Synapses are small gaps at the ends of neurons that allow the transfer of signals from the presynaptic cell to the postsynaptic cell. Synapses consist of chemical synapses and electrical synapses, each of which has a different way of working.
What are synapses?
As part of the central nervous system, synapses are small gaps at the ends of neurons that are places where nerve cells connect with other nerve cells. Synapses allow signals to pass from one neuron to the next. The term synapses comes from the Greek word meaning “conjunction.”
Synapses can also be referred to as nerve connections. This is where the transmission of electrical nerve impulses between two nerve cells (neurons with each other) or between neurons with muscle or gland cells. The synaptic connection between neurons and muscle cells is called the neuromuscular junctions.
Synapses are formed by axon terminals (ends of nerve tubes) that swell and form button-like structures. The axon terminals are separated from adjacent neuronal fibers by microscopic spaces called the synaptic cleft.
Classification of synapse
Based on neuronal attachments, synapses can be classified into the following types:
- Axodendritic
- Axosomatic
- Axoaxonic
Based on the neurotransmitters and neuroreceptors in neurons, synapses can be classified into the following types:
- Excitatory Ion Channel Synapses
- Inhibitory Ion Channel Synapses
- Non Channel Synapses.
Synapse parts
Neurons have parts called dendrites and axons. Here are each of its functions.
- Dendrites carry information to the cell body. Dendrites will capture stimuli in the form of impulses and send them to the axon.
- Axons take information from the cell body. The axon then sends impulses to other neuronal cells towards the central nerve and produces a response in the form of movement.
Information in the nervous system flows from one neuron to another through synapses that contain small gaps separating the two neurons. The parts of synapses consist of:
- Presynaptic endings contain neurotransmitters, mitochondria, and other cell organelles.
- Postsynaptic endings contain receptor sites for neurotransmitters.
- Synaptic gaps or spaces between the ends of the presynaptic (first neuron) and the postsynaptic (second neurons).
For communication between neurons to occur, electrical impulses must travel down the axon to the axon terminal.
Structure of synapse
This electrical stimulation has been found as a way for these cells to communicate with other cells. Electrical signals are sent to other cells via an axon.
Imagine whispering in the ears of others. While you may be close to the person sending the message, you may not have to physically tap the flow of information. In addition, neurons are not related to stimulation cells.
Instead, they communicate with each other by releasing neurotransmitters or chemical messengers. This neurotransmitter is released from behind the axis and spreads in a small space to the target. Therefore include synapses that are the field of communication:
- Receptors in target cells that bind with neurotransmitters.
- Neurons of the final axis.
- The space between two cells, called the synaptic gap.
There are synaptic vesicles in the synaptic cytoplasm. When the pulse reaches the end of the neuron, the vesicle moves, then merges against a pre-synaptic membrane and releases acetylcholine.
Acetylcholine acts on synapses and then binds to receptors on the postsynaptic membrane. The release of acetylcholine into the receptor causes impulses towards subsequent nerve cells. The acetylcholinesterase enzyme can indicate that the presence of acetylcholine has been completed.
Synapse Functions
There are various types of functions in these synapses, including the following:
- As a provider in a connection between neurons that allows an impulse to flow between neurons
- Divide an impulse into neurons.
- Stimulates muscle cells.
- Manage neuron transmission.
- Play the role of creating memories in humans or animals.
Transmission of neuronal signals between related neurons is not an easy process. Nerve impulses must stimulate synaptic vesicles in order to integrate into the axial membrane. Removal of synaptic vesicles guarantees the release of neurotransmitters through exostosis.
Chemical messages or neurotransmitters can then send nerve signals from the presynaptic terminal outside the synaptic column. Once released, it binds to specific cell receptors of postsynaptic neurons or target cells. The effect of neurotransmitters can be prevention or excitation, as a result of which bound neurons can be stimulated or broken down.
Here we can use reference neurotransmitters as key receptors and cells as keys. For this reason, neurotransmitters act as keys that can open and close key cells or receptors. Neurotransmitters, which bind specifically to cell receptors, initiate further movement of neuronal signals.
