Axon Terminal and Presynaptic Cell

Anatomy and Functions

The Axon Terminal

The axon terminal, also known as the presynaptic terminal or synaptic knob, is the specialized structure at the end of an axon that transmits electrical impulses to another neuron. It consists of a bulb-shaped swelling filled with synaptic vesicles, which contain neurotransmitters.

The Presynaptic Cell

The cell to which the axon terminal belongs sending cell is called the presynaptic cell. This cell synthesizes and releases neurotransmitters, which are chemical messengers that transmit signals across the synaptic cleft (the gap between neurons).

Synaptic Transmission

When an electrical impulse reaches the axon terminal, it triggers the release of neurotransmitters from synaptic vesicles. These neurotransmitters diffuse across the synaptic cleft and bind to receptors on the postsynaptic cell, which is the receiving cell.

The binding of neurotransmitters to postsynaptic receptors can either excite or inhibit the postsynaptic cell, depending on the type of neurotransmitter and receptor. This process of synaptic transmission underlies all neural communication in the nervous system.

Conclusion

The axon terminal and presynaptic cell play a crucial role in the transmission of information within the nervous system. Their coordinated activity enables communication between neurons, which is essential for sensory perception, motor control, and higher-order cognitive functions. Understanding the mechanisms of synaptic transmission is critical for comprehending the function and malfunctions of the nervous system.