PSY 2012 General Psychology
Chapter 2: Biopsychology
Samuel R. Mathews, Ph.D.
Associate Professor
The Department of Psychology
The University of West Florida
Biological Psychology: Core Concepts
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Evolutionary Perspectives
Individual Genotype and Phenotype
Central Nervous System
Peripheral Nervous System
Endocrine System
How Natural Selection Works
Environmental pressure
(changes in the environment)
Competition
(for resources)
Selection of fittest phenotype
(from among a variety of phenotypes)
Reproductive success
(genotype corresponding to fittest
phenotypes passed to next generation)
Frequency of that genotype increases
(in next generation)
The Individual: Chromosomes, Genes,
and Inherited DNA
• Why are some people shorter than others?
• Why are some babies unable to digest
protein?
• Why are some children born with Down’s
syndrome?
• Why did Sam’s hair fall out?
The Individual: Chromosomes, Genes,
and Inherited DNA
 Chromosomes—
 the structure that carries the genetic material (DNA)
 23 pairs— half contributed by the biological mother
and half by the biological father
• Chromosomes are made up of genes—with
specific DNA codes.
– Each gene is responsible for some characteristic of
the organism and work in concert with others to yield
the whole organism
The Individual: Chromosomes, Genes,
and Inherited DNA
• One pair of chromosomes determines our
biological sex
– The biological mother contributes the X
– The biological father contributes either
another X or a Y chromosome.
• XX= female (more female fetuses survive than
males)
• XY=male
The Individual: Chromosomes, Genes,
and Inherited DNA
• Relationship between genotype and
characteristics and behaviors is complex;
– Inheriting a genotype linked to some
psychopathology does not mean individuals
will experience that pathology (e.g.
schizophrenia).
– Impact of the pathology is frequently
minimized by alterations in the environment
(e.g. corrective lenses).
Hot Issues in Genetics
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Cloning
Choosing the sex of your child
Diagnosis of genetic fetal abnormalities
Choosing your mate
Social engineering
Screening fertilized embryos for markers
of fatal or disabling conditions
The Central Nervous System
The Homer Brain
The Human Brain
Cerebral Cortex: Higher Mental
Functions
Peripheral Nervous System
• Somatic Nervous System—links with senses and
voluntary muscles
• Autonomic Nervous System—links internal glands and
organs
Putting it all together: Puberty
• The experience of puberty is one in which
we can examine the relationship among
species-specific and individual differences,
among the CNS and endocrine system,
and social factors.
• The individual experiences of puberty
reflect the biopsychosocial perspective
• Think back to your own experience with
puberty…how would you describe it?
• How were you prepared?
Puberty Process
• Hypothalamus (part of the brain that controls much of the
endocrine system) Gonadotropin Releasing Hormones
(GRH)Pituitary Gland
• Pituitary gland GonadotropinGonads (ovaries/testes)
• Gonadsstimulate release of sex hormones
(estrogens/androgens) that stimulate secondary sex
characteristics
Puberty Process:
• Process begins approximately 2 years prior to initial
secondary sex characteristic changes;
• Timing of puberty, particularly for females, is related to
timing of maternal puberty but environmental factors also
have a major impact;
• Hypothalamus secretions typically increase during deep
sleep;
• Males and females produce both estrogens and
androgens but in different proportions;
Puberty Process: Physical
Changes
• Secondary sex characteristics
(Phenotype)
– Body/pubic hair (males and females)
– Breast enlargement (most obvious in females)
– Increase in growth rate (females and males)
– Changes in voice (most obvious in males)
– For females, increase in fat to muscle cell
ratio (increase in fat cells relative to muscle
cells)
Puberty Process: Physical Changes
• For females: as level of estrogen increases, the
hypothalamus produces Gonadotropin Inhibiting
Hormones (GIH). This inhibits the production of
estrogen by the ovaries;
• The periodic cycle of increases and decreases
in estrogen controls the ovulation cycle.
• Estrogen is stored in fat cells so the increase in
fat cells relative to muscle cells allows the critical
level of estrogen necessary for ovulation.
Neurological Changes
• Myelinization
– Fatty tissue surrounding nerve cells in the
brain
– Increases the efficiency of transmission of
signals across the synaptic junctions in the
brain
– Made up of cholesterol and proteins
– Rapid increase of myelinization during and
after puberty through adolescence
Neurological Changes
• Elaboration of synaptic connections
– Neurons form new connections based on
experience throughout the lifespan;
– Plasticity still a major force—brain responds
to stimulation
Neurological Changes
• Frontal cortex major area of development
across adolescence
– Maturation of neurological systems that allow:
• Planning
• Regulation of emotion
• Monitoring
– Prediction based on this is that across
adolescence, ability to forecast, anticipate
long-term outcomes and recognize risk is
limited
Health Practices and Puberty Process
• Nutrition—balanced diet including appropriate levels of
carbohydrates (myelinization)
• Sleep—reasonable opportunities for deep sleep
(supports initiation and maintenance of puberty process)
• Limited alcohol consumption—some evidence that
alcohol interferes with hormonal balance of pubescent
females