Question

Explain the steps release of neurotransmitter from the synaptic bulb and how that leads t a graded potential in the postsynaptic neuron.

Answer 1

Synaptic transmission.

Communication between two neurons occurs through specialized structure called synapse.Synapse is the area where two neurons come closer to one another and able to pass communication . They are not actually connected separated by space called synaptic cleft.Synaptic bulb is the end bulged region of the presynaptic membrane.

The neuron where signal is initiated is called pre synaptic neuron.And the neuron that receives signals are called post synaptic neuron.In the pre synaptic neuron there are chemicals called neurotransmitters which are packed in small sacs called vesicles. Each vesicle contains thousands of neurotransmitters.when the presynaptic membrane excited by action potential the vesicles in the synaptic bulb fuse with presynaptic membrane and release neurotransmitter into the synaptic cleft.The neurotransmitter in the synaptic cleft fuses with the post synaptic membrane receptors.They bind to the receptors and cause action in the post synaptic membrane.

Neurotransmitters can be either excitatory or inhibitory depends on the neurotransmitter relesed.Graded potential that makes the membrane potential less negative or more positive.So the excitatory neurotransmitter causes graded potential in post synaptic membrane . Excitatory neurotransmitters include GABA, glutamate etc.These excitatory neurotransmitters causes graded potential bin the post synaptic membrane.