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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