QS Study

Synapse is a functional connection between two neurons where one neuron ends and another neuron begins. It is a particular junction at which a neuron cell communicates with a target cell. At a synapse, one neuron sends a message to a target neuron – another cell. There is no anatomical continuity between two neurons involved in the formation of the synapse.

Structurally the synapse has three pasts.

  1. Presynaptic Terminal:

This is the terminal end of axon called axon telodendria or terminal button. It contains numerous synaptic vesicles containing neurotransmitters and mitochondria which supply energy for synaptic activity.

Fig: Structure of Synapse

  1. Postsynaptic membrane:

It is the membrane of the postsynaptic neuron or target organ. It contains highly selective receptors for the neurotransmitter. The synaptic membrane of the post-synaptic cell is usually on the dendrite of the next neuron. This absorbs neurotransmitters into the post-synaptic neuron.

  1. Synaptic cleft:

It is a narrow fluid-filled gap between pre and postsynaptic membrane (200 A0). It contains Ca++ ions and an enzyme called cholinesterase for the destruction of acetylcholine. This space is filled with an extracellular matrix of proteins that mainly acts to hold the two neurons together.