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PSYA01 Final Notes.docx

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Steve Joordens

Chapter 1.1: The Science of Psychology Psychology  Is a vast discipline; considered to be a collection of disciplines, composed of many overlapping fields of study  Two unifying qualities  1. Involves study of behaviour; includes perceptions, thoughts, emotions  2. Use of scientific method in work  Psychology: The scientific study of behaviour, thought, and experience  Anthropomorphism: Treating objects or animals like people The Scientific Method  Whether a field of study is considered a science or a specific type of research is scientific is based not on the subject, but on the use of the scientific method  Scientific Method: A way of learning about the world through collecting observations, proposing explanations for the observations, developing theories to explain them, and using the theories to make predictions  Theory → Hypothesis → Test hypothesis → Reject or confirm → Repeat Hypotheses: Making Predictions  Hypothesis: A testable prediction about processes that can be observed or measured  A testable hypothesis is one that can be confirmed or rejected; a scientific hypothesis must be testable  Rules are frequently broken by people claiming to be scientific e.g. astrologers and psychics  Leaves for two courses of action: fully accept prediction or take your chances  Pseudoscience: Refers to ideas that are presented as science but do not actually utilise basic principles of scientific thinking or procedure e.g. horoscopes, fortune telling Theories: Explaining Phenomena  Theory: An explanation for a broad range of observations that also generates new hypotheses and integrates numerous findings into a coherent whole  Theories are built from hypotheses that are repeatedly tested and confirmed  Good theories often become accepted explanations of behaviour or other natural phenomena  Any scientific theory must be falsifiable; can be proven false with new evidence  Theories are not the same thing as opinions or beliefs  All theories are not equally plausible  A measure of a good theory is not the number of people who believe it to be true The Biopsychosocial Model  Biopsychosocial model: A means of explaining behaviour as a product of biological, psychological, and sociocultural factors  Biological influences involve brain structures, chemicals, hormones, drug effects  Sociocultural influences involve family, peers, immediate social situation, ethnicity, gender  Psychological influences involve thoughts, experiences, emotions, personality  Behaviour can be explained usually only if multiple perspectives are incorporated Building Scientific Literacy  Scientific Literacy: The ability to understand, analyse, and apply scientific information  Knowledge gathering → Scientific explanation → Critical thinking → Application  What do we know about this? How can science explain it? Can we critically evaluate the evidence? Why is this relevant? Working the Scientific Model: How We Learn and Remember  Studying techniques using flashcards:  Massing: Breaking up a large pile of cards into smaller groups and moving through each pile separately  Spacing: Leaving the cards in one big stack and moving through them one at a time; compared to massing, there is more time between seeing each individual card  Massing technique seems easier and gives the sense of being more effective, but spacing is actually the better of the two  Experiment: Psychologist Nate Kornell asked 20 student volunteers to practice studying vocab. words for standardized test; tried both massing and spacing methods  Massing study session, studied 20 vocab. terms in four sets of five cards each  Spacing study session, studied another set of 20 vocab. terms in one set of 20  At the end of experiment, memory test administered and found volunteers could remember significantly more from the spaced condition than from massed condition  Concluded that it is better to study by spacing, though many preferred massing  Study does not provide evidence that spacing works for all kinds of learning  Results may be limited to factual and vocabulary learning Critical Thinking, Curiosity, and a Dose of Healthy Skepticism  In 1800s, many entrepreneurs rallied crowds of people claiming to have "miracle product"; usually termed snake oil salesman b/c that's usually what they were selling  Critical Thinking: Involves exercising curiosity and skepticism when evaluating the claims of others, and with our own assumptions and beliefs  For psychologists, critical thinking means applying scientific methods carefully, examining our assumptions and biases, tolerating ambiguity when the evidence is inconclusive  Curiosity is essential to psychology b/c many think about causes of behaviour only when it affects us negatively or strikes as unusual  Psychologists are always curious; ask questions about all kinds of behaviour, such as everyday activities and experiences  Important to approach things with cautious skepticism; constantly told about amazing products claiming to control body weight, improve memory, etc.  Skepticism and curiosity are means of raising important questions; both attitudes lead to search for and evaluate evidence  Steps to critical thinking: 1. Be curious; simple answers are sometimes too simple and common sense not always correct 2. Examine nature and source of evidence; not all research is of equal quality 3. Examine assumptions and biases; includes own assumptions as well as the assumptions of those making claims 4. Avoid overly emotional thinking; emotions can tell us what we value, but not always helpful when it comes to making critical decisions 5. Tolerate ambiguity; most complex issues do not have clear-cut answers 6. Consider alternative viewpoints and alternative interpretations of the evidence  Critical thinking is not a philosophy, belief, or faith, nor is it meant to make everyone arrive at the same answer  Critical thinking cannot guarantee a correct answer, but will help find and justify good answers Myths in Mind: Abducted by Aliens  Principle of Parsimony: The simplest of all competing explanations of a phenomenon should be the one we accept  Following the principle of parsimony typically leads to real answers Chapter 1.2: How Psychology Became a Science Psychology's Philosophical and Scientific Origins  Essentialism: Ascribing significance to certain instances of some objects but not to others e.g. things owned by celebrities more valuable than regular objects  Science is a philosophy of knowledge that stems from two fundamental beliefs:  Empiricism: A philosophical tenet that knowledge comes through experiences; "Seeing is believing". Whatever we see or measure should be observable by anyone else who follows the same methods  Determinism: The belief that all events are governed by lawful, cause-and-effect relationships. Free will vs. determinism.  Psychological science is both empirical and deterministic; our understanding of behaviour comes from observing what we can see and measure and behaviour is caused by a multitude of factors  Zeitgeist: "Spirit of the times"; refers to a general set of beliefs of a particular culture at a specific time in history  Hard for average person in 1600s to view human behaviour as a result of predictable physical laws; would imply philosophy of materialism: the belief that humans, and other living beings, are composed of exclusively of physical matter  Accepting this would mean we lack a self-conscious, self-controlling soul  The opposing belief is dualism: the belief that there are properties of humans that are not physical e.g. a mind or soul separate from the body Influences from Physics: Experimenting with the Mind  One of earliest explorations into scientific psychology made by Gustav Fechner, who worked on sensation and perception  Coined the term psychophysics: The study of the relationship between the physical world and the mental representation of that world  Example: Holding one-pound weight in right hand and a five-pound weight in left. What if a researcher places a quarter-pound weight in each hand, resting on top of existing ones? Which of the quarter-pound weights would be perceived as heavier? Though both weigh the same, the one in right hand will be more noticeable.  Fechner developed an equation to precisely calculate perceived change in weight, then brightness, loudness, etc. Influences from Evolutionary Theory: The Adaptive Functions of Behaviour  Around same time as Fechner, Charles Darwin was studying variety of plants and animals around world  Noticed animal groups that were isolated from one another differed by only minor variations in physical features; seemed to fine-tune the species according to the particular environment in which they lived, making them better equipped for survival and reproduction  Theory of natural selection was based on observations and genetically inherited traits that contribute to survival and reproductive success are more likely to flourish within breeding population  Darwin pointed out behaviour is shaped by natural selection, just as physical traits are  Found survival and reproduction are closely related to individual's ability to recognise some expressions as threats and others as submission Influences from Medicine: Diagnoses and Treatments  Clinical psychology: the field of psychology that concentrates on the diagnosis and treatment of psychological disorders  Brain localization: the idea that certain parts of the brain control specific mental abilities and personality characteristics  Mid-1800s saw two competing views of localization  Phrenology: belief that brain consists of 27 "organs", corresponding to mental traits and dispositions that could be detected by examining the surface of the skull  Study of brain injuries and the ways in which they affect behaviour; had scientific grounding that phrenology lacked  Broca's area: an area of the left side of the brain where speech producttion was localized; patient could only say "Tan", but could hear and understand words  Wernicke's area: patients with damage to this area could speak in sentences that sounded normal, but with unusual or made-up words  Franz Mesmer believed prolonged exposure to magnets could redirect the flow of metallic fluids in body and cure disease and insanity; claim rejected but some of his patients cured after being lulled into a trance  Psychosomatic medicine: "cures" me possible by belief in the treatment  Trances lead to "hypnosis"; caught interest of Freud  Freud interested in how hypnosis cured hysterical paralysis: condition in which individual loses feeling and control in a specific body part  Developed famous theory of psychoanalysis: psychological approach that attempts to explain how behaviour and personality are influenced by unconscious processes  Acknowledged that conscious experiences includes perceptions, thoughts, a sense of self, and sense that we are in control of ourselves  Also believed that in unconscious mind, contained forgotten episodes from early childhood and urges to fulfill self-serving sexual/aggressive impulses  Neglected to conduct scientific experiments, but legacy can be seen in some elements of scientific psychology: 1. Many modern psychologists make inferences about unconscious mental activity 2. The use of medical ideas to treat disorders of emotions, thought, and behaviour, known as medical model, can be traced back to Freud 3. Freud incorporated evolutionary thinking into his work; emphasis on physiological needs and urges relating to survival and reproduction can influence our behaviour The Influence of Social Sciences: Measuring and Comparing Humans  Sir Francis Galton believed that genetics explained psychological differences among people  Noticed great achievement tended to run in families; seemed natural that people who did better in scholarship, business, and wealth were able to do so because they were genetically better people  To support belief, developed ways of measuring eminence: combination of ability, morality, and achievement  Nature and nurture relationships: the inquiry onto how heredity and environment influence behaviour and mental process  Decided on the nature side, ignoring nurturing influences such as upbringing and family traditions  Beliefs and biases led him to pursue justification of eugenics: "good genes"; promotes belief that social programs should encourage intelligent, talented individuals to have children whereas criminals, those with physical or mental disability, and non-White races should be kept out of the English gene pool  Led to mistreatment of many individuals  Biological Psychology: Seeks to explain the underlying genetic, physiological, and brain basis for behaviour The Beginnings of Contemporary Psychology Structuralism and Functionalism: The Beginnings of Psychology  Wundt established first laboratory dedicated to studying human behaviour; responsible for establishing psychology as an independent scientific field  Primary research method was introspection: "to look within"; required trained volunteer to experience a stimulus and then report each individual sensation  Also developed reaction time methods as way of measuring mental effort  One of students, Edward Titchener, adopted same method of introspection to devise map of structure of human consciousness  Structuralism: An attempt to analyse conscious experience by breaking it down into basic elements, and to understand how these elements work together  Believed mental experiences were made up of a limited number of sensations, which were analogous to elements in physics and chemistry; different sensations can form and create complex compounds  William James sought to understand how the mind functions; in contrast to structuralism, which looks for permanent, unchanging elements of thought, James influenced by Darwin, so preferred to examine behaviour in context  Functionalism: The study of the purpose and function of behaviour and conscious experience  Evolutionary psychology: An approach that interprets and explains modern human behaviour in terms of forces acting upon our distant ancestors; belief that our brains and behaviours have been shaped by the physical and social environment that our ancestors encountered The Rise of Behaviourism  Edwin Twitmyer one of first biologists interested in how organisms learn to anticipate their bodily functions  Experiment Rubber mallet hitting knee and bell ringing just before; caused leg to kick. Failed b/c bell rang, but mallet didn't hit. However, leg kicked anyway. Process called classical conditioning  Behaviourism: An approach that has a singular focus on studying only observable behaviour, with little to no reference to mental events or instincts as possible influences on behaviour  John Watson believed that all behaviour could ultimately be explained through conditioning; believed so much in the power of experience and little in genetics, thought he could engineer a personality however he wished Humanistic Psychology Emerges  Humanistic psychology: Focuses on the unique aspects of each individual human, each person's freedom to act, his or her rational thought, and the belief that humans are fundamentally different from other animals  Major figures include Carl Rogers and Abraham Maslow; both focused on the positive aspects of humanity and the factors that lead to a productive and fulfilling life  Humanistic psychologists sought to understand the meaning of personal experience; believed that people could attain mental well-being and satisfaction through gaining a greater understanding of selves, rather than being diagnosed with disorder The Cognitive Revolution  Hermann Ebbinghaus produced reams of data on remembering and forgetting; results of studies produced "forgetting curves", which showed that most of what people learn will be forgotten rapidly, but then forgetting slows to a crawl  Frederick Bartlett able to illustrate that memory is interpretive process that involves cultural knowledge  Demonstrated that we are more likely to remember the general storyline of movies than other details  Gestalt psychology: Approach emphasizing that psychologists need to focus on the whole perception and experience, rather than its parts; "complete form of an object"  Cognitive psychology: A modern psychological perspective that focuses on processes such as memory, thinking, and language Social and Cultural Influences  Social and personality psychology: study of the influence of other people on our behaviour along with what makes each individual unique  Kurt Lewin, founder of modern social psychology, made observation: behaviour is a function of the individual and the environment; all behaviours could be predicted and explained through understanding how an individual with a specific set of traits would respond in a context that involves a specific set of conditions  Cross-cultural psychology: Field that draws comparisons about individual and group behaviour among cultures; helps us understand the role of society in shaping behaviour, beliefs, and values Chapter 1.3 Putting Psychology to Work: Careers in Psychology and Related Fields Professions in Psychology Research and Teaching  Research psychologists work at universities, in corporations, in the military, and in governmental agencies; focus on applying basic principles of psychology to real-world settings  Applied psychology: Uses psychological knowledge to address problems and issues across various settings and professions, including law, education, etc.  Academic psychologists work at colleges and universities, combining teaching with conducting research; usually refer to selves by their specializations e.g. social psychologist Psychological Health and Well-being  Psychiatry: Branch of medicine concerned with the treatment of mental and behavioural disorders; psychiatrists prescribe drugs such as antidepressants  Forensic psychology: Encompasses work in the criminal justice system, including interactions with the legal system and its professionals  School psychology: Involves working with students who have special needs, such as those with emotional, social, or academic problems Health and Medical Professions  Health psychology: the study of how individual, biological, and environmental factors affect physical health Psychology in the Corporate World  Industrial/Organizational psychology: A branch of applied psychology in which psychologists work for businesses and other organizations to improve employee productivity and the organizational structure of the company or business  Human factors psychology: Study of how people interact with tools, physical spaces, or products  Environmental Psychology: Study factors that improve working and living conditions, but they do so by establishing how the environment affects individuals or groups Chapter 2.1 Principles of Scientific Research  Objectivity: Assumes that certain facts about the world can be observed and tested independently from the individual who describes them; everyone should be able to agree on these facts given the same tools, the same methods, and the same context  Subjective: Knowledge of the event is shaped by prior beliefs, expectations, experiences, and mood The Five Characteristics of Quality Research 1. It is based on measurements that are objective, valid, and reliable 2. It can be generalised 3. It uses techniques that reduce bias. 4. It is made public. 5. It can be replicated. Scientific Measurement: Objectivity, Reliability, and Validity  Objective measurements: The measure of an entity or behaviour that, within an allowed margin of error, is consistent across instruments and observers e.g. a single object should weigh the same using multiple functioning scales  Variable: Refers to the object, concept, or event being measured  Self-reporting: A method in which responses are provided directly by the people who are being studied, typically through face-to-face interviews, phone surveys, paper and pencil tests, and web-based questionnaires  Operational definitions: Statements that describe the procedures and specific measurements that are used to record observations  Reliability: When a measure provides consistent and stable answers across multiple observations and points in time  Validity: The degree to which an instrument or procedure actually measures what it claims to measure. Generalizability of Results  Generalizability: Refers to the degree to which one set of results can be applied to other situations, individuals, or events  Population: The group that researchers want to generalize about  Sample: A select group of population members  Random sample: Every individual of a population has an equal chance of being included  Convenience samples: Samples of individuals who are the most readily available  Laboratory research: Includes any study conducted in an environment controlled by the researcher  Naturalistic research: Takes place where the behaviour would typically occur  Ecological validity: The degree to which the results of a laboratory study can be applied to or repeated in the natural environment Sources of Bias in Psychological Research  Hawthorne effect: A term used to describe situations in which behaviour changes as a result of being observed Working the Scientific Literacy Model: Demand Characteristics and Participant Behaviour  Demand characteristics: Inadvertent cues given by the experimenter or experimental context that provide information about how participants are expected to behave  Social desirability: Research participants respond in ways that increase the chances that they will be viewed favourably  Placebo effect: A measureable and experienced improvement in health or behaviour that cannot be attributable to a medication or treatment Techniques that Reduce Bias  Anonymity: Each individual's responses are recorded without any name or other personal information  Confidentiality: Results will be seen only by the researcher  Ensuring anonymity and confidentiality are important steps toward gathering honest responses from participants  Participant anxiety can be reduced when provided full information about how they will eventually use the data  Single-blind study: The participants do not know the true purpose of the study, or else do not know which type of treatment they are receiving  Double-blind study: Neither the participant nor the experimenter knows the exact treatment for any individual Sharing the Results  A very important aspect of science is having the opportunity to repeat someone else's study to confirm or reject that researcher's observations and findings  Psychology's primary mode of communication comprises of academic journals; represent primary research or reviews of multiple studies on a single topic  Peer review: A process in which papers submitted for publication in scholarly journals are read and critiqued by experts in the specific field of study  First, editor receives manuscript from the researcher and determines whether it is appropriate subject matter for the journal  Second, editor sends copies of the manuscript to a select group of peer reviewers  Replication: The process of repeating a study and finding a similar outcome each time. Risky Paths to Truth: Anecdotes, Authority, and Common Sense  Good research uses valid, objective measures; poor research uses subjective measures that are less valid, less reliable, less likely to be replicated  Poor evidence comes most often in one of three varieties: anecdotes, appeals to authority, and common sense  Anecdotal evidence: An individual's story or testimony about an observation or event that is used to make a claim as evidence e.g. weight loss stories  Appeal to authority: The belief in an "expert's" claim even when no supporting data or scientific evidence is present  Appeal to common sense: A claim that appears to be sound, but lacks supporting scientific evidence e.g. believing world was the stationary center of the universe; idea that Earth could orbit the sun at blinding speeds was deemed nonsense  Appeal to tradition: "We have always done it this way!"  Appeals to novelty: "It is the latest thing!" Chapter 2.2 Scientific Research Designs  Research designs: Guide investigators in organizing the study, making observations, and evaluating the results  Characteristics of all research designs: variables, operational definitions, and data Descriptive Research  Opportunity to present observations about the characteristics of the subject  To answer descriptive research questions, must gather data using either case studies, naturalistic observation, or surveys and questionnaires  Case study: An in-depth report about details of a specific case  Naturalistic observation: Unobtrusively observing and recording behaviour as it occurs in the subject's natural environment Correlational Research  Correlational research: Involves measuring the degree of association between two or more variables  Direction: positive or negative; move up/down together, or one up and one down  Strength: Correlation coefficient; -1.0 to +1.0; closer to absolute 1.0, stronger relationship  Correlation coefficient is only a measure of association, not causality; correlation gives the impression that one variable causes the other  Third variable problem: Refers to the possibility that a third, unmeasured variable is actually responsible for a well-established correlation between two variables  Illusionary correlations: Relationships that really exist only in the mind, rather than in reality Experimental Research The Experimental Method  Random assignment: A technique for dividing samples into two or more groups  Confounding Variables: Variables outside of the researcher's control that might affect the result e.g. genes, mood, personality  Experimental group: Group in the experiment that is exposed to the independent variable  Control group: Does not receive the treatment; serves as comparison The Quasi-Experimental Method  Quasi-experimental research: Research technique in which the two or more groups that are compared are selected based on predetermined characteristics rather than random assignment  Q-E experiments are actually correlational studies; can point out relationships, but cannot determine what it is about those groups that lead to the differences Chapter 2.3 Ethics in Psychological Research Promoting the Welfare of Research Participants  Institutional review board: Committee of researchers and officials at an institution charged with the protection of human research participants; intended to protect individuals by weighing potential risks to the volunteers against the possible benefits of the research and it requires that volunteers agree to participate in the research Obtaining Informed Consent  Informed consent: A potential volunteer must be informed and give consent without pressure  Volunteers must be told at least: 1. The topic of the study 2.The nature of any stimuli to which they will be exposed 3.The nature of any tasks they will complete 4.The approximate duration of the study 5.Any potential physical, psychological, or social risks involved 6.The steps that the researchers have taken to minimize those risks  Deception: Misleading or only partially informing participants of the true topic or hypothesis under investigation; "white lie"  Debriefing: The researchers explain the true nature of the study, and especially the nature of and reason for the deception  Freedom to choose, equal opportunities, the right to withdraw, the right to withhold responses Chapter 2.4 A Statistical Primer Descriptive Statistics  Descriptive statistics: A set of techniques used to organise, summarise, and interpret data; used to describe and understand three types: frequency, central tendency, variability Frequency  Frequency: The number of observations that fall within a certain category/range of scores  Appears on the vertical axis on graph  Normal distribution: A symmetrical distribution with values clustered around a central, mean value  Negatively skewed distribution: When the curve has an extended tail to the left of the cluster  Positively skewed distribution: Long tail on the right of the cluster Central Tendency  Central tendency: A measure of the central point of a distribution  Mean, median, mode Variability  Variability: The degree to which the scores are dispersed in a distribution  Standard deviation: Measure of variability around the mean Hypothesis Testing: Evaluating the Outcome of the Study  Statistical significance: The means of the groups are farther apart than you would expect them to be by random chance alone  Hypothesis test: A statistical method of evaluating whether differences among groups are meaningful, or could have been arrived at by chance alone Chapter 3.1 Genetic and Evolutionary Perspectives on Behaviour Heredity and Behaviour  Research has made it clear that behaviours are influenced by genes just as physical characteristics are  This research involves comparing people of differing levels of relatedness or studying specific genes at the molecular level The Genetic Code  Genes: Basic units of heredity; responsible for guiding process of creating the proteins that make up our physical structures and regulate development and physiological processes throughout the lifespan.  Genes are organized along chromosomes: Structures in the cellular nucleus that are lined with all of the genes an individual inherits  Humans have approx. 30k genes distributed across 23 pairs of chromosomes, half contributed from mother and half from father  Genes are comprised of DNA: Deoxyribonucleic acid; a molecule formed in a double-helix shape that contains four amino acids: adenine, cytosine, guanine and thymine  Each gene is unique combo of these 4 amino acids, e.g. AGCCTAATCG  Sequence represents code used to create proteins  Genes instruct cells how to behave, which type of molecules to produce, when to produce  Genotype: Refers to the genetic makeup of an organism  The unique set of genes that compose every chromosome represents the genotype of the individual  Phenotype: Consists of the observable characteristics, including physical structures and behaviours  Genotype represents what was inherited, phenotype represents the physical and behavioural manifestation of the genotype through interactions with the environment  Genes come in pairs, one inherited from each parent; if two corresponding genes at a given location on a pair of chromosomes are the same, referred to as homozygous; if different, called heterozygous Behavioural Genetics: Twin and Adoption Studies  Behavioural genetics: The study of how genes and environment influence behaviour  Behavioural genetic methods applied to humans typically involve comparing people of different levels of relatedness, e.g. parents and offspring, siblings, etc.  Monozygotic twins: Come from a single ovum (egg), which makes them genetically identical  Dizygotic twins: Come from two separate eggs fertilized by two different sperm cells that share the same womb  Heritability: A statistic, expressed as a number between 0 to 1, that represents the degree to which genetic differences between individuals contribute to differences in a behaviour or trait found in a population  Heritability of 0 means genes do not contribute to individual differences in a trait, whereas 1 means genes account for all individual differences in a trait  Also study adoptive children to estimate genetic contributions to behaviour; adopted family represents nurture while biological family represents nature side  Young adopted children are more similar to their adoptive parents in intelligence levels than they are to their biological parents  By age of 16, adopted score more similarly to their biological parents  For intelligence, heritability seems to increase with age; opposite for anxiety/depression Behavioural Genomics: The Molecular Approach  Behavioural genomics: The study of DNA and the ways in which specific genes are related to behaviour Evolutionary Insights into Human Behaviour Evolutionary Psychology  Heritable traits, both physical and behavioural, pass from one generation to the next through sexual reproduction  Some traits, called adaptations, contribute to survival, health, and sexual behaviour  Evolution: The change in the frequency of genes occurring in an interbreeding population over generations  Natural selection: The process by which favourable traits become increasingly common in a population of interbreeding individuals, while traits that are unfavourable become less common Chapter 3.2 How the Nervous System Works: Cells and Neurotransmitters Neural Communication  Neurons: One of the major types of cells found in the nervous system, which are responsible for sending and receiving messages throughout the body  Neurons come in many varieties; some extend from the spinal cord out to the extremities, others are very short and may end almost as soon as they begin  Cell body: Also known as the soma, is the part of a neuron that contains the nucleus that houses the cell's genetic material  Dendrites: The small branches radiating from the cell body, receive messages from other cells and transmit the message toward the cell body  Axon: The structure that transports information from the neuron to neighbouring neurons in the form of electrochemical reactions; at the end of axons are axon terminals  Neurotransmitters: Chemicals located within the axon terminals that function as messengers allowing neurons to communicate with each other  Synapses: The microscopically small spaces that separate individual nerve cells; neurotransmitters are released across these  Sensory neurons: Fetch information from bodily senses and bring it towards the brain  Motor neurons: Carry messages away from the brain and spinal cord and toward muscles in order to control their flexion and extension Glial Cells  Myelin: A fatty sheath that insulates axons from one another, resulting in increased speed and efficiency of neural communication  Multiple sclerosis: A disease in which the immune system does not recognise myelin and attacks it, which devastates the structural and functional integrity of the nervous system  Myelin is made from a highly abundant type of cell called glia  Glial cells: Specialised cells of the nervous system that are involved in mounting immune responses in the brain, removing wastes, and synchronizing activity of the billions of neurons that constitute the nervous system  Outnumber neurons in the brain by a ratio of 10:1  The activity of neurons is highly dependent on interactions with glial cells The Neuron's Electrical System: Resting and Action Potentials  Resting potential: A neuron's relatively stable state during which the cell is not transmitting messages  During this, the outside of the neuron has a relatively high concentration of positively charged ions, while interior of the axon has fewer positively charged ions as well as relatively high concentration of negatively charge chloride ions  Neural firing: When neurons are stimulated and spring into action  When a neuron is stimulated, pores of its membrane surface open up and allow positively charged sodium ions to rush in; if sufficient number enter, will alter the charge on inside to be greater than -70mV  Each neuron has a specific threshold that must be reached before firing  Action potential: A wave of electrical activity that originates at the base of the axon and rapidly travels down its length  When action potential reaches the axon terminals, neurotransmitters are released into synaptic cleft: the minute space between the terminal button and the dendrite, and bind to receptors on dendrites of neighbouring neurons  Refractory period: Brief period in which neurons cannot fire  All-or-none principle: Individual nerve cells fire at the same strength every time an action potential occurs; neurons do not "sort of" fire or "over fire", just fire The Chemical Messengers: Neurotransmitters and Hormones  When neurotransmitters are released at the axon terminal, they cross the synapse and fit in a particular receptor of the dendrite like a key in a lock  If neurotransmitter binds to the receptor, it will trigger one of two types of reaction in the receiving neuron: excitatory, increasing action potentials, or inhibitory, decreasing action potentials  After neurotransmitter molecules have bound to postsynaptic receptors of a neighbouring cell, they are released back into the synaptic cleft where they may be broken down by enzymes  Others might go through reuptake: Process whereby neurotransmitter molecules that have been released into the synapse are reabsorbed into the axon terminals of the presynaptic neuron; natural recycling system for neurotransmitters Types of Neurotransmitters  Monoamines are one class; each of the monoamines has its own unique function, although there is some degree of overlap  Dopamine: is a monoamine neurotransmitter involved in such varied functions as mood, control of voluntary movement, and processing of rewarding experiences  Serotonin: Involved in regulating mood, sleep, and appetite  Norepinephrine: Monoamine synthesized from dopamine molecules that is involved in regulating stress responses, including increasing arousal, attention, and heart rate  Acetylcholine: One of most widespread neurotransmitters within the body; found at the junctions between nerve cells and skeletal muscles; very important for voluntary movement  GABA (gamma-amino butyric acid): A primary inhibitory neurotransmitter of the nervous system, meaning that it prevents neurons from generating action potentials  Reduces the negative charge of neighbouring neurons even further than their resting state  When binds to receptors, causes influx of negatively charged chloride ions to enter the cell, opposite effect of when a neuron is stimulated  Glutamate: An excitatory neurotransmitter in the nervous system that is critical to the processes of learning and memory  Substance P: Neurotransmitter involved in the experience of pain; can be found in sensory nerves in the brain and spinal cord  Capsaicin: Pain-inducing compound found on many types of chili peppers  Congenital insensitivity to pain: Lacking the ability to perceive pain Drug Effects on Neurotransmission  Agonists: Drugs that enhance or mimic the effects of a neurotransmitter's action  Drugs can behave as agonists either directly or indirectly; drugs that behave directly physically bind to receptors at the postsynaptic cells; drugs that behave indirectly facilitates neurotransmission by increasing the release and availability of neurotransmitters  Antagonists: Inhibit neurotransmitter activity by blocking receptors or preventing synthesis of a neurotransmitter e.g. Botox Hormones and the Endocrine System  Hormones: Chemicals secreted by the glands of the endocrine system  Neurotransmitters work almost immediately within the microscopic space of the synapse, whereas hormones are secreted into the bloodstream and travel throughout the body  With nervous system, endocrine system contributes to homeostasis: balance of energy, metabolism, body temperature, and other basic functions that keep body working properly  Hypothalamus: Brain structure that regulates basic biological needs and motivational systems; acts as thermostat, maintaining appropriate body temperature; stimulates the pituitary gland: the master gland of the endocrine system that produces hormones and sends commands about hormone production to the other glands  Adrenal glands: A pair of endocrine glands located adjacent to the kidneys that release stress hormones, such as cortisol and epinephrine; both help mobilise body during stress  Endorphin: Hormone produced by the pituitary gland and the hypothalamus that functions to reduce pain and induce feelings of pleasure; released during events such as strenuous exercise, sexual activity, or injury  Testosterone: Hormone that serves multiple functions, including driving physical and sexual development over the long term and surging during sexual activity and in response to threats; often cited as explanation for behaviour  Hormones don't necessarily c
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