmission
• Neurotransmitter
enters synapse (gap
between neurons)
• Neurotransmitter
temporarily binds to
receptors—sites on
receiving neuron’s
membrane
Action Potential
The electrical
signal that travels
down the axon,
from the cell body
to the terminal
buttons, resulting
in a release of
neurotransmitter
into the synapse
3.3 Parts of the Nervous System
• Functions of
the nervous
system
include:
• Gathering
and
processing
information
• Producing
responses to
stimuli
• Coordinating
workings of
different
cells
Human Nervous System
Central Nervous
System
Peripheral Nervous
System
Brain
Somatic Nervous
System
•Housed in the skull
•Approx. 3 lbs
•Mostly comprised of
neurons and glia
Spinal cord
•Comprised of
neurons and
supportive tissue
•Runs from base of
brain down center of
back
•Protected by spinal
column
• Controls skeletal
muscles
• Allows for voluntary
movement
Autonomic Nervous
System
• Controls muscles of
internal organs
• Regulates blood
vessels, glands, internal
organs
Autonomic Nervous System
Sympathetic Nervous
System
*Arouses the body
*Uses energy
*”Fight or flight” response
Parasympathetic Nervous
System
*Calms the body
*Conserves energy
Sympathetic nervous system:
Parasympathetic nervous system:
Biofeedback
• A method for gaining
control over the
autonomic nervous
system
• One learns using
feedback from equipment
that measures biological
functions (e.g., body
temperature, blood
pressure, sweat response,
muscle tension, brain
activity)
3.4 The Brain and
Spinal Cord
Brain stem
Medulla
Responsible for certain
automatic functions
such as breathing and
heart rate
Pons
Involved in sleeping,
waking, and dreaming
Cerebellum
Regulates movement and
balance
Involved in remembering
simple skills and acquired
reflexes
Plays a part in:
•Analyzing sensory info
•Solving problems
Thalamus
Relays sensory
messages to
the cerebral
cortex
Includes all
sensory
messages
except those
from olfactory
bulb (smell)
Limbic system
• A group of brain
areas involved in
emotional
reactions,
motivated behavior,
and memory—
includes:
• Amygdala
• Hippocampus
• Hypothalamus
Amygdala
Responsible for
•Arousal
•Regulation of emotion
•Initial emotional
response to sensory
information
Hippocampus
Responsible for
storage of new
information in
memory
Enables us to
form spatial
memories for
navigating the
environment
Hypothalamus
•Involved in:
•Emotions
•Drives vital to survival
• Fear
• Hunger
• Thirst
• Reproduction
•Feeling rewarded
•Regulating autonomic
nervous system
Pituitary gland
•Small endocrine
gland which
releases hormones
and regulates other
endocrine glands
•Works in
conjunction with
hypothalamus
The endocrine system
Endocrine glands
release hormones
into the
bloodstream…
…Hormones regulate growth,
metabolism, sexual development
and behavior, and other functions.
The cerebral cortex
•Largest brain structure
•In charge of most
sensory, motor, and
cognitive processes
•Divided into two halves,
called hemispheres
Lobes of the cerebral cortex
Occipital lobes
Vision (visual cortex)
Parietal lobes
Body sensation
(somatosensory cortex)
Temporal lobes
Memory, perception, emotion,
hearing (auditory cortex)
Frontal lobes
Emotion, planning, creative thinking, personality,
and movement (motor cortex)
Phineas Gage’s frontal lobe
damage
Gage was a railroad
construction foreman
An 1848 explosion
forced a steel tamping
rod through his head
Others said he was “no
longer Gage”
Lost his job, worked as
a sideshow exhibit
Corpus callosum
• Millions of myelinated
axons connecting the
brain’s hemispheres
• Provides a pathway for
communication
• If surgically severed to
treat epilepsy, resulting
in a “split-brain”
condition, the
hemispheres cannot
communicate directly
Lateralization
Specialization
of the two
cerebral
hemispheres
for particular
operations
Motor control and the
hemispheres
• Left hemisphere
controls right side of
body
• Right hemisphere
controls left side of
body
Broca’s area
Left hemisphere
controls speech
production
What is the object in your left hand?
• If someone with a
split brain is
blindfolded and
asked what they
are holding in
their left hand,
can they do it?
Plasticity
•The brain’s
ability to change
and adapt in
response to
experience
•Reorganizing or
growing new
neural
connections
Brain imaging:
Electroencephalography(EEG)
A recording of neural activity detected
by electrodes placed on the scalp
Brain imaging: Computerized
Tomography (CT Scan)
Multiple X-rays are combined to show
cross-sections of brain tissue
Brain imaging: Positron Emission
Tomography (PET Scan)
A method for analyzing biochemical activity in
the brain, using injections of a glucose-like
substance containing a radioactive element
• Active areas have
increased blood flow.
• Sensors detect
radioactivity.
• Different tasks show
distinct activity patterns.
Brain imaging: Magnetic
Resonance Imaging (MRI)
Method for studying body and brain tissue
• Magnetic fields allow for
detection of energy/radio
waves.
• Computer calculates tissue
density from radio waves.
• Provides clear 3D images
• fMRI provides pictures of
activity by measuring blood
flow