Introduction to Psychology - Chapter 2 PDF

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Detailed notes for chapter 2, covered in the 3rd week of class. These were very useful on tests and I finished the class with an A....

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Fall 2018 – September 5th and September 10th Textbook: Invitation to Psychology 7th Edition (2017) by Wade, C., Tavris, C., Sommers S., & Shin, L. Chapter 2: Neurons, Hormones, and The Brain • Neuroscientists- study the nervous system in hopes of gathering a better understanding of normal behavior and outer reaches of what is possible for this organ • Cognitive neuroscientists- explore the biological foundations of consciousness, perception, memory, and language • Social neurologist- focus on the brain basis of processes such as social interactions, empathy, and prejudice • Affective neurologists- study the nervous system’s involvement in emotion, motivation, and stress • Behavioral neurologists- study the biology of basic processes such as learning, conditioning, eating, and sex • Self-awareness makes brain research different from the study of anything else

Section 2.1 The Central Nervous System: • Central Nervous System (CNS)- the portion of the nervous system consisting of the brain and spinal cord o Receives, processes, interprets, and stores incoming sensory information (information about tastes, sounds, smells, colors, pressure on the skin, state of internal organs, etc. o Spinal cord- a collection of neurons and supportive tissue running from the base of the brain down the center of the back, protected by a column of bones (the spinal column) o Spinal reflexes- automatic behaviors requiring no help from the brain or conscious effort, example: pulling your hand away from a hot pan The Peripheral Nervous System • Peripheral Nervous System (PNS)- all portions of the nervous system outside of the brain and spinal cord, including sensory and motor nerves o Handles the central nervous system’s input and output o Sensory nerves- carry messages from special receptors in the skin, muscles, and other internal and external sense organs to the spinal cord, which sends them to the brain

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§ Put us in touch with the outside world and the activities of our bodies o Motor nerves- carry orders from the central nervous system to muscles, glands, and internal organs § Enable us to move, cause glands to contract and secrete substances, including chemical messengers called hormones The Peripheral Nervous System is divided into two parts: 1. Somatic Nervous System (Skeletal Nervous System)- connects to sensory receptors and to skeletal muscles a. Enables you to sense the world and permits voluntary action 2. Autonomic Nervous System- regulates the internal organs and glands a. Regulates functioning of blood vessels, glands, and internal organs like the bladder, stomach, and heart b. Example: When you see someone you’ve fallen for, your heart pounds, your hands get sweaty, or your face feels flushed c. The autonomic nervous system is divided into two parts: • Sympathetic Nervous System- mobilizes bodily resources and increases the output of energy during emotion and stress a. Makes you blush, sweat, breathe deeply, increases heartrate or blood pressure b. When in a situation that requires fight, flee, or cope • Parasympathetic Nervous System- operates during relaxed states and conserves energy a. Slows thinks down and keeps them running smoothly b. Example: After heartrate is increases, it slows it back down and keeps it regular • The sympathetic nervous system prepares the body to expend energy and the parasympathetic nervous system restores and conserves energy

Section 2.2 Types of Cells: • Neurons- cell that conducts electrochemical signals; the basic unit of the nervous system; also called a nerve cell o The brain’s communication specialist, transmit information to, from, and within the central nervous system • Glia (glial cells)- cells that support, nurture, and insulate neurons, remove debris when neurons die, enhance the formation and maintenance of neural connections, and modify neuronal functioning o From the Greek word for “glue” o They hold the neurons in place, provide them with nutrients, insulate them, help them grow, protect the brain from toxic agents, and remove cellular debris o Also communicate chemically with each other and with neurons o Without them, neurons couldn’t function effectively The Structure of the Neuron: • The neuron has three main parts: 1. Dendrites- a neuron’s branches that receive information from other neurons and transmit it toward the cell body 2. Cell body- the part of the neuron that keeps it alive and determines whether or not it will fire 3. Axon- a neuron’s extending fiber that conducts impulses away from the cell body, transmitting them to other neurons • Dendrites look like tree branches (means “little tree” in Greek) and act like antennas, receiving messages and transmitting them to the cell body • The cell body is shaped like a sphere or pyramid and includes the cell’s nucleus and the rest of the biochemical machinery that keeps the neuron alive and produces neurochemicals • The axon (Greek for “axle”) is attached to the cell body and transmits messages away from the cell body to other neurons or muscles and gland cells o Commonly divide at the end into axon terminals o Many axons are insulated by a surrounding layer of fatty material called the myelin sheath § Constrictions on this covering, called nodes, divide into segments § The purpose of the myelin sheath is to prevent signals from adjacent cells from interfering with each other § Another is to speed up the conduction of neural impulses

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Multiple sclerosis- loss of myelin causes erratic nerve signals, leading to loss of sensation, weakness or paralysis, lack of coordination or vision problems In the peripheral nervous system, fibers of individual neurons (axons and sometimes dendrites) are collected together in bundles called nerves o Nerves- a bundle of fibers in the peripheral nervous system o The human body has 43 pairs of nerves o Most leave the spine, but 12 pairs in the head called cranial nerves connect directly to the brain

The Birth of Neurons: • Neurogenesis- the production of new neurons from immature stem cells • Stem cells- immature cells that renew themselves and have the potential to develop into mature cells; given encouraging environments, then cay develop into any cell type o Can be useful for treating damaged tissues How Neurons Communicate: • Neurons are separated by a miniscule space called the synaptic cleft • Synapse- the site where transmission of a nerve impulse from one nerve cell to another occurs; it includes the axon terminal, synapse cleft, and receptor sites in the membrane of the receiving cell • Neurons communicate through electrical and chemical language • They contain ions, at rest they are negatively charged but when stimulated, special “gates” allow positive Na ions inside, making it less negative • Action potential- a brief change in electrical voltage that occurs between the inside and outside of an axon when a neuron is stimulated, producing an electrical impulse o As a result, the neuron “fires” and positive K ions quickly move outside, restoring negativity o If an axon is unmylelinated, this process repeats down the axon like dominoes o In myelinated axons, the action potential “hops’ from one node to the next • Neurotransmitters- a chemical substance released by a transmitting neuron as the synapse, altering activity of the receiving neuron o Synaptic vesicles- sacs in an axon terminal that release neurotransmitters o Neurotransmitters bind briefly with receptor sites, then they may be returned to the releasing cell in a process called reuptake o Some neurotransmitters cause a decrease in negative charge and when the charge reaches a critical level, the neuron fires—the excitatory effect o Other neurotransmitters cause an increase in negative charge, making it less likely to fire—inhibitory effect

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Inhibition is essential and without it we couldn’t sleep or coordinate our movements

Versatile Carriers: • Four neurotransmitters travel in a particular path through parts of the brain: 1. Serotonin- affects neuron involved in sleep, appetite, sensory perception, temperature regulation, pain suppression, and mood 2. Dopamine- affects neurons involved with voluntary movement, attention, learning, memory, emotion, pleasure and reward, and possible responses to novelty 3. Acetylcholine- affects neurons involved with muscle action, arousal, vigilance, memory, and emotion 4. Norepinephrine- affects neurons involved in the increased heartrate and the slowing of intestinal activity during stress, and neurons involved in learning, memory, dreaming, waking from sleep, and emotion • Two other common neurotransmitters: o GABA (gamma aminobutyric acid)- the major inhibitory neurotransmitter o Glutamate- the major excitatory neurotransmitter, released by 90% of the brain’s neurons Hormones: • Hormones- chemical substances, secreted by organs called glands, that affect the functioning of other organs • Endocrine glands- internal organs that produce hormones and release them into the bloodstream o Pancreas, ovaries, testes, and adrenal glands • Hormones have dozens of jobs, some examples are: promoting bodily growth, aiding in digestion, and regulating metabolism • Neurotransmitters and hormones aren’t always chemically distinct because some substances have more than one role, for example: norepinephrine can be either depending on where it is and what function it’s performing • Hormones of particular interest to psychologists: 1. Melatonin- secreted by the pineal gland deep in the brain, helps to regulate daily biological rhythms and promotes sleep 2. Oxytocin- secreted by the pituitary gland in the brain, enhances uterine contractions during childbirth and facilitates the ejection of milk during nursing; along with vasopressin, it contributes to relationships by promoting social attachment 3. Adrenal hormones- hormones produced by adrenal glands involved in emotion and stress, and respond to heat, cold, pain, injury, and physical exercise, as well as caffeine and nicotine

a. Cortisol- increases blood sugar levels and boosts energy b. Epinephrine (adrenaline) and norepinephrine- adrenal hormones increase arousal level and prepare you for action, they can also enhance memory 4. Sex hormones- regulate development and functioning of reproductive organs and stimulate the development of sexual characteristics a. Androgens (including testosterone)- masculinizing hormones that causes deepens voice, facial, chest, pubic, and underarm and influences arousal b. Estrogen- feminizing hormones that cause breast development and menstruation c. Progesterone- contributes to the growth and maintenance of uterine lining in preparation of a fertilized egg, among other functions Neuromodulators: • Neuromodulators- neurochemicals that vary the strength of the functioning of neurons and neurotransmitters • Endorphins- chemical substances in the nervous system that are involved in pain reduction, pleasure, and memory, and are known technically as endogenous opioid peptides o Effects similar to heroin—reduces pain and promotes pleasure o Endorphin levels shoot up when afraid or under stress o A link also exists between endorphins and human attatchment

Section 2.3 Manipulating the Brain and Observing Behavior: • Lesion method- the removal or disabling of a brain structure to gain better understanding of its function (only used in nonhuman animals) • Transcranial Magnetic Stimulation (TMS)- method of manipulating brain cells using a powerful magnetic field produced by a wire coil placed on a person’s head; can be used to temporarily stimulate or inactivate neural circuits • Transcranial Direct Current Stimulation (tDCS)- a technique that applies a very small electric current to stimulate or suppress activity in parts of the cortex; enables researching to identify the functions of a particular brain region Manipulating Behavior and Observing the Brain: • Electroencephalogram (EEG)- a recording of neural activity detected by electrodes o Electrodes- devices glued or taped onto the scalp to detect the simultaneous electrical activity of millions of neurons in particular brain regions • Event-Related Potentials (ERP)- technique that isolates the neural activity associated with a specific stimulus (“event”) • PET Scan (position-emission tomography)- a method for analyzing biochemical activity in the brain, for example: by using injections of a glucose-like substance containing a radioactive element o The areas which consume the glucose emit radiation • MRI (magnetic resonance imaging)- method for studying body and brain tissue using magnetic fields and special radio receivers to take highly detailed pictures of the brain o Structural MRI- shows what the brain looks like but not what it does o Functional MRI (fMRI)- type of MRI used to study brain activity associated with specific thoughts and behaviors Controversial Cautions: • Technology cannot replace critical thinking • Images cannot convey oversimplified and sometimes misleading impressions

Section 2.4 The Brain Stem and Cerebellum: • Brain stem- part of the brain at the top of the spinal cord, consisting of the medulla and the pons o Medulla- a structure in the brain stem responsible for certain automatic functions, such as breathing and heartrate o Pons- a structure in the brain stem involved in sleeping, waking, and dreaming, among other things • Reticular Activating System (RAS)- a dense network of neurons found in the core of the brain stem that arouses the cortex and screens incoming information • Cerebellum- brain structure that regulates movement and balance, is involved in classical conditioning and remembering simple skills, and plays a role in perceptual and some higher-level cognitive processes The Thalamus: • Deep in the brain’s interior, roughly in the center, lies the thalamus • Thalamus- brain structure that relays sensory messages to the cerebral cortex • Directs sensory images of sight, sound, and touch to higher areas in charge; the only sense it bypasses is smell o Olfactory bulb- processes smell and lies near areas involved in emotion Hypothalamus and Pituitary Gland: • Under the thalamus lies the hypothalamus (hypo means “under”) • Hypothalamus- brain structure involved in emotions and drives that are vital to survival; regulates the autonomic nervous system • Constantly monitors the body's state and issues instructions to help maintain homeostasis • Associated with the “four F’s”—feeding, fighting, fleeing, and fucking • Regulates body temperature and controls the body’s daily rhythms • Below the hypothalamus, connected by a short stalk, is the pituitary gland • Pituitary gland- small endocrine gland at the base of the brain that releases hormones and regulates other endocrine glands • Called the body’s “master gland” The Amygdala: • Amygdala- brain structure involved in assessing the potential biological impact of incoming sensory information and driving the body’s response to it • From the Greek word for “almond” • Located deep within the brain, underneath the temples

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Contributes to the fight or flight decision, the brain’s “fear center” Plays a role in regulating anxiety and depression and forming and retrieving emotional memories

The Hippocampus: • Immediately behind the amygdala is the hippocampus • Hippocampus- brain structure involved in the storage of new information in memory • From the Greek words for “seahorse” • Allows us to take in and combine different components of experience into memories • Involved in the retrieval of information upon recall The Cerebrum: • The cerebrum refers to the upper part of the brain above the pons and cerebellum, divided into two hemispheres. In charge of the most sensory, motor, and cognitive processes • Cerebral hemisphere- the two halves of the cerebrum • Corpus callosum- the bundle of fibers connecting the two cerebral hemispheres • The right cerebral hemisphere is in control of the left side of the body, and the left hemisphere controls the right • Lateralization- specialization of the two cerebral hemispheres for particular operations The Cerebral Cortex: • Cerebral Cortex- a collection of several thin layers of cells covering the cerebrum; it’s largely responsible for higher mental functioning • Cell bodies in the cortex produce a grayish tissue called gray matter • In other parts of the brain myelin axons prevail, providing the brain’s white matter • The cortex has many deep crevices and wrinkles that allow it to contain its billions of neurons in a compact space • Lobes of the cortex: o Occipital lobes- lobes at the lower back of the cerebral cortex containing areas that receive visual information; Latin for “in back of the head” o Parietal lobes- lobes at the top of the brain’s cerebral cortex that contain areas that receive information on pressure, pain, touch, and temperature and handle attention and awareness of spatial relationships; Latin for “pertaining to walls,” at the top of the brain o Temporal lobes- lobes on the sides of the cerebral cortex containing areas involved with hearing, emotion, memory, visual processing, and language comprehension; Latin for “pertaining to the temples”

o Frontal lobes- lobes at the front of the cerebral cortex containing areas involved in movement, working memory, controlling emotions and impulses, higher-order thinking, and speck production; also planning, creative thinking, and empathy The Prefrontal Cortex: • The most forward part of the frontal lobes, accounting for 1/3 of the brain un humans • Associated with reasoning, decision making, and planning • Also has something to do with personality (Phineas Gago)

Section 2.5 The Two Hemispheres of the Brain: • Though similar in structure, these hemispheres have somewhat separate talents (areas of specialization) • In 1861, a French neurologist named Paul Broco noted that individuals with lefthemisphere damages sometimes lost ability to speak or understand language, whereas those with right-hemisphere damage rarely do • Patients with left-hemisphere damage have difficulties with reading, identifying objects, making symbolic gestures or pantomimes, and describe g events in the correct order • Patients with right-hemisphere damage have difficulty identifying faces, interpreting emotional expressions, or understanding music or art; they may get lost easily, even in their own homes Split Brains: A House Divided • In a normal brain, the two hemispheres of the cortex communicate with one another across the corpus callosum • In 1953, Ronald E, Myers and Roger W. Sperry severed the corpus callosum in cats and the nerves leading from the eyes to the brain, this way the left and right eyes only sent to the corresponding side of the brain • In the early 1960s, surgeons tried it on humans to control seizures in patients with debilitating epilepsy; the split-brain surgery reduced seizures but their perception and memory were affected o When shown pictures on slides, they can only verbally describe what is shown to the left hemisphere, but can still respond emotionally with the right o This procedure is still performed, but very rarely The Two Hemispheres: Allies or Opposites? • You can read words faster if the words are flashed to the right visual area because those words go directly to the left hemisphere • You are better at identifying facial expressions flashed to the left visual areas because those faces go directly to the right hemisphere • The right ear goes to the left auditory cortex and is better at processing words • The left ear goes to the right auditory cortex and is better for processing the tone of voice • Right hemisphere also: o Handles problems requiring visual-spacial ability o Creation and appreciation of art and music o Recognizing non-verbal sounds o Some language ability • The left hemisphere is described as having a cognitive style that is rational and analytic

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The right hemisphere is described as being intuitive and holistic In reality, the difference between the two hemispheres is not absolute, but relative—a matter of degree In most real-life activities, they cooperate naturally, for example: In visual perception, the left “sees” the details and the right “sees” how they fit togethe...