chapter 2 biological foundations and the brain. copyright © 1999 by the mcgraw-hill companies, inc....

Chapter 2

Biological Foundationsand the Brain

Copyright © 1999 by The McGraw-Hill Companies, Inc. 2

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

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Perspectives on Natureand 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

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Perspectives on Natureand 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

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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

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The Nervous System

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The Nervous System

• Neurons• Central Nervous System (CNS)• Peripheral nervous system• Somatic nervous system• Autonomic nervous system

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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

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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

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Structure of the Neuron

• Cell body• Dendrite• Axon• Myelin sheath

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The Nerve Impulse

• Ions• Resting potential• Action Potential• All-or-none principle

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Synapses and Neurotransmitters

• Synapses• Neurotransmitters

– dopamine– serotonin– endorphins

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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

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The Central Nervous System

• Endocrine system– Hormones– Pituitary gland

• Limbic system– Amygdala– Hippocampus

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The Central Nervous System

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The Central Nervous System

• Cerebral Cortex (Cerebrum)– Occipital lobe– Temporal lobe– Frontal lobe– Parietal lobe

• Association cortex

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The Central Nervous System

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Split-Brain Research and theCerebral Hemisphere

• Split-brain research– Corpus Callosum

• Hemispheric specialization• His brain and her brain• Aphasia• Localization and integration of function

– phrenology

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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

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Techniques for Studyingthe Brain

• Electroencephalograph (EEG)• Computer-assisted Axial Tomography

(CAT scan)• Positron-Emission Tomography (PET scan)• Magnetic Resonance Imaging (MRI)• Superconducting Quantum Interference

Device (SQUID)