Body and behavior
Chapter 6
Standards
Standard II: Biopsychological
 Biological basis of behavior
 IIA-1.1 Structure and function on neuron
 IIA- 2.1 Organization of the nervous system
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The nervous System
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Controls your movement, emotions, thinking, and behavior (almost
all you do)
Never at rest
Divided into 2 parts:
Central Nervous System (CNS) – the brain and spinal cord
Peripheral Nervous System (PNS) – nerves branching beyond
the spinal cord
Nervous System
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All parts are protected:
Brain – skull and layers of sheathing (coating)
Spinal cord – the vertebrae
Peripheral – layers of sheathing
- nerves about as thick as a pencil
Extremities – nerves get smaller and smaller
Neurons
Strips of long cells that carry messages to and from the
brain
 Carry messages by chemical-electrical signals
 Neuron can “fire” over and over again
 Messages are sent from neuron to neuron
 Body contains millions
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Parts of a neuron
4 Basic Parts:
 Dendrites
 The cell body (contains the nucleus)
 An axon
 Axon terminals
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Dendrites
 Short, thin
fibers that protrude from the cell body
 Receive impulses (messages) from other neurons
and sends them to the cell body
Axon
Single extension
 Carries impulses from cell body to the axon terminals
 Usually short, but can be several feet long
 Myelin sheath (white fatty substance) insulates and
protects the axon; can speed the transmition
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Axon Terminal
Branch out at the end of the axon
 Release neurotransmitters to stimulate dendrites of the
next neuron
 Positioned opposite of the dendrite of another neuron
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Synapse & Neurotransmitters
Synapse – space between the neurons; transmits
messages to the next neuron
 Neurotransmitters – chemicals released by neurons
- locks or excites receptors
Ex: endorphin – inhibits pain
norepinephrine – involved with memory and
learning
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Afferent, Efferent, and Interneurons
Afferent neuron (sensory neurons) – relay messages
from the sense organs (eyes, nose, skin) to the brain
 Efferent neuron (motor neurons) – send signals from the
brain to the glands and muscles
 Interneurons – processes signals only to other neurons
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Voluntary vs involuntary activites
Somatic Nervous System (SNS) – the part of
peripheral nervous system that controls voluntary activities
(skeletal muscles)
 Autonomic Nervous System (ANS) – part of the
nervous system that controls involuntary activities
 Ex: heartbeat, breathing, digestion, etc.
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The brain
 Composed
 Hindbrain
 Midbrain
 Forebrain
of 3 parts:
Hindbrain
 Rear
base of the skull; controls basic processes of life
 Includes:
 Cerebellum (behind spinal cord) – controls
posture, balance and voluntary movements
 Medulla – controls heart rate, breathing, and
reflexes
 Pons – bridge between spinal cord and brain and
produces chemicals needed for sleep
Midbrain
 Small, above
the pons
 Integrates sensory information and sends it
upwards
 Medulla and pons extends upward into the
midbrain
 Reticular Activating System (RAS)- spans across
medulla, pons, and midbrain
- Alerts brain of incoming signals and involved in
sleep/wake cycle
Forebrain
 Brains
central core
 Includes:
 Thalamus – integrates sensory information
 Hypothalamus – controls hunger, thirst, and
changes in temperature
Cerebral Cortex & Cerebrum
 Cortex
- Outer layer of forebrain
 Cerebrum – inner layer
 Higher thinking processes
 Gives you ability to learn and store complex and
abstract information
 Site of conscious thinking processes
Limbic System
 Core
of forebrain
 Regulates our emotions and motivations
 Includes: Hypothalamus, thalamus, hippocampus,
and amygdala
Amygdala - controls violent emotions such as rage and
fear
 Hippocampus: - formation of memories
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Lobes of the Brain
Cerebrum – 2 hemispheres
 Connected by: Corpus callosum
 Each hemisphere has deep grooves = regions or lobes
 Occipital lobe – vision
 Parietal lobe – body sensations
 Temporal lobe – hearing, memory, emotion, speaking
 Frontal lobe – organization, planning, creative thinking
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Hemispheres (Left & Right)
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Corpus callosum – carries messages back and forth
between the 2 hemispheres
Right: Controls left side of body
- Nonverbal, spatial, and holistic
 Left: Controls right side of body
- Verbal, Mathematical, Analytic
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Corpus Callosum
Can be severed = Split-Brain Operation
 Now have “2” brains; operate independently, no
communication between the two sides
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How Psychologists Study the Brain
 Record
electrical activity in brain – EEG
 - wires and electrodes attached to a machine
 Stimulation – “make” neurons fire on certain parts
of brain and record; determine function
 Lesions – cutting or destroying part of brain to see
if animal behaves differently
 Accidents – learn from brain trauma and tragedies
Images
 CT
scans – pinpoint injuries and deterioration
 PET scans – capture picture of brain as different
parts are being used
 MRI – able to see/study activity and structures
- combines benefits of CT and PET scans