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Chapter 2
Biological Foundations
and the Brain
The Genetic Perspective
• Chromosomes
• threadlike structures located in the nucleus of each
human cell
• Deoxyribonucleic Acid (DNA)
• a complex molecule that contains genetic
information
• Genes
• short segments of DNA that are the units of heredity
information
Copyright © 1999 by The McGraw-Hill Companies, Inc.
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Perspectives on Nature
and Nurture
• Environment
– all of the surrounding conditions and influences
that affect the development of living things
• Nurture
– an organism’s environmental experiences
• Nature
– an organism’s biological inheritance
Copyright © 1999 by The McGraw-Hill Companies, Inc.
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Perspectives on Nature
and Nurture
• Dominant-recessive genes principle
– the principle that if one gene of a pair is
dominant and the other is recessive, the
dominant gene exerts its effect, overriding the
potential influence of the recessive gene. A
recessive gene exerts its influence only if both
genes of the pair are recessive
Copyright © 1999 by The McGraw-Hill Companies, Inc.
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The Evolutionary Perspective
• Natural selection
– the evolutionary process that favors the
individuals within a species that are best
adapted to survive and reproduce in their
particular environment
• Evolutionary psychology
– emphasizes the roles of evolution and
psychological mechanisms in adaptive behavior
Copyright © 1999 by The McGraw-Hill Companies, Inc.
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The Nervous System
Copyright © 1999 by The McGraw-Hill Companies, Inc.
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The Nervous System
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Neurons
Central Nervous System (CNS)
Peripheral nervous system
Somatic nervous system
Autonomic nervous system
Copyright © 1999 by The McGraw-Hill Companies, Inc.
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The Nervous System
• Sympathetic nervous system
– the division of the autonomic nervous system
that arouses the body
• Parasympathetic nervous system
– the division of the autonomic nervous system
that calms the body
Copyright © 1999 by The McGraw-Hill Companies, Inc.
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Neural Transmission
• Afferent nerves
– sensory nerves that carry information to the
brain
• Efferent nerves
– motor nerves that carry the brain’s output
• Interneurons
– CNS neurons that mediate sensory input and
motor output
Copyright © 1999 by The McGraw-Hill Companies, Inc.
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Structure of the Neuron
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Cell body
Dendrite
Axon
Myelin sheath
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The Nerve Impulse
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Ions
Resting potential
Action Potential
All-or-none principle
Copyright © 1999 by The McGraw-Hill Companies, Inc.
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Synapses and Neurotransmitters
• Synapses
• Neurotransmitters
– dopamine
– serotonin
– endorphins
Copyright © 1999 by The McGraw-Hill Companies, Inc.
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The Central Nervous System
• Hindbrain
– Medulla
– Cerebellum
– Pons
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The Central Nervous System
• Midbrain
– Reticular Formation
– Basal ganglia
• Forebrain
– Thalamus
– Hypothalamus
Copyright © 1999 by The McGraw-Hill Companies, Inc.
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The Central Nervous System
• Endocrine system
– Hormones
– Pituitary gland
• Limbic system
– Amygdala
– Hippocampus
Copyright © 1999 by The McGraw-Hill Companies, Inc.
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The Central Nervous System
Copyright © 1999 by The McGraw-Hill Companies, Inc.
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The Central Nervous System
• Cerebral Cortex (Cerebrum)
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Occipital lobe
Temporal lobe
Frontal lobe
Parietal lobe
• Association cortex
Copyright © 1999 by The McGraw-Hill Companies, Inc.
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The Central Nervous System
Copyright © 1999 by The McGraw-Hill Companies, Inc.
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Split-Brain Research and the
Cerebral Hemisphere
• Split-brain research
– Corpus Callosum
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Hemispheric specialization
His brain and her brain
Aphasia
Localization and integration of function
– phrenology
Copyright © 1999 by The McGraw-Hill Companies, Inc.
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Brain Damage, Plasticity,
and Repair
• The brain’s plasticity and capacity for repair
– collateral sprouting
– substitution of function
• Brain tissue implants
– the implantation of healthy tissue into damaged
brains
Copyright © 1999 by The McGraw-Hill Companies, Inc.
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Techniques for Studying
the Brain
• Electroencephalograph (EEG)
• Computer-assisted Axial Tomography (CAT
scan)
• Positron-Emission Tomography (PET scan)
• Magnetic Resonance Imaging (MRI)
• Superconducting Quantum Interference
Device (SQUID)
Copyright © 1999 by The McGraw-Hill Companies, Inc.
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