Abhishek Pandey posted an Question
April 20, 2021 • 20:54 pm 30 points
  • CSIR NET
  • Life Sciences

Life se iences-1s ( strtation mat hysiclogy) resting membrene potentiat depolarieaos epotertsstion resing meeeden poterse ppening ot ha hanpes 30 closing of na

Life Se iences-1s ( Strtation mat hysiclogy) Resting Membrene Potentiat DepolariEaos epotertsstion Resing Meeeden Poterse Ppening ot Ha hanpes 30 Closing of Na channels and 99enina of K cherinels Closing of K channetas -50 -90 Time Fig. Graphical Representation of Membrane Potential Changes and Associated Events During Action Potential Generation Action Potential Propagation Upon generation of an action potential in any part of the neuron the increased permeability of Na in a localized area of the neuron leads to the development of a local circuit in adjacent regions of the membrane. The positive electrical charges are carried by the inward-diffusion of Na through the depolarized membrane and then for some millimeters in both directions along the axis of the axon. This leads to the increase of voltage in the adjacent 1 to 3 millimeters inside the myeli fiber to above a certain threshold level that leads to the generation of action potential in the adjacent regions which gradually spreads throughout the nerve cell through successive opening of Na channels. d Propagation of an action potential does not happen in an unidirectional fashion but throughout All or Nothing Principle: Upon action potential generation in a particular region of a cell the depolarization process travels throughout the membrane if all conditions are favorable or it does not travel if conditions are not right. This is called the all or nothing principle. the entirety of the cell whose entire membrane becomes depolarized. exchange of ions from the interior of the cell with the environment and such exchange can only occur through the nodes of Ranvier. Therefore, generation of action potential happens only at these nodes thus the action potential jumps from node to node. This mode of nenve impulse conduction is termed as saltatory conduction and greatly increases the speed Saltatory Conduction in Myelinated Neurons: The myelin sheath prevents the free The velocity of nerve impulse conduction is about 0.25 m/sec in non-myelinated fibers and 100 m/sec in myelinated fibers. of nerve impulse conduction by at least 5 to 50 folds. 33 an405800

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    Krishan k jakhad best-answer

    The nerve fibres are either depolarized or they are said to be in the action potential. The action potential travelling along the membrane is called the nerve impulse. It is around + 30 mV. The sodium-potassium pump starts to operate once the action potential is completed. As a result, the axon membrane will obtain a resting potential by repolarization. Now the process takes place in reverse order. It is a reversal of the process that has taken place during an action potential. Here, potassium ions will be rushed inside and sodium ions will be rushed outside. Impulse would not be transmitted through the nerve fibre during the refractory period.

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