Synapse neuron is basically electrical devices. There are many channels in the cell membrane (the boundary between the cell inside and outside) that allow the flow of positive or negative ions into and out of the cell.


Usually, the inside of the cell is more negative than outside; neurologists say that the inside is about -70 mV in relation to the outside, or that the potential of the resting cell membrane is -70 mV.


This membrane potential is not static. It keeps going up and down, depending mainly on the input data from the axons of other neurons.

Some input data make the neuronal membrane potential more positive (or less negative, e.g. -70 mV to -65 mV), while others do the opposite.

They are appropriately referred to as excitatory and inhibitory because they promote or inhibit the generation of action potentials (the cause of some stimulatory signals, while others inhibit the fact that different types of neurons release various neurotransmitters, and the neurotransmitter used by the neuron determines its action).


Synapse Neuron

Functional potentials are the basic units of communication between neurons and occur when the sum of all excitation and inhibitory signals causes the potential of the neuron membrane to reach about -50 mV (see graph), the value called the functional potential threshold.


Synapse Neuron


Neuroscientists often define the action potentials as “jumps” or say that the neuron “fired” the spike “or” conquered. “This term is a reference to the shape of the action potential recorded using a sensitive electric current.



Synapse neuron
Synapse neuron



Synapses: how neurons communicate with each other

Neurons talk to each other through synapses. When the action potential reaches the presynaptic terminal, it causes the release of the neurotransmitter from the neuron to the synaptic cleft, a 20-40 nm gap between the presynaptic axon and the postsynaptic dendrite (often the spine).


After passing through the synaptic cleft, the transmitter will attach to the neurotransmitter receptors on the postsynaptic side and depending on the released neurotransmitter (which is dependent on the type of neuron released), the specific positive (e.g. Na +, K +, Ca +) or negative ion (e.g. Cl-) will pass through the channels extending along the membrane.


Synapse neuron can be thought of as transforming an electrical signal (action potential) into a chemical signal in the form of nerve relay release, and then, after binding the relay to the postsynaptic receptor, switching the signal back to the electrical form, just as charged ions flow to or from the postsynaptic neuron.



Concepts and definitions

Axon – A long, thin structure in which functional potentials are generated, the transmission part of the neuron. After initiation, the action potentials move down the axons, causing the release of the neurotransmitter. Dendrite – Receiving part of the neuron.


Dendrites receive synaptic input signals from axons. The sum of dendritic input signals determining whether the neuron will trigger the action potential.

Spinal column – small protrusions occurring on dendrites, which for many synapses constitute the place of post-synaptic contact.



Diaphragm potential synapse neuron

The electric potential in the neuronal cell membrane, which arises due to different distributions of positively and negatively charged ions inside and outside the cell.


The value inside the cell is always determined from the outside. 70 mV means that the interior is 70 mV more negative than the external one (which is 0 mV).


Action potential – Short (~ 1 ms) electrical event usually generated in the axon that signals the neuron as “active”.

The functional potential moves along the length of the axon and causes the release of the neurotransmitter in the synapse.

The potential of the action and the resulting release of the transmitter allows the neurons to communicate with other neurons.


The neurotransmitter – a chemical released from the neuron as a result of the potential.

The neurotransmitter travels through the synapse to stimulate or inhibit the target neuron.

Distinct types of neurons utilize different neurotransmitters and therefore have different effects on their targets. Synapse neuron – A connection between the axon of one neuron and another dendrite through which two neurons communicate.