EXAM ONE STUDY QUESTIONS SENSATION AND PERCEPTION Chapter One Introduction 1 Generally speaking what is the difference between sensation and perception Sensation detection of some energy in the physical world Perception Interpretation of that sensation Both depend on biological events Perception is based in part on context what we perceive is not based only on our sense organs but also on past experience and current circumstances 2 What is transduction What types of cells are responsible for it The conversion of some physical energy in the world photons or sound waves for example into something that can be interpreted neural activity 3 What is psychophysics The study of the relationship between physical properties of the world and our psychological perception of these properties The relationship between sensation and perception 4 How does the statement you can never step in the same river twice pertain to sensation and perception No man ever steps in the same river twice for it s not the same river and he s not the same man We are constantly changing as is perception Perception depends on the physical energy that causes the sensation and on the perceiver himself No two similar experiences are identical because the second time around you have the benefit of the first experience The perceiver and the world is always changing the same event happening twice will not be perceived in exactly the same way 5 What is adaptation Adaptation our sense are especially tuned to changes things that remain the same are often missed When things don t change we adapt to them Chapter One Neurons and Neurophysiology 1 What are the parts of a neuron Could you label those parts of a neuron Could you draw label a neuron Soma or cell body contains nucleus and DNA Dendrites receive info and contain proteins Axon sends out info in form of electrical currents Myelin sheath fatty protein made by glial cells Nodes of ranvier Terminal buttons at the end of an axon store neurotransmitters that are released after action potential 2 What is a synapse Terms presynaptic postsynaptic synaptic gap ie synaptic cleft Synapse where two cells meet the junction between neurons that permits information transfer Presynaptic cell that conducts an AP from soma to terminals Postsynaptic cell that receives NT via dendrites Synaptic gap cleft neurotransmitters and receptors 3 What are the 3 main types of neurons Multipolar typical Bipolar Unipolar 4 What are the different types of glia What are their specific functions Schwann cells myelin in the PNS Oligodendrocytes myelin in the CNS Microglia respond to injury disease Radial glial guide cell and axon migration during development type of astrocyte Astrocytes structural support BBB transfer of nutrients from capillaries to neurons surround synapses regulate ion concentration form dense scars etc 5 In general what is different between glia and neurons Glial cells do not transmit info over long distances Glial cells exchange chemicals with neurons Neurons differ in their shape complex morphology and they are 6 How can you connect neurons What would be the functional significance of postmitotic such connections 1 1 relay Many 1 gain complexity 1 Many arousal 7 What is the difference between an inhibitory neuron and an excitatory neuron Excitatory neuron Neurotransmitter that excites the postsynaptic cell like glutamate depolarization more likely to have AP Inhibitory neuron Neurotransmitter that inhibits postsynaptic cell like GABA hyperpolarization less likely to have action potential Modulatory neurotransmitter that excites or inhibits postsynaptic cell depending on the receptor like dopamine 8 What is a neurotransmitter A chemical released by the communicating neuron to the receiving neuron either excites or inhibits the receiving neuron A chemical substance used in neuronal communication at synapses Release caused by action potential 9 What are the parts of a synapse What is the presynaptic cell and what is the postsynaptic cell Presynaptic cell is the axon terminal releasing info Postsynaptic cell is the dendrites receiving the information receiving info 10 Where does the action potential occur Generates at axon hillock movement of ions down an axon Action potential the brief electrical impulse that provides the basis for conduction of information along an axon 11 What ions are involved Na K Cl 12 Understand the terms Polarization Depolarization Hyperpolarization Polarization Depolarization neuron becomes less negative more positive Hyperpolarization neuron becomes more negative Na enters the cell Cl enters the cell K leaves the cell 13 What forces act on the ions Electrical activity entropy Concentration gradient ions flow from high to low concentration Electrical gradient ions flow to areas of opposite charge Opened by changes in the membrane potential for both sodium and potassium Those from sodium are more sensitive potassium channels require a greater change in membrane potential before they open 14 What is a voltage gated channel Channels in the membrane of an axon that ions flow through 15 Starting w threshold being reached at the axon hillock what happens during an action potential When threshold 50mV is reached at the axon hillock voltage gated channels open up Na rushes into the cell cell becomes depolarized Voltage gated potassium channels open up and voltage gated sodium channels close K rushes out of cell cell becomes hyperpolarized Voltage gated K close that part of the membrane is back to 70mV 16 Think about the size and rate of action potentials Which one can vary and which is constant The size of each action potential is always constant The rate of firing is limited by the refractory period 17 What is the role of calcium When the action potential reaches the axon terminal it opens voltage gated calcium channels Ca enters the terminal and allows synaptic vesicles full of neurotransmitters to bind to the terminal membrane and release the neurotransmitter into the synaptic cleft 18 What is the function of myelin What are nodes of Ranvier and what do they have that myelinated segments of the axon do not have Myelin a fatty protein put on by glial cells speeds up action potential and saves energy Nodes of Ranvier un myelinated segment of axon between myelinated segments action potential is regenerated here 19 What is an IPSP EPSP What is the big difference b t an action potential and an EPSP EPSP excitatory post synaptic potential a depolarization in the
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