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PSYC31/C32 CH 1-6 Textbook Notes (First Midterm)

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Steve Joordens

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Chapter 1 Case Vignette - moving vehicle accidents most common reason for traumatic brain injuries, occurring more frequently in males than females What is Clinical Neuropsychology? clinical neuropsychology- division of psychology that specializes in the clinical assessment and treatment of patients with brain injury or neuro- cognitive deficits. it is considered an applied field because it deals with assessment, diagnosis, and treatment of those individuals with brain illness or injury as opposed to only looking at brain functions and structures. experimental neuropsychology- field of psychology that focuses on brain-behaviour relationships usually using animals as subjects. it does so by describing structures and functions, rather than focusing on assessment, diagnosis, treatment. Historical Background - dates back to beginning of 20th century. the term neuropsychology first used by Sir william Osler. Even though the field is relatively recent, study of brain, goes back to civilization. Ancient Hypotheses to Modern Theories of Brain Functioning Neolothic Period or Stone Age trephination- oldest known surgical technique in which small piece of bone is removed from skull, leaving a hole in the skull, the procedure has been done for medical and religious reasons. It was done on people who were not accepted by their culture, such as hallucinators, schizophrenics, to release the evil spirits. - it removes a bony portion of the cranial vault. clearly its a crude way to treat brain bc it involves exposure of brain tissue to elements and various forms of disease and infection. surgeons performing this procedure though were skilled and aware of the infections it could cause. The Egyptians 3rd dynasty, not really advanced in their understanding of the brain. - during mummification, brain was discarded even though all other organs were felt to be important - Imhotep, founder of Egyptian medicine and original author of papyrus. - Edwin Smith Surgical Papyrus- early Egyptian manuscript which described techniques used to treat various forms of difficulties including brain trauma. it is one of the first brain-behaviour relationship- a relationship that exists between certain functions of the brain and overt behaviours. - papyrus from Smith contained 2 sections, one was authentic and the other was not. - James Breasted read the document in 1930, which showed no indications on surgeries performed, gave reference to CSF. there were no operating procedures involved, but ways to reduce intracranial hemorrhaging, removal of fragments of bone from ear canal andblood clots from sinuses. - it also contained prescriptions for head wounds, using fats from different animals - Eber papyrus contains 900 prescriptions for ailments in various parts of body, using different ingredients including urine and feces. this papyrus contained more supernatural forms of healing than Edwin Smith -Herophilus and Erasistratus of Alexandria were first individuals to propose brain as a centre of reason, by providing first accurate description of human brain, including ventricles. they conducted most work on cadavers and used criminals for vivisection, dissection of body while it is still living. - new theory in Middle Ages, claiming that fluid0filled compartments of brain were responsible for higher menta, as well as spiritual processes. cavities were thought as cells, lateral ventricles forming first cell, third ventricle second, fourth ventricle third. ventricular localization hypothesis- hypothesis that mental and spiritual processes reside within ventricular canals, later called "cell doctrine." - today we know that ventricles are sites that produce and transport CSF, which cushions brain within skull, made in choroid plexuses, flows through ventricles and subarachnoid space. Ancient Greeks - Heralitus, called mind an enormous space whose boundaries we could never reach. he believed that universe is in constant change and there is an underlying order or reason to the change.most significant philosopher of ancient Greece before Socrates and plato. - Pythogoras, suggested brain was organ responsible for human thought helped form brain hypothesis- hypothesis that brain is the source of human thought and behaviour. - Pythogoreans followers of Pythogoras, believed in natural science and philosophy. they lived together in group and followed ethical code of conduct. - Hippocrates, best known for hippocratic oath- an agreement that Hippcrates demanded of physicians ensuring that they would do no harm in their quest to appropriately treat their patients - he believed that brain controlled all sensing and movements, and indicated that damage to one side of brain affected other side of body, aka contralateral control. - practised holistic medicine- treats entire patients, involves physical, psychological, spiritual aspects of healing. - Plato believed that soul was divided into three functions; appetite, reason, and temper, all residing in the brain, because the brain was close to heavens. - he imposed many mind-body question- philosophical questions regarding the relationship between the physical body and the spiritual mind. - credited with earliest reference to mental heath, as he suggested that a balance between all pats of life lead to good metal health - Aristotle, believed brain was without blood and functioned to cool hot blood as it came from the heart. he designed the cardiac hypothesis= that heart is centre of rational thought The Romans - Galen misunderstood ventricles and believed in ventricular localization theory; thinking that they housed animal spirits, produced in the chroid plexus. he also believed that functions of body and brain were based on balance of bodily humours; blood, mucus, and yellow and black bile were responsible for functioning of body and brain. He was very interested in study of stroke, called apoplexy a the time. he believed it resulted from accumulation of black bile in ventricles, or from obstruction of flow of animal spirits. The Middle Ages - Aristotle's views were considered very sacred until 13th century, Albertus Magnus theorized behaviour resulting from combination of brain structures including cortex, midbrain, and cerebellum. Renaissance Europe - began in italy in mid14th -16th. - plague was a great factor in start of the Renaissancem leading to freer inquiry and thought. - Da Vinci could disprove the ventricular localization theory as he secretly dissected cadavers, but held to this belief and we do not know why. - Andreas Vesalius, published first accurate book on human anatomy called On the Workings of the Human Body, one of the most medical science books ever written. he proved Galen's view as wrong - believed that to study human you need to dissect human, none believed his views at the time tho -Descartes believed in dualism- view that within each person resides two entities, mind with mental properties, and body with physical properties. this is the opposite of monoism- view that there is only one basic and fundamental reality, that all existence is this one reality, hence they operate according to the same principles. - he believed that mental processes reside in the pineal gland, bc it was the only structure not composed of bilaterally symmetrical halves. he viewed the cortex as a covering of the pineal body. -Thomas Willis, known for study of blood circulation and for whom Circle of Willis is named. he used clinical evidence form living patients with movement disorders, also described sensations residing with corpus striatum. he stated that cerebral gyro controlled memory and will, imagination was also cerebral function located in corpus callosum. corpus striatum was thought tone related to sensations and movement, cerebellum controlled voluntary/.involuntary systems, and pons/medullla were part of cerebellum. - he was first person in renaissance period to divide brain into functional parts base on comparative anatomy, theory, and coin practice. - Emanuel Swedenboorg, concluded cerebral cortex was source of understanding, thinking, judging, willing. he was not accepted much bc he began to have visions 18th Century: Localization Theory Localization of brain functioning- theory that certain abilities are localized to certain areas of brain. - Gall correlated 27 faculties of mind with skull features and located abilities on maps of both hemisphere. phrenology- inaccurate theory developed by Gall which stated that bumps on head related to certain abilities residing within brain led to belief in reading bumps and increasing abilities by rubbing corresponding bumps. - these ideas began to be practiced in salons of Europe. - Gall was also responsible for discoveries in neuroanatomy and neurophysiology, some of the earliest views on idea of localization of functions. - proposed that cortex and sulci and gyro were functioning parts of brain, not just coverings of pineal body. a large pathway, the pyramidal tract, leads form cortex to spinal cord, implying that cortex sends info to spin cord to command movement of muscles. - his student Johann Spurzheim, worked with him but Spur left bc he felt there were no bad or evil functions. - Pierre Flourens disputed that no localization of function within cortex, he did ablation, a type of surgery in which removing part of the brain led to generalized, not localized, disorders of behaviour. he claimed that no specific localization of ability, rather amount of extent of tissue damage is what mattered. so basically, the greater amount of impaired tissue, the more dysfunctional the individual will appear. - he also sated that brain operated in integrated fashion, not with discrete functions. he was describing the modern term neuroplasticity- brains neutral ability to form new connections to compensate for injury or changes in one's environment. - this is possible bc brain functions as a whole, similar to the way he described. he believed that cerebellum was responsible for coordinated movement and that medulla required for basic life functioning. 19th Century Advances -scientific method- method of research in which problem is identified, hypothesis is formulated, relevant data gathered, from these data, cause- effect relationships can be stated. - Wilhem Wundt created first psych lab in Germany. - through scientific methods researchers are able to make cause and effect statements for the first time. - Philliple Pinel, french physician, became head of two asylums, and introduced kindness and humanity in treatment of the patents. - at the same tim, William Tuke, cared for patients in England. Dorothea Dix, Eli Todd, Clifford Beers(A Mind that Found Itself: An Autobiography) - this book is about Beer's experience with bipolar disorder and his treatment, - mental hygiene movement: movement to treat psychiatric patients with kindness, dignity. it instigated release of mental patients from prison and the building of mental hospitals. - moral therapy- created for mental patients based on ideas of mental hygiene movement; kindness and respect. - diagnostic classification systems- for classifying medical and psychiatric disorders, it lists symptoms of a particular disorder and various other important facts for diagnosis; in psychology, refers to DSM-IVTR - Emil Kraeplin, categorized mental illness as endogenous(curable) and exogenours(incurable) - Darwin, conceptualized origin of species; survival value Localization of Brain Functioning Areas: Higher Cortical Areas - Gall and Swedenborg looked at various types of localization; but it took a longer time to look into the localization of higher cortical functioning. - Paul Broca, localization of language within left hemisphere, but his work was based on other people as well. - Bouilard found that brain had several social organs, one was related to speech and difficulties with speech, when the organ was damaged. - Aubertin, his son in law, argued that there were specific higher order cognitive functions localized within certain areas - Marc Dax, french neurologist, discovered link between damage to left cerebral hemisphere and loss of ability to produce speech, died without publishing his findings. then Gustave Dax, his son, published his work with his own findings as well, but 6 weeks before Broca did, and they both had the same findings - Broca examined patients who could speak coherently but could not understand the spoken word. - area in posterior, lower region of left frontal lobe, became Broca's area. he also found that language production was in left hemisphere - lateralization; idea hat certain abilities reside in one side of the brain or other, for majority of individuals, verbal abilities reside in left h, spatial abilities in right h, - aphasia; inability to use or comprehend language. - Carl Wernicke, found second language area of brain - temporal lobe, to the posterior and inferior to Broca's area, damage here led to inability to make sense with language even though utterances were grammatically correct whether spoken or written. - expressive language located in frontal lobes, receptive language located in temporal lobe - damage to nerve fibres connecting Wernicke's and Broca's areas result in arcuate fasciaculus, resulting in conduction aphasia; inability in both reception and production of language. - Broca's aphasia; can understand what is spoken but has difficulty responding in grammatically correct manner (E has this) - Wernicke's aphasia; can grammatically produce speech with content inappropriate to question - Conduction aphasia; neither understands question not responds grammatically. - John Huglings Jackson, disagreed with all these aphasias, and saw the brain as functioning in a hierarchical manner, as each level controls more complex functions. the three levels were spinal cord, brain stem, and forebrain. - Lashley believed in localization and equipotentiality; idea that mental abilities depend upon entire brain functioning as a whole - also proposed the principle of mass action basically that the extent of brain's impairment is directly proportional to amount of tissue damage - Alexander Luria described each area of central nervous system involved in one or more brain functions. the first area regulates arousal level of brain and proper muscle tone. second area's role is reception and analysis of sensory inf from external and internal environments. third was involved with planning, executing, verifying behaviour. - Roger Sperryl studied split-brain; conducted on humans with severed corpus callouss, to determine extent to communication between two hemisphere. (corpus callosum is a large mass of myelinated axons which connect left/right hemispheres, and allow communication between the two ) - Ward Halstead developed neuropsych labs in Chicagoe, began assessing brain impairment. with the help of Ralph Reitan, created the Halstead0 Reitan Neuropsych Test Battery; designed to be administered in standardized fashion to all subjects and allowed for comparability between, - Lurai-Nbraska Battery designed to fit needs of individual patient and admin of test could be altered to fit individual needs more useful in forensic situations. The Development of Clinical Neuropsychology as a Profession - similarities between WW1,2 and brat Depression was cases of PTSD experienced by individuals - Veterasns Administation, US Government agency created to service physical and mental health needs of those who served in armed forces, helped. - Korean War and Vietnam Conflict led to more brain issues. initially leading to PTSD- mental disorder occurring after traumatic event outside range of usual human experience and characterized by symptoms like reliving the event, reduced involvement with others, exaggerated starle response,(aka shell shock, battle fatigue) Clinical Neuropsychology as a Subspecialty of Clinical Psychology -- clinical psychology- branch of psychology devoted to assessment, diagnosis, treatment of mental and behavioural disorders - Boulder Model, developed framework for training of clinical psychologists; guidelines termed scientist-practioner model, which basically state that to be accredited by APA, clinical or counselling doctoral program must contain prescribed number of classes or credits in scientific basis of behaviour and certain classes/credits in practise of psychology. - clin neuropsyhcologist is PHD level, with the following: - completion of systematic didactic experiential training in neuropsych and neuroscience in uni - 2 or more years of supervised training applying services in clinical setting - licensing and certification to provide psychological serves to public by laws of state/province - review by one's peers as test of those competencies - 3 major organizations existing for perpetuation of clinical neuropsychologyl Division 40, INS, and NAN. Methodology Specific to Clinical Neuropsychology Subjects - main questions for neuropsychologist is type of subject from which research findings have ben taken; usually through a cases study method. Techniques Dealing with Subject Variables - double dissociation technique- lesions have opposite or dissimilar effects on two distinct cognitive functions; develop to help determine when cognitive functions are independent. - lesion approach; lesioning of animals and sometimes humans to study effects of lesions of various brain functions. when its used with humans its usually in areas where individual has difficult for which lesion should help eradicate the difficulty. But for animals, lesions are used to create deficits and observe functioning afterwards Imaging Techniques in the Study of the Human Brain Electrical Techniques - EEG- record of brain wave patterns as individual complete a task. first and oldest technique to record electrical activity (ELECTROENCEPHALOGRAPHY) - evoked potential; ability to record changes in EEG activity in response to sensory stimuli; response is termed evoked potental/ event related potential Radiological Tecniques - Xrays- imaging method, radiates effect in density of different parts of brain to various degrees, a method of enhancing X-ray is pneumoencephalography; in which a small amount of CSF is removed and replaced by air. car is taken as air moves up spinal cord, and bc of the air, the ventricles stand out clearly. tis is a v painful procedure tho.Angiography, is similar to tis, uses radiopaque substance to allow visualization of blood vessels. - CT Scan, based on multiple X-ray images of brain, provides 3D perspective of brain with clear differentiation of brain structures. the fluids are a lll diff colours, allows between view of the dysfunctional area. SPECT- Single Photon Emission Tomography- similar to CT BUT simpler and inexpensive. basicallyy the emission of single photons of a given energy form radioactive probes, the emissions are used to construct images of probes located within body, thereby detailing flow of blood in given area Dynamic Brain Imaging - PET-Positron Emission Tomography; visualized brain activity based on cerebral blow flow; tracks metabolism of glucose, oxygen, neurotransmitters. - MRI; Magnetic Resonance Imaging; use of magnetic fields; gives clearer image than CT scan, less dangerous bc does not use radiation. excellent bc it observes brain metabolism and nutrients distribution. - FMRI is like MRI, allowing detection of increased/decreased blood flow in particular areas of brain. does not involve radiation exposure. Brain Simulation Intracranial brain stimulation- stimulation of brain tissue used in treatment of various central nervous system diseases like Parkinson's. used more as an adjunct to various forms of treatment. difficult is that its invasive needing skull to open to insert electrode. Transcranial Magnetic Stimulation- procedure in which brain is stimulated through skull. CHAPTER 2- THE NERVOUS SYSTEM: STRUCTURE AND FUNCTION Central Nervous System Prenatal Development: External Factors - Prenatal Development refers to all steps involved with formation of various structures and functions of body, specifically central nervous system. - proper nutrition is crucial for development of proper CNS, as fetal difficulties like low birth weight, smaller head is caused by malnutrition. - alcohol/drug consumption is very bad and leads to difficulties. fetal alcohol syndrome, causes cognitive difficulties, directly related to alcohol consumption. Increased stress raises cortisol level in body, basically a steroid hormone released by adrenal cortex that elevates blood sugar and metabolism, helps body adapt to prolonged stress. excess cortisol is based bc it may lead to depression of immune system and commence various illnesses' in one's body, like pneumonia, bronchitis, etc. - physical abuse also leads to developmental complications, shaken baby syndrome, can result from it and lead to traumatic brain injury. this is basically when the baby is shaken so hard that the skull is impacted. emotional abuse can also lead to developmental issues. Development of the Central Nervous System (CNS) dorsal--> superior (towards back or toward top of brain) ventral--> inferior ( towards belly or bottom of brain) rostral--> anterior (towards head) caudal--> posterior(towards rear or away from head) - germinal period is time between conception and 2 weeks later. - developing cells are called zygote, end of 1st week blastocyt is formed, a mass of cells with fluid centre. it includes the trophoblas, which provides nutrition. after implantation, it is an embryo, and embryonic stage ends until first trimester. it has 3 layers; ectoderm; outermost, develops into skin, sense organs, nervous system. mesoderm; middle layer,becomes muscles, blood, excretory system. endoderm; innermost later, digestive system, lungs, other internal organs. Amnion is a sack of flux in which embryo floats for temperature regulation and protection. umbilical cord connects embryo to placenta, a group of tissues in which blood vessels from embryo and mix but don't join. - development of nervous system begins with neural plate; made of ectodermal tissue on dorsal surface of developing embryo. it is induced by signals from mesoderm later. as it becomes evident, cells are totipotent, able to become any cell in the body, and as it develops, the cells lose this ability and become specific to central nervous system development. within time, neural plate folds to form the neural groove, and the lips of the groove fuse to form the neural tube, which become the spinal canal and cerebral ventricles, while the swellings at the end of the tube become the forebrain, midbrain, and the24th day after conception. By the end of 7 weeks the embryo is a "fetus". neural crest, dorsal to neural tube, formed form cells that differentiate from tube as its being formed. these cells become neurone and glial cells of peripheral nervous systems. the brain is almost a complete replica in 100 days. Prenatal Neuronal Development - Induction; begins when part of ectoderm becomes nervous system. since cells are totipotent, they are stem cells. Proliferation time of immense cellular division, occurs once neural tube is formed, also called neurogenesis, since its the beginning of development of neuron and occurs for first 5 months of gestation. Cell migration happens after the first neurons are developed, and continues several weeks after neurogenesis is complete. Once they migrate, they aggregate, which means they move toward other cells that have migrated to similar area to form nervous system structures. after this, axonal dendritic, and synaptic formations occur, aka maturation. The axon(sending end of neurone) forms at the arrival at the appropriate surrounding neurone. a single neurone can grow an axon but it takes two neurone and coordinated effort to create synapse, and the formation of synapses is synaptogenesis, a process carried out through life, but mostly early periods of development. so basically, uhhh.. neurone form axons before they have any other neurone or muscle tissues with which they link, but not all primitive neurone form these bonds. Bonding depends on levels of nerve growth factor, which promotes survival and growth of a neurone. its released by organs with which neurone has begun to form a synapse. if a neurone does not receive nerve growth factor or does not bond correctly to receive factor, it will begin the preprogrammed process of nerve cell death, also called apoptosis, and degeneration after a certain time. after this death, the space left on the postsynaptic membrane is filled by sprouting axons of living neurone, leading to a massive rearrangement of synaptic connections. - after 12th week, brain becomes more like adult brain, most noticeable characteristics are ventricles, developed butterfly shape. other subdivisions: telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon. Neuron - building blocks of CNS. Structure - soma; cell body that contains all of the organelles, is where they assemble proteins, generate energy, maintain metabolism. - Nucleus, centre of the neurone containing DNA, the genetic code of a human. each strand of DNA contains chromosomes, which are strands of nucleotides, paired together, forming genes. The remainder of the cell is made up of cytoplasm, internal fluid that holds organelles in place within the cell. Mitochondria also reside in body of cell, site of energy production, aka power plant. Within it are fats, sugars, proteins from food that react with oxygen and produce adenosine triphosphate, energy source for neurone and other cells, consists of adenosine bound to ribose and three phosphate groups. - endoplasmic reticulum, network of tubules within cell that transports synthesized lipids and membrane proteins to other locales. its composed of smooth and rough ER, smooth doesn't have ribosomes, important for synthesis and production of lipids used in carb metabolis, detoxification of cell from drugs and poison. rough has ribosomes, which synthesize proteins. - so proteins are either sent to places where needed or to Mr. Golgi Complex ova here, which basically is a system of membranes that package molecules into vesicles, which are easier at being transported. lysosomes, contain digestive enzymes, provide neurone help in recycling and reusing materials, and microtubules quickly transport materials within neurone. - RNA is like DNA but it has nucleotide base instead of thymine, and phosphate and ribose backbone instead of phosphate and deoxyribose. t carries genetic code from buckles of cell. neurone are covered by a cell membrane composed of lipid bilayer, made of two layers of fat; allows selective permeability to certain substances. its made up of hydrophilic exterior, that attracts water, and interior, which repels water OK WAJIHA THIS SHIT U NEED TO KNOW KNOW NOW. -neuron first receives signal from another neurone at dendrites, which are structures that receive info and send it to the body of the neurone. neurone can have many, that branch to other neurone and act as message receivers, bringing chemical and electrical info. the primary task is to relay an electrical message to the soma, or the body of the neurone. the dendrites are also divided into segments, called orders, named based on their location in relation to the soma. axons are at the opposite end of the cell, they sent info from soma to the presynaptic terminal. signals travelling through axon go in one direction, and usually only one axon per neurone, but they may have many branches, which leave the some distance from the cell body. The axon hillock,is where an impulse/signal is determined to be strong enough to be sent down axon and to next cell, if depolarization and hyperpolzarization reaching it is sufficient to depolarize membrane to a level called threshold of excitation, then action potential occurs, which is the massive momentary reversal of the membrane potential from -70 to +50, synonomous with firing of neuron. The all or nothing principle happens here, so basically signal is strong enough to produce the action potential, or it dissipates. - after this, a brief period called the absolute refractory period occurs, where its impossible of another action potential to take place. the neurone must return to its initial resting potential and reset itself before it can fire again. there's also a relative refractory period, where the neurone can respond to series of impulses that have a greater depolarization charge, this is where the neurone starts to depolarize, but does not reach resting potential; so it needs large stimulus or series of stimuli - myelin sheath, fatty substances that covers the axons and speeds conduction, its produced by oligodendrocytes in CNS and Schwann cels in PNS, Schwann are only cells capable of guiding axonal regeneration. thus axonal regrowth only happens in PNS. Along axon are gaps without myelin, called nodes of Ranvier, which also help in transmission and allow impulse to skip or jump along length of axon, the electrical movement here is saltatory conduction. At the end of the axon is a gap between neurone, called a synapse, junction across which nerve impulse passes from axon terminal to a neurone, muscle cell, or gland. - at the end of axon projecting on synapse is the synaptic vesicles, which store neurotransmitters, and release them into the synapse when the nerve impulse reaches the synapse. Neurotransmitters are the proteins packaged and stored by Golgi bodies in vesicles infused by microtubules to gather at terminal ends of axon. they gather and await on action potential, and often neurotransmitters are next to active zones, areas of protein accumulation in membrane that allow vesicles to deposit contents into the first only info is passed through dendrites, passed to soma and down axon to synaptic vesicle, electrical, but when neuropterans is released its chemical, so the process is now electrochemical. - Otto Loewi and henry Dale discovered neurotransmitters. 2 categories; excitatory; increase likelihood of action potential in postsynaptic neuron; glutamate is most frequent inhibitory; decreases likelihood of action potential in postsynaptic neuron; GABA is most frequent - process of neurotransmitter release is exocytosis, small ones, when excited by action potentials, open voltage-gated calcium channels, which are released as pulses each time in an action potential triggers influx of calcium ions. Peptide neurotransmitters, released in response to increase of Calcium, and then neuropterans sent signal by binding to receptors in postynaptic membrane. Each receptor is a protein that has binding sites for certain neurotransmitters. A molecule that binds to another is called a ligand. - Ionotropic receptors, associated with lingand-activated ion channels, opens immediately, producing a postsynaptic potential. - Metabotropic receptors; associated with signal proteins and G proteins, more prevalent than ionotropic and efforts are slower, longer lasting, more diffuse, more varied. Metabotropic receptor attached to portion of signal protein outside neurone, G protein is attached to portion inside. - Autoreceptors, neurotransmitter receptors located in presynaptic cell, control neuropterans release by presynaptic axon. they regulate and monitor amount of neurotransmitters ion the synapse, which is important in maintaing proper bodily homeostasis and function. When neurotransmitter has been released something needs to happen to prevent it from remaining acive in synapse, bc accumulating ones could lead to danger and problems, like too much dopamine in synapse can trigger delusions, hallucinations, schizo signs. - Reuptake, return of excess neurotransmitter into presynaptic axon, like a vacuum cleaner. - Degradation, neuropterans are broken apart within synapse by enzyme. Glial Cells -thought to be supportive of neuron's functioning. 4 types; oligodendrocytes; form myelin within central nervous system. Schwann cels; form myelin in peripheral nervous system. A strocytesl largest glial cells, functions like passage of chemicals from blood into CNS. Microglia; work by removing cellular debris inc axes of injury or disease. CNS: Cortical Structures - right hemisphere controls left side of body, and vice versa. - brain inside skull for protection, and covered by laters of meninges. - 4 layers: dura mater, arachnoid layer, subarachnoid space, (CSF here, but its also in central canal of spinal cord and cerebral ventricles, and pia mater; closest to brain. - central canal goes from spin cord, central ventricles are 4 large closes in brain giving it characteristic butterfly shape on brain scan. two lateral ventricles, third ventricle, and fourth, connected to one another, and to the central canal and subarachnoid spaces. - CSF produced by group of capillaries, called chorioid plexus, inside ventricles. The excess CSF flows from ventricles around superior sagittal crest, and drains to blood filled space which run throughout dura mater, then into large jugular veins of neck. - blood-brain barrier, group of compacted cells so tightly bound together they keep toxic substances out of brain. different from blood cells in other parts of body which are not as tightly packed, do not form any kind of potectie brier against foreign substances. it basically doesnt let protein and large molecules into brain, but few exceptions like glucose and oxygen. sex hormones are allowed passage in some areas tho. The Brain - telencephalon has cerebral hemisphere and 4 divisions, termed brain stem. - cerebral cortex; convoluted surface later of fray matter of cerebrum, controls coordination of sensory and motor information. Large furrows, called fissures, and small ones called sulci, and ridges between them are gyro, they all give it appearance of a topographical map. largest gyro include pre central gyrus, contains motor cortex, postcentra gyrus; including somatosensory enter, and superior temporal gyrusl contains auditory cortex. - corpus callosum; band of neural fivers that allows right and left hemisphere of brain to communicate; early treatment of epilepsy was to sever this area, stopping neural activity from one hemisphere to the other and also stopping communication. - two different cortical neurons; pyramidal, resemble pyramids, large multiple, large dendrite - stellate neurons; star shaped and short, either few or no axons present. Lobes of the Brain - frontal lobe; in front of brain, responsible for higher order cognitive abilities, thinking, reasoning, planning, language. area that a separates us from other animals. - occipital lobes; most specialized in functioning; back of brain, opposite to frontal, important for vision. Optic chiasma, some of the axons of optic nerve cross over to other side of brain, or decussate. the axons on the nasal side are those that cross to opposite side of brain. Decussation allows each eye to view part of both the right and left visual fields, which is important in case of accident, that has loss of vision. - temporal lobes; side of cortex near temples. involved with processing of information through hearing, left process auditory info for speech, Wernicke's area i here. Right process auditory info in form of tones, music. - Parietal lobes, top of brain, association cortex. responsible for spatial orientation, visual perception, speech, pain sensation. important with how we interact with people, place things, etc. they integral info from all other the sense, leas localized of four lobes. Other Cortical Structures - hippocampus; responsible for memory functions. in cortex, contains 3 layers. its more in limbic system; control motivated behaviours, feeding, sexual behaviour. which is related to emotional behavioural structures here are mamllary bodies, amygdala, fornix, cingulate cortex, septum, in addition t hippocampus. maxillary bodies, relay centre for info going to amydala and hippocampus, and areas most affected by alcohol use, connected with autism. - amygdala carries signals from hippo to mamillar bodies, implicated in emotion - fornix C shaped bundle of axons in brain, carries signals from hippo to mamil. - cingular cortex regulates blood pressure, heart rate, rational cognitive functions. - septum, thin membrane forms medial wall of lateral ventricle, aka septum lucidum. - basal ganglia; contained within telencephalon, include amygdala, caudate nucleus, putamen, globes, pallid us. functions in voluntary motor behaviour. amygdala is her took, its very active in moments that minds need to differentiate emotional response. - caudate nucleus, partially responsible for body movement and coordination - putament reinforcement earning - global pallid us, relays info from other nuclei to thalamus; major relay station for sensory info, all senses except smell, send info through here. once its her, goes to appropriate areas of cortex. - hypothalamus; regulates release of hormones by pituitary gland, regulates temperature within body, fluid intake. and secual behaviour and foooood. - pituitary gland; releases hormones that stimulate other parts of body. -midbrain has 2 divisons - tectum on topmost of mesencephalon, contains inferior colliculi, function with auditory info and superior colliculi, visual function. - tegmentum; contains reticular activating system; set of structures that are related to arousal and alertness. - also has periaqueductal brat, pain reducing effects of certain drugs, - substantial nigra; laye of large pigmented nerve cells, proceed dopamine and whose destruction associated with parkinson' disease. - red nucleus, large well defined, elongated cell mass, receive projection from contrlateral alf of cerebellum, receives additional projections from ipsilateraal motor cortex. - met encephalon; ascending and descending facts, parts of reticular formation. contains: - pons; estructure that relays info from cerebellum to cerebral cortex. control sleeping, autonomic functions - cerebellum; back of brain, involved with movement, coordination, posture, often referred as "little brain: - my encephalon; medulla, connected to spinal cord. composed of tracts ascending/descening from brain. nuclei here regulate respiration and cardiovascular functioning. PNS - located outside of brain and the spinal cord, two divisions. - somatic nervous system; peripheral nerves that send sensory info to central nervous ystem and motor nerves that project to skeletal muscle. composed of afferent nerves, that carry info from eyes, skin, ears to CNS from senses. and also contains efferent nerves, carry motor signals aaay from CNS - autonomic nervous system; regulates body's internal environment, part of PNS - contains efferent neurone that carry motor signals from CNS to internal organs. there are 2 types of these nerves. sympathetic nerves, do the flight or fight. has ffect opposite of parasympathetic nerves or nervous system. parasympathetic nerves, one of two systems within ANS, calming and opposite of SNS. associated with state of relaxation and secual arousal. Spinal Cord -resides in central canal, filled with CSF -made of 2 areas dilenated by inner H shaped core of bray matter, surrounding area of white matter. the tray matter, composed of cell nobodies, unmyelinated interneurons, white, composed of myelinated areas, give wjhite colour. dorsal horns at fray; ventral at ventral gray. - axons joined to spinal cord bia dorsal or ventral root. dorsal root axons sensory afferent, cell bodies group together outside cord to form dorsal root ganglia. bring sensory info to spinal cord or brain. - ventral, motor, efferent neurons, extend axons outside of CNS, directly indirectly control muscles. CHAPTER 3: NEURODEGENERATIVE DISORDERS - neurodegenerative disorders- involve progressive loss of function or destruction of neurone or various structures of the brain. they can be acquired disorders, which are caused by an accident, insult, or disease process coming from source outside the cortex. it's important to understand clinically presented symptoms bc dissimilar difficulties present themselves with similar symptomology, like distinction between dementia and depression, as bot present many cases, loss of neurones is not repairable, and loss of abilities is permanent. Cortical Dementias - damage within cerebral cortex, leads to symptoms of dementia. damage includes memory, reasoning, ability to abstract thought, - 3 stages that fall into dementia: - behaviours that may deviate from norm for individual, like small changes in personality or memory lapses noticed by others. - individual notices memory problems, tries to conceal them from others, confabulation occurs, and they become lost/wander. Sundowning, worsening of symptoms as day progresses, happens here. - serious cognitive deterioration, in a edition to problems associated with self care, at this point working with physicians. patients can't dress, toilet, or feed themselves, but symptoms vary. - most frequent cause of death for patients with dementia is pneumonia. Alzheimer's Type Dementia - characterized by neurofibrillary tangles and amyloid plaques, diagnosis cannot be made until autopsy but is termed Alzheimer's type based on behavioural symptoms. Tangles are made from tau protein; (protein that researchers believe result from abnormal phhosphorylatin;) tangles of dead tissue in brain. amyloid plaques are deposits of aluminum silicate and amyloid peptides that cause loss of neurone and vascular damage. plaques and tangles appear in normal people and in other degenerative diseases, but in alzheimers there's a lot and a specific area they al gravitate towards. - another common feature is loss of neurone in temporal area, leading to changes in anatomical structures - having first degree relative with it, doubles our changes of acquiring it. - 3 other risk factors: -age - gene for protein apolipoprotein E (Apo E) on chromosome 19, helps carry phopholipids and cholesterol within body. it has 3 types, E4 allele, linked with Alzheimers. - Down syndrome; most frequent cause of mental retardation, caused by trisomy on chromosome 21. - traumatic braina injury is a suspected cause, but its only if its very serious, may result to it. another theory s that menopause women can get it due to low estrogen, but that relates with educational level and SES, bc more educated ones will consult medical advise of symptoms. - most distinguishing cognitive features are severe verbal memory difficulties, all stages of memory; endogeny, storage, and retrieval.beginning in first stage. - treatment can be drinking ed wine, which contains antioxidants with protective effect. there also meds that stop development of amyloid plaques, and that keep tau in normal form. treatment for cognitive defiticits usually with anti cholinesterase inhibitors, enhance cholinergic
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