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Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 5
Chapter 5
The Physical Self
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 5
Chapter 5: The Physical Self
• Genetic and environmental forces
• E.g., height
– Average: female 5’4” male 5’9”
– Can be affected by malnutrition
– Catch-up growth possible
• After illness or periods of malnutrition
– More short people in cold climates
• Smaller body surface for heat loss
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 5
The Endocrine System
Endocrine System
 the body’s “slow”
chemical
communication
system
 a set of glands that
secrete hormones
into the
bloodstream
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 5
Neural and Hormonal Systems
Hormones
 chemical messengers, mostly those
manufactured by the endocrine glands, that
are produced in one tissue and affect
another
Pituitary Gland
 under the influence of the hypothalamus,
the pituitary regulates growth and controls
other endocrine glands
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 5
Neural and Hormonal Systems
Adrenal [ah-DREEN-el] Glands
 a pair of endocrine glands just above the
kidneys
 secrete the hormones epinephrine
(adrenaline) and norepinephrine
(noradrenaline), which help to arouse the
body in times of stress
• Testes secrete androgens like testosterone
• Ovaries secrete estrogen and progesterone
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 5
Figure 3.22 Glands in the endocrine system produce hormones and
release them into the bloodstream. This shows only some of the endocrine
glands and some of their most abundant hormones.
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 5
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 5
Nervous System Cells
Anatomy of a neuron
– Neurons have a variety of shapes, but they all have
3 basic parts.
• A cell body that contains the nucleus and most of
the organelles.
• The dendrites, widely branching structures that
receive transmissions from other neurons.
• The axon, which is a single, long, thin fiber with
branches near its tip.
Action Potential
 a neural impulse; a brief electrical charge that
travels down an axon
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 5
Neural Communication
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Neural Communication
Chapter 5
Synapse [SIN-aps]
 junction between the axon tip of the sending neuron
and the dendrite or cell body of the receiving neuron
 tiny gap at this junction is called the synaptic gap or
cleft
Neurotransmitters
– Communication between neurons occurs at the
synapses.
 chemical messengers that traverse the synaptic
gaps between neurons
 when released by the sending neuron,
neurotransmitters travel across the synapse and
bind to receptor sites on the receiving neuron,
thereby influencing whether it will generate a neural
impulse
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 5
Figure 3.8 The synapse is the junction of the presynaptic (message-sending) cell and
the postsynaptic (message-receiving) cell. At the end of the presynaptic axon is the
terminal bouton (or button), which contains many molecules of the neurotransmitter,
ready for release.
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 5
Figure 5-2
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 5
Plasticity
• Responsiveness to experiences
– Can be negative
• Vulnerable to damage
• Environmental deprivation
– Can be positive
• Aids in recovery from from injury
• Can compensate for each other
• Can benefit from stimulation
• Allows for adaptability
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 5
•
•
Brain Development 2
Critical period: late prenatal & early infancy
Lateralization (at birth)
– Left hemisphere (“thinking side”)
• Sequential processing needed for
analytic reasoning, language
– Right hemisphere (“emotional side”)
• Simultaneous processing needed for
understanding spatial information
• Visual-motor information
• Melody, pitch, sound intensity, affective
content of language
– Corpus callosum connects the two
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 5
Our Divided Brain
Corpus callosum
Corpus Callosum
 large band of
neural fibers
 connects the
two brain
hemispheres
 carries
messages
between the
hemispheres
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 5
Figure 3.26 The corpus callosum is a
large set of axons that convey
information between the two
hemispheres of the cerebral cortex. (a)
A midline view showing the location of
the corpus callosum. (b) A horizontal
section showing how each axon of the
corpus callosum links one spot in the
left hemisphere to a corresponding spot
in the right hemisphere.
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 5
Experience and the brain
The two halves of the brain
– Work with individuals who have had the
“split-brain” operation (severing the corpus
callosum) to control seizures provides
evidence that the two hemispheres are
highly specialized.
– The right hemisphere needs to
communicate with the left in order to name
the objects in its visual field.
– The left hemisphere needs the right in
order to synthesize details into a whole
picture (the parts of a face into a whole
recognizable image).
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 5
Brain Development 3
• Never truly complete
– Changes occur across lifespan
• Growth spurts in infancy, childhood and
adolescence
• Full adult weight by about age 16
• Processing speed increases in adolescence
• Myelination continues into adulthood
Life-Span Human Development, Fifth Edition, Carol K. Sigelman and Elizabeth A. Rider
Chapter 5
Brain Development 4
The Aging Brain
– Gradual and mild degeneration
Elderly adults
– 5-30% fewer neurons than younger adult
– Greater loss in sensory-motor areas
– Plasticity still possible
Main result of age is slower processing