Download The Biology of Behavior

Unit 2: Biopsychology
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Central nervous system 
consists of the brain and the
spinal cord
◦ Brain  an organ of soft nervous
tissue contained in the skull;
functions as the coordinating center
of sensation, intellect, and nervous
activity
◦ Spinal Cord  cylindrical bundle of
nerve fibers and associated tissue
that is enclosed in the spine; connects
nearly all parts of the body to brain
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Peripheral nervous system 
made up of nerve cells that send
messages between the central
nervous system and all of the
other parts of the body
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Neurons  nerve cells that run through the
whole body and communicate with each other.
◦ 30,000 neurons can fit on a pinhead
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Each neuron contains:
◦ Cell body with nucleus
◦ Dendrites : fibers that receive messages from other
neurons
◦ Axons : fibers that send messages to other neurons
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Neurons do NOT touch; there is a gap between
them called a synapse
Messages are sent across the synapses by special
chemicals called neurotransmitters
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The use of
neurotransmitters
causes an electrical
current
◦ There is enough
electrical current in
the brain to power a
flashlight
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Serotonin
Dopamine
Achetylcholine
Norephinephrine
Endorphins
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Nerves : visible
bundles of axons and
dendrites that extend
from the brain and
spinal cord to all other
parts of the body
Responsibilities:
◦ Sensory nerves - carry
messages from body to
brain (pain, pressure,
temperature)
◦ Motor nerves – carry
messages from brain to
body to respond
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Voluntary Actions!!!
Transmits sensory messages to the central
nervous system
It is activated by touch, pain, changes in
temperature, and changes in body position
The somatic nervous system allows the body
to move or change position
It also sends messages to the muscles and
the glands and helps to maintain posture and
balance
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Involuntary Actions!!!
Regulates the body’s vital functions, such as
heartbeat, breathing, digestion, and blood
pressure
We generally do not have to think about these
activities – they occur automatically and are
essential for keeping us alive
Two divisions:
◦ Sympathetic  activated when a person is going into
action (“fight or flight”)
◦ Parasympathetic  restores the body’s reserves of
energy after an action has occurred
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The Hindbrain:
Medulla  involved in vital
functions such as heart rate,
blood pressure, and breathing
Pons  located in front of the
medulla; involved in
regulating body movement,
attention, sleep, and alertness
Cerebellum  rests under the
larger part of the brain
(cerebrum); involved in
balance and coordination
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The Midbrain:
Located between the
hindbrain and the forebrain
Involved in vision and hearing
Reticular activating system 
begins in the hindbrain, rises
through the midbrain,
continues into the lower part
of the forebrain
◦ Important for attention, sleep,
and arousal
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The Forebrain:
Thalamus  serves as a relay
point for sensory stimulation;
most of the messages coming
from the sense organs go
through the thalamus on the
way to the higher levels of the
brain
Hypothalamus  located below
the thalamus; vital to
regulation of body
temperature, storage of
nutrients, and various aspects
of motivation and emotion
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The Forebrain:
Limbic system  forms a
fringe along the inner edge of
the cerebrum; involved in
learning and memory,
emotion, hunger, sex, and
aggression
Hippocampus  involved in
memory processing
Amygdala  involved in
aggressive and fear based
responses (fight or flight)
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The Forebrain:
Cerebrum  accounts for
70% of the weight of the
human brain; surface is
wrinkled with ridges and
valleys, known as the cerebral
cortex
◦ Cerebral cortex is involved with
thinking, memory, language,
emotions, complex motor
functions, perception, and more
 Frontal
 Parietal
 Occipital
 Temporal
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The Frontal Lobe of the brain is located deep to the
Frontal Bone of the skull.
It plays an integral role in the following functions/actions:
- Memory Formation
- Emotions
- Decision
Making/Reasoning
- Personality
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It plays a major role in the following functions/actions:
- Senses and integrates sensation(s)
- Spatial awareness and perception
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The Occipital Lobe of the
Brain is located at the back of
the head
• Its primary function is the processing,
integration, interpretation, etc. of VISION
and visual stimuli.
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The Temporal Lobes are located on the sides of the
brain
• They play an integral role in the
following functions:
-
Hearing
-Organization/Comprehension of
language