IMG_0129.jpeg

# Generation of EPSP The image describes the process of excitatory postsynaptic potential (EPSP) generation at a synapse. ## Steps 1. **Neurotransmitter is released:** Neurotransmitters are released from vesicles in the presynaptic neuron's synaptic knob into the synaptic cleft. 2. **Chemically...

# Generation of EPSP The image describes the process of excitatory postsynaptic potential (EPSP) generation at a synapse. ## Steps 1. **Neurotransmitter is released:** Neurotransmitters are released from vesicles in the presynaptic neuron's synaptic knob into the synaptic cleft. 2. **Chemically gated cation channels open:** The released neurotransmitters bind to chemically gated cation channels on the postsynaptic neuron's membrane, causing them to open. Sodium ($Na^+$) ions flow into the postsynaptic neuron. 3. **EPSP is established:** The influx of sodium ions causes a local depolarization of the postsynaptic membrane, creating an excitatory postsynaptic potential (EPSP). (See graph) 4. **EPSP moves toward the initial segment:** The EPSP spreads toward the initial segment of the postsynaptic neuron, where it can trigger an action potential if the combined EPSPs reach the threshold level. ## Illustration The image shows a detailed diagram of a synapse, including the presynaptic and postsynaptic neurons, synaptic knob, synaptic cleft, and neurotransmitter release. It also includes a graph showing how the membrane potential changes during the generation of an EPSP. **Graph Description:** The graph plots membrane potential (in millivolts) over time (in milliseconds). It shows the resting membrane potential (RMP) at -70 mV. A stimulus causes a rapid depolarization (EPSP) to a level above the threshold, before returning to the RMP. The threshold is the level at which an action potential is generated.