psy i: chapt. 2: lecture (wood)
TRANSCRIPT
mastering the world ofpsychology
CHAPTER
fifth edition
Copyright © 2014, © 2011, © 2008 by Pearson Education, Inc.All Rights Reserved
Biology and Behavior
2
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Learning Objectives
2.1 What does the electroencephalogram (EEG) reveal about the brain?
2.2 How do researchers use imaging techniques to study the nervous system?
2.3 What does each part of the neuron do? 2.4 How do neurons transmit messages through
the nervous system?2.5 How do neurotransmitters work?2.6 What are the structures and functions of the
peripheral nervous system?
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Learning Objectives
2.7 What are the structures and functions of the central nervous system?
2.8 What are the components of the cerebrum?2.9 What are the specialized functions of the left
and right cerebral hemispheres?2.10 Which functions are associated with each of
the four lobes of the cerebral cortex?2.11 How does the brain change across the
lifespan?2.12 How do the brains of men and women differ?
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Learning Objectives
2.13 What are the functions of the glands of the endocrine system?
2.14 How does heredity affect physical and psychological traits?
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Overview
• Discovering the Mysteries of the Nervous System
• The Neurons and the Neurotransmitters • The Human Nervous System • A Closer Look at the Thinking Part of
the Brain • Age, Gender, and the Brain • Beyond the Nervous System
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Discovering the Mysteries of the Nervous System: EEG and Microelectrode
• Electroencephalogram (EEG)– Electrical activity detected by electrodes
placed on the scalp• Microelectrode
– monitors or stimulates activity of a single neuron
LO 2.1
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Discovering the Mysteries of the Nervous System: Imaging Techniques
• CT Scan (Computerized Axial Tomography)– uses a rotating, computerized X-ray
tube – produces cross-sectional images of
brain structures
LO 2.2
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Discovering the Mysteries of the Nervous System: Imaging Techniques
• MRI (Magnetic Resonance Imaging) – produces clearer and more detailed
images without exposure to potentially dangerous X-rays of a CT scan
– can be used to find abnormalities in the central nervous system and in other systems of the body
LO 2.2
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Discovering the Mysteries of the Nervous System: Imaging Techniques
• PET Scan (Positron Emission Tomography)– used to study normal brain activity and
identify malfunctions – maps patterns of blood flow, oxygen
use, and glucose consumption glucose: food of the brain
LO 2.2
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Discovering the Mysteries of the Nervous System: Imaging Techniques
• PET Scan (Positron Emission Tomography)– allows for the study of the action of
drugs and other biochemical substances in the brain and other organs
LO 2.2
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Discovering the Mysteries of the Nervous System: Imaging Techniques
• functional MRI (fMRI)– advantages over PET:
Provides images of both brain structure and brain activity
Requires no injections (of radioactive or other material)
Can identify locations of activity more precisely than PET
LO 2.2
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Discovering the Mysteries of the Nervous System: Imaging Techniques
• functional MRI (fMRI)– advantages over PET:
Detects changes that take place in less than a second, compared with about a minute for PET
• SQUID (Superconducting Quantum Interference Device) – measures magnetic changes produced
by electric current that neurons discharge when they fire
LO 2.2
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Neurons and the Neurotransmitters: The Structure of the Neuron
• Neuron (NEW-ron) – A specialized cell that conducts
impulses through the nervous system• Neurotransmitters
– Specialized chemicals that facilitate or inhibit the transmission of impulses from one neuron to the next
LO 2.3
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Neurons and the Neurotransmitters: The Structure of the Neuron
• Most neurons are made of three parts:– cell body
contains the nucleus carries out the metabolic functions of the
neuron– dendrites
primary receivers of signals from other neurons
LO 2.3
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Neurons and the Neurotransmitters: The Structure of the Neuron
• Most neurons are made of three parts:– axon
slender, tail-like extension of the neuron sprouts into branches, each ending in a
bulbous axon terminal
LO 2.3
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Neurons and the Neurotransmitters: The Structure of the Neuron
• Axon Terminal – Bulbous end of the axon where signals
move from the axon of one neuron to the dendrites or cell body of another
LO 2.3
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Neurons and the Neurotransmitters: The Structure of the Neuron
• Glial Cells – located in the brain and spinal cord– support neurons, remove waste
products– perform other manufacturing,
nourishing, and cleanup tasks
LO 2.3
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Figure 2.1 The Structure of a Typical NeuronA typical neuron has three important parts: (1) a cell body, which carries out the metabolic functions of the neuron; (2) branched fibers called dendrites, which are the primary receivers of the impulses from other neurons; and (3) a slender, tail-like extension called an axon, the transmitting end of the neuron, which sprouts into many branches, each ending in an axon terminal. The photograph shows human neurons greatly magnified.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Neurons and the Neurotransmitters: Communication between Neurons
• Axon terminals are separated from the receiving neurons by fluid-filled gaps: synaptic clefts.
• Synapse – junction where axon terminal of sending
neuron communicates with receiving neuron
LO 2.4
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Neurons and the Neurotransmitters: Communication between Neurons
• Synapse – There may be as many as 100 trillion
synapses in the human nervous system.– A single neuron may form synapses with
thousands of other neurons.
LO 2.4
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The Neurons and the Neurotransmitters: Communication between Neurons
• A measurable electrical impulse is present with every move or thought.
• Permeability of cell membrane changes– allows ions to move into and out of the
axon
LO 2.4
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The Neurons and the Neurotransmitters: Communication between Neurons
• Body fluids contain ions.– Ions have positive or negative electrical
charges.– There are normally more negative than
positive ions.– An axon at rest carries about 70
millivolts (relative to the fluid outside the cell).
LO 2.4
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Figure 2.2 The Action PotentialThe action potential moves down the axon to the axon terminals.Source: Adapted from Lilienfeld, Lynn, Namy, & Wolf (2009).
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Neurons and the Neurotransmitters: Communication between Neurons
• Resting Potential– slight negative electrical potential of the
axon membrane of a neuron at rest• Action Potential
– sudden reversal of the resting potential, initiates firing of neuron
LO 2.4
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Neurons and the Neurotransmitters: Communication between Neurons
• "All or None" Law– A neuron either fires completely or does
not fire at all.• Refractory Period
– short resting period after firing during which a neuron cannot fire again
LO 2.4
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The Neurons and the Neurotransmitters: Communication between Neurons
• Myelin Sheath– white, fatty coating on some axons– makes action potential travel up to 100
times faster• Nodes of Ranvier
– gaps in the myelin sheath– Neural impulse is regenerated at each
node
LO 2.4
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Neurons and the Neurotransmitters: Communication between Neurons
• Receptors – Protein molecules on the surfaces of
dendrites and cell bodies that have distinctive shapes and will interact only with specific neurotransmitters
LO 2.4
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The Neurons and the Neurotransmitters: Neurotransmitters
• Neurotransmitters – chemical substances that transmit
messages between neurons– released into synapse by axon terminals
of sending neuron– bind to receptor sites on dendrites of
receiving neuron– taken back into axon terminal by the
process of reuptake
LO 2.5
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Figure 2.3 Synaptic TransmissionSending neurons transmit their messages to receiving neurons by electrochemical action. When a neuron fires, the action potential arrives at the axon terminal and triggers the release of neurotransmitters from the synaptic vesicles. Neurotransmitters flow into the synaptic cleft and move toward the receiving neuron, which has numerous receptors. The receptors will bind only with neurotransmitters whose molecular shapes match their enclosed volumes. Neurotransmitters influence the receiving neuron to fire or not to fire.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Neurons and the Neurotransmitters: Neurotransmitters
• How do synaptic vesicles continue to pour out neurotransmitters yet maintain a ready supply of neurotransmitter?– The cell body of the neuron is always
working to manufacture more of the neurotransmitter.
LO 2.5
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Neurons and the Neurotransmitters: Neurotransmitters
• How do synaptic vesicles continue to pour out neurotransmitters yet maintain a ready supply of neurotransmitter?– Unused neurotransmitters in the
synaptic cleft may be broken down into components and reclaimed by the axon terminal to be recycled.
LO 2.5
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Neurons and the Neurotransmitters: Neurotransmitters
• How do synaptic vesicles continue to pour out neurotransmitters yet maintain a ready supply of neurotransmitter?– Reuptake: the neurotransmitter is taken
back into the axon terminal, intact and ready for immediate use.
LO 2.5
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Table 2.1 Major Neurotransmitters and Their Functions
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Figure 2.4 The HumanNervous System The nervous system is divided into two parts: the peripheral nervous system and the central nervous system. The diagram shows the relationships among the parts of the nervous system and provides a brief description of the functions of those parts.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Human Nervous System:The Peripheral Nervous System
• The peripheral nervous system consists of two subdivisions.– somatic nervous system
consists of all sensory nerves and motor nerves
– autonomic nervous system transmits messages between the central
nervous system and glands, cardiac muscle, and smooth muscles
LO 2.6
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Human Nervous System:The Peripheral Nervous System
• Sympathetic Nervous System– mobilizes the body's resources during
stress and emergencies• Parasympathetic Nervous System
– brings heightened bodily responses back to normal following an emergency
LO 2.6
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Figure 2.5 The Autonomic Nervous SystemThe autonomic nervous system consists of (1) the sympathetic nervous system, which mobilizes the body’s resources during emergencies or stress, and (2) the parasympathetic nervous system, which brings the heightened bodily responses back to normal afterward. This diagram shows the opposite effects of the sympathetic and parasympathetic nervous systems on various parts of the human body.Source: Lilienfeld, Lynn, Namy, & Woolf (2009).
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Human Nervous System:The Central Nervous System
• Spinal Cord– best thought of as extension of the
brain– transmits messages between the brain
and the peripheral nervous system– can act without help from the brain to
protect the body from injury
LO 2.7
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The Human Nervous System:The Central Nervous System
• Spinal Cord– Withdrawal or Spinal Reflex
triggered by a painful stimulus involves 3 types of neurons:
– sensory-afferent– motor-efferent– interneuron
LO 2.7
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Figure 2.6 The Spinal ReflexThe sequence that begins with a sensory stimulus (such as touching something hot) and ends with a behavioral response (withdrawing the hand) involves sensory neurons, interneurons, and motor neurons.Source: Adapted from Lilienfeld, S., Lynn, S., Namy, L., & Woolf, N. (2009).
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Figure 2.7 Major Structures of the Human BrainThis drawing shows some of the major structures of the brain with a brief description of the function of each. The brainstem contains the medulla, the reticular formation, and the pons.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Human Nervous System:The Hindbrain
• Structures control vital functions.• Brainstem
– begins at the site where the spinal cord enlarges as it enters the skull
LO 2.7
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Human Nervous System:The Hindbrain
• Hindbrain – a link between the spinal cord and the
brain that contains structures that regulate physiological functions, including heart rate, respiration, and blood pressure
LO 2.7
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The Human Nervous System:The Hindbrain
• Medulla– controls heartbeat, blood pressure,
breathing, coughing, swallowing• Reticular Formation
– plays a crucial role in arousal and attention
– screens sensory messages entering the brain
LO 2.7
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The Human Nervous System:The Hindbrain
• Pons– plays a role in body movement– influences sleep and dreaming
• Reticular formation– a structure in the brainstem that plays a
crucial role in arousal and attention and that screens sensory messages entering the brain
LO 2.7
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The Human Nervous System:The Hindbrain
• Cerebellum– helps the body execute smooth, skilled
movements– regulates muscle tone and posture
LO 2.7
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The Human Nervous System:The Midbrain
• The midbrain links the physiological functions of the hindbrain to the cognitive functions of the forebrain.
• Substantia Nigra– controls unconscious motor movements
LO 2.7
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The Human Nervous System:The Forebrain
• Forebrain – largest part of the brain– functions include memory, logic, and
self-awareness• Thalamus
– relay station for information flowing into or out of the brain
LO 2.7
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Human Nervous System:The Forebrain
• Hypothalamus– regulates hunger, thirst, sexual
behavior, body temperature, and a variety of emotional behaviors
LO 2.7
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Human Nervous System:The Forebrain
• Limbic system – a group of structures in the brain,
including the amygdala and hippocampus, that are collectively involved in emotional expression, memory, and motivation
LO 2.7
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Figure 2.8 The Principal Structures in the Limbic SystemThe amygdala plays an important role in emotion; the hippocampus is essential in the formation of new memories.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
The Human Nervous System:The Forebrain
• Amygdala– part of the limbic system – plays important role in emotion
• Hippocampus– part of the limbic system– central role in storing new memories,
responses to new or unexpected stimuli, and navigational ability
LO 2.7
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Figure 2.9 Two Views of the Cerebral Hemispheres(a) The two hemispheres rest side by side like two matched halves, physically connected by the corpus callosum. (b) An inside view of the right hemisphere.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
A Closer Look at the Thinking Part of the Brain: Components of the Cerebrum
• Cerebral Hemispheres– left and right halves of cerebrum
• Corpus Callosum– connects the two hemispheres
• Cerebral Cortex– thin outer covering of cerebrum– responsible for higher mental processes
of language, memory, and thinking
LO 2.8
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
A Closer Look at the Thinking Part of the Brain: Components of the Cerebrum
• The cerebral cortex contains 3 types of areas. – Sensory Input Areas
vision, hearing, touch, pressure, and temperature register
– Motor Areas control voluntary movement
LO 2.8
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A Closer Look at the Thinking Part of the Brain: Components of the Cerebrum
• The cerebral cortex contains 3 types of areas. – Association Areas
house memories and are involved in thought, perception, and language
LO 2.8
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A Closer Look at the Thinking Part of the Brain: The Cerebral Hemispheres
• Lateralization – the specialization of one of the cerebral
hemispheres to handle a particular function
• Left Hemisphere– controls the right side of the body– handles most language functions– specialized for mathematics and logic
LO 2.9
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A Closer Look at the Thinking Part of the Brain: The Cerebral Hemispheres
• Right Hemisphere– controls left side of body– processes music– interprets emotional messages
conveyed by tone of voice and gestures– is specialized for visual-spatial relations
LO 2.9
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Figure 2.10 Lateralized Functions of the BrainAssigning functions to one hemisphere or the other allows the brain to function more efficiently.Source: Based on Gazzaniga (1983).
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A Closer Look at the Thinking Part of the Brain: The Split Brain
• Corpus callosum is absent or has been surgically modified.
• Only the verbal left hemisphere can report what it sees.
• The left hemisphere does not see what is flashed to the right hemisphere; the right hemisphere is unable to report verbally what it has viewed.
LO 2.9
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Figure 2.11 Testing a Split-Brain PersonUsing special equipment, researchers are able to study the independent functioning of the hemispheres in split-brain patients. In this experiment, when a visual image (an orange) is flashed on the right side of the screen, it is transmitted to the left (talking) hemisphere. When asked what he sees, the split-brain patient replies, “I see an orange.” When an image (an apple) is flashed on the left side of the screen, it is transmitted only to the right (nonverbal) hemisphere. Because the split-brain patient’s left (language) hemisphere did not receive the image, he replies, “I see nothing.” But he can pick out the apple by touch if he uses his left hand, proving that the right hemisphere “saw” the apple.Source: Based on Gazzaniga, M. (1983).
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Figure 2.12 The Four Lobes of the Cerebral CortexThis illustration of the left cerebral hemisphere shows the four lobes: (1) the frontal lobe, including the motor cortex and Broca’s area; (2) the parietal lobe, with the somatosensory cortex; (3) the occipital lobe, with the primary visual cortex; and (4) the temporal lobe, with the primary auditory cortex and Wernicke’s area.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
A Closer Look at the Thinking Part of the Brain: The Four Cerebral Lobes
• Frontal Lobes• Prefrontal Cortex
– The part of the frontal lobes directly behind the forehead that controls executive processing, the coordination of multiple brain activities in pursuit of cognitive goals
• Motor Cortex– controls voluntary body movement
LO 2.10
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
A Closer Look at the Thinking Part of the Brain: The Four Cerebral Lobes
• Broca's Area– located in frontal lobe– usually in the left hemisphere– controls speech production
• Aphasia (uh-FAY-zyah) – a loss or impairment of the ability to use
or understand language, resulting from damage to the brain
LO 2.10
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A Closer Look at the Thinking Part of the Brain: The Four Cerebral Lobes
• Association Areas– areas involved in thinking, planning for
the future, impulse control
LO 2.10
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
A Closer Look at the Thinking Part of the Brain: The Four Cerebral Lobes
• Parietal Lobes– somatosensory cortex
located at the front of the parietal lobes where touch, pressure, temperature, and
pain register in the cortex
LO 2.10
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
A Closer Look at the Thinking Part of the Brain: The Four Cerebral Lobes
• Occipital Lobes– involved in reception and interpretation
of visual information• Primary Visual Cortex
– area at the rear of the occipital lobes where vision registers in the cortex
LO 2.10
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
A Closer Look at the Thinking Part of the Brain: The Four Cerebral Lobes
• Temporal Lobes• Primary Auditory Cortex
– area in each temporal lobe where hearing registers in the cortex
• Wernicke's Area– language area in the left temporal lobe
involved in comprehending spoken language and formulating coherent speech and written language
LO 2.10
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Age Gender and the Brain:The Ever-Changing Brain
• The brain grows in spurts from conception until well into adulthood.
• Each growth spurt also seems to involve a different brain area.– The spurt that begins around age 17
and continues into the early 20s mainly affects the frontal lobes
Age, Gender, and the Brain:The Ever-Changing Brain
LO 2.11
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Age, Gender, and the Brain:The Ever-Changing Brain
• Synaptogenesis– occurs in spurts throughout the life span
• Pruning– process through which the developing
brain eliminates unnecessary or redundant synapses follows periods of synaptogenesis
LO 2.11
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Age, Gender, and the Brain:The Ever-Changing Brain
• Stroke – an event in the cardiovascular system in
which a blood clot or plug of fat blocks an artery and cuts off the blood supply to a particular area of the brain
• Myelination– development of myelin sheaths around
axons
LO 2.11
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Age, Gender, and the Brain:The Ever-Changing Brain
• Myelination– begins prior to birth but continues well
into adulthood• Plasticity
– the capacity to adapt to changes is maintained throughout life
LO 2.11
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Age Gender and the Brain: Gender Differences in the Brain
• Women's Brains– Equal proportions of gray and white
matter in the left and right hemispheres– More gray matter in the area of the
brain that controls emotions may explain women's superior ability to
perceive emotions
Age, Gender, and the Brain: Gender Differences in the Brain
LO 2.12
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Age, Gender, and the Brain: Gender Differences in the Brain
• Women's Brains– Navigational Information
use right parietal cortex and right frontal cortex
LO 2.12
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Age, Gender, and the Brain: Gender Differences in the Brain
• Men's Brains– Lower proportion of white matter in the
left hemisphere than in the right may explain men's superior ability in
spatial tasks– Navigational Information
use left hippocampus
LO 2.12
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Figure 2.13 The Endocrine SystemThe endocrine system is a series of glands that manufacture and secrete hormones. The hormones travel through the circulatory system and have important effects on many bodily functions.
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Beyond the Nervous System:The Endocrine System
• Endocrine System (EN-duh-krin)– system of ductless glands
manufacture hormones secretes hormones into bloodstream
– hormone chemical substance that is manufactured
and released in one part of the body and affects other parts of the body
LO 2.13
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Beyond the Nervous System:The Endocrine System
• Endocrine Glands– pituitary gland
"master gland" releases hormones that activate other
endocrine glands– pineal gland
secretes melatonin, which controls sleep/wakefulness cycle
LO 2.13
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Beyond the Nervous System:The Endocrine System
• Thyroid Gland– located below the voice box – produces thyroxine
regulates rate of food metabolization• Parathyroid Gland
– produces parathyroid hormone helps the body absorb minerals from the
diet
LO 2.13
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Beyond the Nervous System:The Endocrine System
• Thymus Gland– produces thymosin– regulates immune system
LO 2.13
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Beyond the Nervous System:The Endocrine System
• Adrenal Gland– releases hormones that prepare the
body for emergencies and stressful situations
• Pancreas – the endocrine gland responsible for
regulating the amount of sugar in the bloodstream
LO 2.13
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Beyond the Nervous System:The Endocrine System
• Gonads– ovaries in females– testes in males– produce sex hormones
LO 2.13
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Beyond the Nervous System: Genes and Behavioral Genetics
• Genes– segments of DNA located on
chromosomes – transmit all heredity traits
• Chromosomes– 46 chromosomes (23 pairs) contain
20,000 to 25,000 genes– 22 matching pairs called autosomes;
23rd pair are sex chromosomes
LO 2.14
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Beyond the Nervous System: Genes and Behavioral Genetics
• Genotype – An individual's genetic makeup
• Phenotype – An individual's actual characteristics
LO 2.14
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Beyond the Nervous System: Genes and Behavioral Genetics
• Dominant-Recessive Pattern– dominant
It is only necessary that one gene be present on chromosome pair for a given trait to be expressed.
– recessive Two genes are required on the
chromosome pair for trait expression.
LO 2.14
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Beyond the Nervous System: Genes and Behavioral Genetics
• Polygenetic Inheritance– Many genes influence a particular
characteristic.• Multifactorial inheritance
influenced by genes and environmental factors
LO 2.14
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Beyond the Nervous System: Genes and Behavioral Genetics
• Sex-Linked Inheritance– involves genes on the X and Y
chromosomes example: red-green color blindness
LO 2.14
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Beyond the Nervous System: Genes and Behavioral Genetics
• Behavioral Genetics– investigates the effects of heredity and
environment on behavior• Twin Studies
– examine identical (monozygotic) and fraternal (dizygotic) twins in order to compare similarities and differences in twin pairs
LO 2.14
Mastering the World of Psychology, Fifth EditionSamuel Wood | Ellen Green Wood | Denise Boyd
Beyond the Nervous System: Genes and Behavioral Genetics
• Adoption Studies– compare adopted children's abilities and
traits to those of adoptive parents and biological parents
LO 2.14