Synapse with serotonin and melatonin
The picture shows a synapse. Synapses are the contacts between nerves or nerves and other cells. There are electrical and chemical synapses. The one on the picture is a chemical synapse. The upper part is the terminal axon of a nerve cell, in which vesicles filled with neurotransmitters, in this case serotonin, are located. When a stimulus arrives, the vesicles fuse with the membrane, the neurotransmitters are released into the synaptic cleft, which is so small that they end up at the receptors of the postsynaptic density of the dendrites of the following cell. This way they cause a signal. Shortage of serotonin causes depression or anxiety disorders. Melatonin is made out of serotonin in the pineal gland. The hormone melatonin regulates the circadian rhythm.
