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Control TheoryRegulationNSWeek 2 ShitSheet5Sheet1allostatic regulation:Bernard, ClaudeCanon, Walter Bclosed loop cyberneticsdelayemergencefeed forwardgainhomeostasisnegative feedbackopen looposcillationpositive feedbackregulatory cascadeset pointfeed back loop: one input, one output and a response; output affects feedback signal; continuous regulation"science" control communications in animal and machine; norbert weiner; 1948usually detectable in a feedback system; depends on anatomy or processingexpresses intnesity or magnuitude of effector action; "amount of change from stimulus to effector/response" regulation; tendency of a system to maintian internal stabilityinput-action-output; no self regulation; system has control but its is not automatic; only response feedback keeps response loop going making change greaterwave of stimuli passes over chain of intermediates; initial trigger of an inactive precursor to an active form desired target value for a parameter; oscillations occur around set pointhomeostasis; set point can vary depending on conditions (allostatic = changed conditions) "the sum of everything portraying homeostasis"1865; "regulation of internal enviorment in the body within a relatively narrow range", first to suggest the idea we now call homeostasis1929; coined "homeostasis" ; four postulates: 1. Role of nervous system and how it preserves the "fitness" of the internal enviorment (blood preassure, bodyemp) 2. tonic regulation: wide range of response in the body with one control (blood vessel diameter) 3. Antagonistic control: (sympathetic vs parasympathetic) percise control; opposing affects 4. chemical signals have different effect in different tissue; receptors (epinephrine affects everyones heart differently)bases off simple functional elements + large number of elements = new complex macro behavior ; unpredictable yet derived from the behavior of simple elements; bottom up controlopen loop; starts a response before a stimulus does; involves learning; (prediction) ; reponse opposite direction of the change; closed loop; oppose change and return to set point; homeostatic ; operate in a narrow rangelong delay; high gain; movement of a parameter around a desired range/setpoint; (negative feedback)homeostasissee. Negative or Positive feedbacknervoussystem, ant hillpH, body temp, etc.shivering,see feed forwardprotein kinase cascade98.6 (normal body)present in all physiological systems; can be large or smalpavlovs dog; salivating before eating; using rate of change information to predict changing conditions; HCG and pre-pregnancygently blowing on the fur of an animal cause large actionship steerer (long delay in turning=large response) ; body temp. ; milk secretion due to increased suckling; not being able to stop in the middle of peeingattractorcell bodyendocrineparacrinephase space diagramautocrine self-regulation reflexpoint in "chaos system" that system wants to go to; zero momentum, zero velocitynucleus and much of the synthetic apparatus of the cell; includes nucleus,rough ER, golgi complex, mitochondrialong distance regulation/signaling; uses chemical hormones that go into bloodstreamnon-linear chaotic systems1960's; discovery of new manifestations of complex, nonlinear systems, need new graphical/mathmatical techniques to analyze; small changes in initial conditions lead to big changes in system functionlocal chemical signaling; effects cells in immediate vicinityposition vs. momemtum plot; does not display time values for nonlinear systems; tell velocity, patterns that you cant see on traditional time series graphrequires sensory input and integrating center and effector functions; smallest unit of regulatory functionweather; butterfly effectdodging a ball by duckingpendulums eventually go to endpoint; big part of cell (not dendrite or extremities)growth hormones during pubertydiffusion, histamine diffuses into capiliaries at point of injuryastrocytesglial cells non-neuronal, support cells of the CNS; regulate and protect the nervous systemCNSPNSOgliodendrocytes form myelin sheaths in the CNS; affects several axonsSchwann Cells form myelin sheaths in the PNS; only effect one neuronaxonaxon terminalbipolarcentralization centerline of the body; more complex regulation by NS, common in vertabrae cephalization leading towards the head, aka head centrilzationdendritesdorsal root gangliaganglion cluster of nerve cell bodies in PNS, may carry out simple processinginterneuronmotor neuronsmultipolar nueron many dendrites, 1 axonmyelin layers of cell membrane that insulate axons, speed up signals along axonnerve netpost synaptic after the synapse, contains receptor proteins on surface pre synapticpsuedounipolarreceptorsensory neuronsynapse narrow gap specialized for communication between neuronssynaptic vessicles small secretory vessicles that release neurotransmitters into the synapsestar shaped; part of blood brain barrier system; contact with both neurons and blood vessels; most abundant type of glial cellbrain/spinal cord; more specialized, complex regulation; complexity, centralizationeverything else/extremities; some regulation in the parts that are close to CNS, only regulation in the PNS is in the gangliaextension of neuron that carries signal to target cell; each neuron has ONE axon; has branches ("collaterals") along it length, can be covered myelin sheathsdistal end of a neuron where a neurotransmitter is released in the synapse; signal is being released from this point; presynapticneuron have two extensions: 1 dendrite/1 axon; "primitive"; first neuron in development, rare in adult - many become pseudounipolar. thin branched extension that receive and transport incoming info to an integrating region within the neuron; usually multiple and highly branched concentrated collection of cell neurons outside the CNS on the dorsal root before the spinal cord, no synapses, no processing of information; contains cell bodies of psuedounipolor sensory nuerons, afferent signal integrate multiple inputs, generate other patterns, many functions, everything that’s not sensory/motor nuerons, CNSsend signal from internueron to a response target (muscle or gland), efferant pathwayprimitve arangements of neurons, little or no spacial organization, little or no specialization of neurons, potentially many pathways of activity through the net. (only bipolar)before the synapse, contains nuerotransmitters to be send across the synapse, axon

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DREXEL BIO 203 - Notes

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