“All or None law" (Keith Lucas, 1905) : When stimulated, the axon membrane
(= axolemma) does not respond for a moment due to its resistance or threshold to stimulation. However, when its threshold is broKen, the stimulation is conducted through its whole length as a strong impulse. If the stimulation is too weak to break the axon's threshold, impulse is not established, but if the intensity of stimulation is much more than the threshold value, impulse conduction remains normal. Thus, the action potential obeys “all or none law". In other words, impulse conduction is such a triggered phenomenon which, though occurs in a twinkling, like an explosion, but only when it reaches "ignition point" or firing level".
Synapse, A one-way valve : The synapse cannot transmit an impulse in the reverse direction as the dendrites cannot secrete a neurotransmitter. Thus, the synapse acts as a one-way valve, allowing the conduct of impulse from axon to dendron only.
Synaptic delay : Transmission of an impulse across a synapse is slower than its conduction along a neuron. This is because of the time needed for the release of a neurotransmitter, its diffusion through the synaptic cleft, and its action on the postsynaptic membrane. The difference in the rate is called synaptic delay. It amounts. to about half a millisecond at body temperature (37oC).
Synaptic fatigue: Repeated stimulation of the presynaptic Knob may deplete the neurotransmitter, and this may fail to stimulate the postsynaptic membrane. This condition of the synapse is termed synaptic fatigue. It lasts for several seconds during which the neurotransmitter is resynthesized. Synaptic fatigue . is the only fatigue that affects the nervous tissue. Conduction of the nerve impulse along the neurons is not subject to Fatigue
(= axolemma) does not respond for a moment due to its resistance or threshold to stimulation. However, when its threshold is broKen, the stimulation is conducted through its whole length as a strong impulse. If the stimulation is too weak to break the axon's threshold, impulse is not established, but if the intensity of stimulation is much more than the threshold value, impulse conduction remains normal. Thus, the action potential obeys “all or none law". In other words, impulse conduction is such a triggered phenomenon which, though occurs in a twinkling, like an explosion, but only when it reaches "ignition point" or firing level".
Synapse, A one-way valve : The synapse cannot transmit an impulse in the reverse direction as the dendrites cannot secrete a neurotransmitter. Thus, the synapse acts as a one-way valve, allowing the conduct of impulse from axon to dendron only.
Synaptic delay : Transmission of an impulse across a synapse is slower than its conduction along a neuron. This is because of the time needed for the release of a neurotransmitter, its diffusion through the synaptic cleft, and its action on the postsynaptic membrane. The difference in the rate is called synaptic delay. It amounts. to about half a millisecond at body temperature (37oC).
Synaptic fatigue: Repeated stimulation of the presynaptic Knob may deplete the neurotransmitter, and this may fail to stimulate the postsynaptic membrane. This condition of the synapse is termed synaptic fatigue. It lasts for several seconds during which the neurotransmitter is resynthesized. Synaptic fatigue . is the only fatigue that affects the nervous tissue. Conduction of the nerve impulse along the neurons is not subject to Fatigue
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