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Chapter 2
Nervous System
Brain
Vocabulary:
• Phrenology- study of the bumps on
the skull in order to reveal mental
ability and our character traits.
• Biological psychology- concerned
with the links between biology and
behavior
– They have helped gain better
understanding of sleep and dreams,
depression and schizophrenia, stress
and disease.
You’ve got NERVE!!
• Know your vocabulary
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Neuron
Dendrite
Axon
Myelin sheath
Action potential *
Threshold
Synapse
Neurotransmitters
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Dopamine
Serotonin
Norepinephrine
Acetylcholine (ACh)
endorphins
Nervous System
• Again with the vocabulary!
– Central nervous system (brain and
spinal cord)
– Peripheral nervous system
• Autonomic (controls self-regulated action
of internal organs and glands)
– Sympathetic (arousing)
– Parasympathetic (calming)
• Somatic (controls voluntary movements of
the skeletal muscles)
– Sensory neurons
– Interneuron– billions and billions–
complexity lies in this internal
communication system
– Motor neurons
How do neurons communicate?
• Electrical impulses (action potentials)
travel from one neuron to another across
the synapse. When axon reaches axon
terminal, it stimulates the release of
neurotransmitter molecules from sacs
called vesicles. The molecules cross the
synaptic gap and bind to the receptor
sites on the receiving neuron. This
allows electrically charged atoms to
enter the receiving neuron and excite or
inhibit a new action potential. The
sending neuron reabsorbs excess
neurotransmitter molecules, called
reuptake.
Examples
• If you touch a flame, the messages
are transmitted from your spinal
cord to muscles in your hands
which move it from the flame. This
is all occurring in the _____
nervous system.
• Peripheral
• When you later feel the pain– its
reached your brain!
• Why do neurons network?
– So they have faster, shorter
connections
How do you pick up a fork?
• You central nervous system’s hungry
brain activates and guides the muscles
of your arm and hand via your
peripheral nervous system’s motor
neurons.
• As you pick up the fork, your brain
processes the information from your
sensory nervous system, enabling it to
continue to guide the fork to your
mouth
• The functional circle starts with sensory
input, continues with interneuron
processing by the central nervous
system, and finishes with motor output.
BRAIN
• reticular activating system
: a part of the reticular formation
that extends from the brain stem to
the midbrain and thalamus with
connections distributed throughout
the cerebral cortex and that
controls the degree of activity of
the central nervous system (as in
maintaining sleep and wakefulness
and in making transitions between
the two states)
Check this out!!
• http://science.nationalgeographic.com/scie
nce/health-and-human-body/humanbody/brain-article.html?nav=A-Z
More stuff
• Glial cells– neuronal support cells that
bind neurons. They insulate the myelin
(covering) and aid in the speed of neural
transmissions
• Aphasia– impaired language. If in
Brocha’s area, patient will struggle to form
words. If in Wernicke’s area, patient may
speak meaningless words or be unable to
comprehend what is said to them.
Neurotransmitters
Endorphins– natural opiates, released in response to pain and vigorous exercise.
Feedback linking nervous
system and endocrine system
• The hypothalamus in the brain influences
secretions by the pituitary gland. The
pituitary regulates other endocrine glands,
which release hormones that influence
behavior. The hypothalamus monitors
these changes in blood chemistry and
thereby adjusts its inputs to the pituitary
gland.
Neural Communication
Neurotransmitter
molecule
Receptor site on
receiving neuron
Receiving cell
membrane
Agonist mimics
neurotransmitter
Antagonist
blocks
neurotransmitter
The Brain
 CT (computed tomography) Scan
 a series of x-ray photographs taken from different angles
and combined by computer into a composite representation
of a slice through the body; also called CAT scan
 PET (positron emission tomography) Scan
 a visual display of brain activity that detects where a
radioactive form of glucose goes while the brain performs a
given task
 MRI (magnetic resonance imaging)
 a technique that uses magnetic fields and radio waves to
produce computer-generated images that distinguish among
different types of soft tissue; allows us to see structures
within the brain
CT Scans: An x-ray of the brain.
A CT scan is essentially a computerized assembly
of several x-ray images taken from a series of
different angles. With a CT, the resolution is much
better than conventional x-rays, and the detail
that can be seen is much greater.
Tumor in
Wernicke’s Area
MRI is a noninvasive imaging technique that does not use xrays. The process involves passing a strong magnetic field
through the head. The magnetic field used is 30,000 + times that
of the earth's magnetic field. It's effect on the body, however, is
harmless and temporary. The MRI scanner can detect radiation
from certain molecules, which are present in different
concentrations in different tissues.
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PET measures the emission of positrons from the brain
after a small amount of radioactive isotopes, or
tracers, have been injected into the blood stream. A
common example is a glucose-relative with embedded
fluor-18. With this molecule, the activity of different
regions of the brain can be measured. The result is a
three-dimentional map with the brain activity
represented by colors.
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Normal Brain
ADHD Brain
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Brain Development
in First Year of Life