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 Electrical activity detected by electrodes placed on the scalp  Produces record of brain-wave activity beta wave: pattern associated with mental or physical activity alpha wave: associated with deep relaxation delta wave: slow-wave (deep) sleep  Shows epileptic seizure in progress, neural activity of other disorders  Microelectrode monitors or stimulates activity of a single neuron Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 CT Scan (Computerized Axial Tomography) uses a rotating, computerized X-ray tube produces cross-sectional images of brain structures  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 Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 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 allows for the study of the action of drugs and other biochemical substances in the brain and other organs Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 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  Detects changes that take place in less than a second, compared with about a minute for PET Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 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 axon  slender, tail-like extension of the neuron  sprouts into branches, each ending in a bulbous axon terminal Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 Glial Cells located in the brain and spinal cord support neurons, remove waste products perform other manufacturing, nourishing, and cleanup tasks Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 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 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. Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 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  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). Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 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  “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 Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 Influenced by the 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.

Copyright © 2011 Pearson Education, Inc. All Rights Reserved  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

The cell body of the neuron is always working to manufacture more of the neurotransmitter. Unused neurotransmitters in the synaptic cleft may be broken down into components and reclaimed by the axon terminal to be recycled. Reuptake: the neurotransmitter is taken back into the axon terminal, intact and ready for immediate use. Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 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 Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 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 Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 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 Copyright © 2011 Pearson Education, Inc. All Rights Reserved

Withdrawal or Spinal Reflex  triggered by a painful stimulus  involves 3 types of neurons:  sensory-afferent  motor-efferent  interneuron Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 Structures control vital functions.  Brainstem begins at the site where the spinal cord enlarges as it enters the skull  Medulla controls heartbeat, blood pressure, breathing, coughing, swallowing  Reticular Formation plays a crucial role in arousal and attention screens sensory messages entering the brain (relay pathway)

Copyright © 2011 Pearson Education, Inc. All Rights Reserved  Pons plays a role in body movement influences sleep and dreaming  Cerebellum helps the body execute smooth, skilled movements regulates muscle tone and posture

Copyright © 2011 Pearson Education, Inc. All Rights Reserved  The midbrain links the physiological functions of the hindbrain to the cognitive functions of the forebrain.  Substantia Nigra controls unconscious motor movements

Copyright © 2011 Pearson Education, Inc. All Rights Reserved  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  Hypothalamus regulates hunger, thirst, sexual behavior, body temperature, and a variety of emotional behaviors

Copyright © 2011 Pearson Education, Inc. All Rights Reserved  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

Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 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

 The cerebral cortex contains 3 types of areas. Sensory Input Areas  vision, hearing, touch, pressure, and temperature register Motor Areas  control voluntary movement Association Areas  house memories and are involved in thought, perception, and language Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 Left Hemisphere controls the right side of the body handles most language functions specialized for mathematics and logic Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 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 Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 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. Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 Frontal Lobes  Motor Cortex controls voluntary body movement  Broca’s Area located in frontal lobe usually in the left hemisphere controls speech production  Association Areas areas involved in thinking, planning for the future, impulse control Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 Parietal Lobes somatosensory cortex  located at the front of the parietal lobes  where touch, pressure, temperature, and pain register in the cortex Copyright © 2011 Pearson Education, Inc. All Rights Reserved A Closer Look at the Thinking Part of the Brain: A Closer Look at the Thinking Part of the Brain: The Four Cerebral Lobes

Copyright © 2011 Pearson Education, Inc. All Rights Reserved  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

 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 Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 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.  Synaptogenesis occurs in spurts throughout the life span  Pruning process through which the developing brain eliminates unnecessary or redundant synapses follows periods of synaptogenesis  Myelination development of myelin sheaths around axons begins prior to birth but continues well into adulthood  Plasticity The capacity to adapt to changes is maintained throughout life. Copyright © 2011 Pearson Education, Inc. All Rights Reserved

WOMEN’S BRAINSMEN’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  Navigational Information use right parietal cortex and right frontal cortex  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 Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 System of Ductless Glands manufacture hormones secretes hormones into bloodstream  Endocrine Glands pituitary gland  “master gland”  releases hormones that activate other endocrine glands pineal gland  secretes melatonin, which controls sleep/wakefulness cycle Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 Thyroid Gland located below the voice box produces thyroxine  regulates rate of food metabolization  Thymus Gland produces thymosin regulates immune system  Parathyroid Gland produces parathyroid hormone  helps the body absorb minerals from the diet Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 Thymus Gland produces hormones essential to immune system functioning  Adrenal Gland releases hormones that prepare the body for emergencies and stressful situations  Gonads ovaries in females testes in males produce sex hormones Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 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; 23 rd pair are sex chromosomes  Polygenetic Inheritance Many genes influence a particular characteristic. multifactorial inheritance  influenced by genes and environmental factors Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 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.  Sex-Linked Inheritance involves genes on the X and Y chromosomes  example: red-green color blindness Copyright © 2011 Pearson Education, Inc. All Rights Reserved

 Behavioral Genetics investigates the effects of heredity and environment on behavior  Twin Studies examine identical (monozygotic) and fraternal (dizygotic) twins  compare similarities and differences in twin pairs  Adoption Studies compare adopted children’s abilities and traits to those of adoptive parents and biological parents Copyright © 2011 Pearson Education, Inc. All Rights Reserved