 New students in this module, we shall discuss the methods of transmission of signals in the nervous system The neuronal signals are transmitted in the nervous system in two forms the first method is the graded electrotonically conducted potentials and the second form is the in the form of action potentials New students a signal is coded alternately in these two forms that is graded potentials and action potentials The graded potentials are produced for short-distance conduction at the sensory and post-synaptic membranes while action potentials are generated for long-distance conduction along the axons this coding also involves interconversion of electrical and chemical methods at synapses We shall take an example in which a stimulus is received by a receptor organ at its sensory neuron as a result a signal is generated which is transmitted through the neuron into the other components of nervous system when a stimulus is received at the receptor endings of sensory neuron a depolarization that is a change in membrane potential occurs this change happens in proportion to this strength of the stimulus This potential change at the receptor side is known as receptor potential this receptor potential is graded potential because it varies in a continuous fashion dear students the time course and amplitude of a receptor potential are closely related to the time course and intensity of the stimulus so the receptor potential is an Electrical neuronal analog of the stimulus actually J2 receptor potential Hey, yeah stimulus key a electric copy. Hey after receiving the signal The signal spreads away from the receptor site passively through Electro tonic conduction to the cell body part of the neuron however This signal decays over a relatively shorter distance The decay happens because of the resistance of cytoplasm faced in the cell body as well as Due to the reason that this part of the neuron does not contain voltage-gated ion channels So action potentials cannot be Propagated are produced in this part of the sensory neuron or distant transmission Agar a signal go to the cell Lumbay fast litak transmit karna hair. So who's Kelly a graded potentials coffee? It's Kelly a regenerative action potentials produce karna hota which are produced at the Spike initiating zone that is the axon hillock Exon hillock contains voltage-gated ion channels or yeah, yeah, okay. Yeah, upper action potentials Initiate, oh, sir. Hey, these action potentials can conduct signals Without decrement for long distances When the signal reaches the axon terminals It is transformed from electrically encoded signals into chemical signals in the form of neuro transmitter molecules This chemical signal is then transmitted across the synapse to the next neuron When the neurotransmitter Reaches the next neuron that is the post-synaptic neuron it causes potential change in the post-synaptic cell The change in membrane potential Happens when the chemical signal is converted back into the chemical signal into the electrical signal This membrane potential generated in the post-synaptic neuron is known as post-synaptic potential The post-synaptic signal or post-synaptic potential produces a graded signal That reflects the properties of the original stimulus This process was initiated by the receptor site and the potential was generated by the receptor The post-synaptic potential is the same as the potential of the receptor which is graded This graded post-synaptic potential again brings the spike-initiating zone of the post-synaptic cell to threshold thereby, triggering an action potential in the post-synaptic cell If we look at it this way, the signal initiated by one cell has been transferred to another cell and during that time, it has moved on to both electrical and chemical forms and in addition to this, the graded and regenerative action potential has been moved on to both patterns Thus, these signals move from the peripheral nervous system to the central nervous system