Psych 202 1st Edition Exam 3 Study Guide Lectures 14 19 Ch 3 Book Notes Neurons are the basic building blocks of the nervous system o They receive and send chemical messages o All neurons have the same basic structure but neurons vary by function and by location in the nervous system Changes in neuron s electrical charge are the basis of an action potential or neural firing o Firing the means of communication within networks of neurons Neurons don t touch they release chemicals neurotransmitters into the synaptic cleft a small gap between the neurons o Neurotransmitters bind with the receptors of postsynaptic neurons thus changing the charge in those neurons o Neurotransmitters effects are halted by reuptake of the neurotransmitters into the presynaptic neurons by enzyme deactivation or by autoreception Human behavior is influenced by genes o Through genes people inherit both physical attributes and personality traits from their parents o Chromosomes are made of genes and the Human Genome Project has mapped the genes that make up humans 23 chromosomes Genes may be dominant or recessive o An organism s genetic constitution is referred to as its genotype o The organism s observable characteristics are referred to as its phenotype o Many characteristics are polygenic An offspring receives half of its chromosomes from mother and half from father o Because so many pairs of the 23 pairs of chromosomes is possible there is tremendous genetic variation in the human species o Mutations resulting from errors in cell division also gave rise to genetic variation Behavioral geneticists examine how genes and environment interact to influence psychological activity and behavior o Twin studies and research on adoptees provide insight into heritability Genes and social contexts interact in ways that influence our observable characteristics o Genetic manipulation has been achieved in mammals such as mice Animal studies using the technique of knocking out genes to determine their effects on behavior and on disease are a valuable tool for understanding genetic influences Ch 4 Book Notes Stimuli reaching the receptors are converted to neural impulses through the process of transduction By studying how people respond to different sensory levels scientists can determine thresholds and perceived change based on signal detection theory o Our sensory systems are tuned to both adapt to constant levels of stimulation and detect changes in our environment Receptors rods and cones in the retina detect different forms of light waves o The lens helps the eye focus the stimulation on the retina for near versus far objects o Color is determined by wavelengths of light which activate certain types of cones by the absorption of wavelengths by objects or by the mixing of wavelengths of light Humans and other animals have a kinesthetic sense ability to judge where one s body and limbs are in space and a vestibular sense ability to judge the direction and intensity of head movements associated with a sense of balance The Gesalt principles of organization account for some of the brain s perceptions of the world o The principles include distinguishing figure and ground the grouping of objects on the basis of proximity and similarity and the perception of best forms o Perception involves two processes bottom up processes sensory information and top down processes expectations about what we will perceive o Researchers have identified brain regions that are specialized for the perception of faces Hits and correct rejections good False alarms and misses bad Rasmussen s Disease Video Clip Moves foot o Brain sends message to certain muscles in foot o They contract and foot moves o The message is transmitted from brain to foot by neurons nerve cells A group of neurons bundled together is called a nerve Each neuron has a long extension called an axon that transmits the message These axons begin in the base of the spinal cord and end at a muscle in the foot Axons are built to conduct electrical messages called action potentials Schwann calls insulate axons to help action potentials electrical messages be transmitted more quickly Electricity is created by a sudden reversal in charge An action potential is simply an electrical current that travels down an axon of a neuron An action potential can only occur when opposite charges exist on two sides of a cell membrane The area outside a neuron s axis is while the area inside the axon is An action potential is a brief reversal of that charge which moves down the axon The fluid in and around all cells is filled with ions Ions very small molecules or atoms with charge Neurons use sodium ions and potassium ions to create membrane polarity When a neuron is resting not transmitting an electrical message Na and K ions move down their concentration gradients through their membrane channels to opposite sides of the membrane Meanwhile a specialized pump located in the membrane maintains the concentration gradient by using energy to force sodium and potassium back to the sides they came from For every 3 Na ions pumped outside the neuron only two K ions are pumped in The number of charges on the outside of the axon is higher than on the inside The difference results in the inside of the axon being negatively charged relative to the outside More positive ions remain outside cell than inside the cell The outside of the neuron is positive when compared to the inside AKA resting potential Na outside K inside o First step in sending a signal action potential depolarization When the inside of the cell becomes positive Repolarization is the returning of the cell to the resting potential the inside of the cell will become more negative o In order to function neurons must maintain a difference in electrical charge across their membranes Voltage gated membrane channels and Na K pumps redistribute ions during action potentials and when the neuron is at rest A rapid brief electrical current pulses down the length of an axon to transmit a nerve impulse This message is carried extraordinary distances in some long axons The message is carried from the brain to this foot in what we perceive as an instant Sack s Cases o Ch 5 Hands Cerebral Palsy and blind Needed to construct a gnostic system that she never had in the first place to discover her hands The integration is in the action Her birth as a motor individual picked up a bagel and ate it Now a perceptual individual Intelligence had nothing to do with it