4. Transmission of the excitation (inhibition) from one excitable cell to another. Synapses -types of synapses. Chemical synapses. Neurotransmitters and modulators. Postsynaptic potentials. Summation of the postsynaptic potentials.
Topic 4 of 69 in the MU Plovdiv syllabus for Human Physiology (Dental Medicine, Year 2). The free AceMed note covers it in 2 sections, about 1,565 words (11 min of reading), with 27 flashcards.
In this note
Introduction
Synthesis and Storage of Neurotransmitters
Introduction
Synapse is the junction between two cells where communication between the cells takes place.
Each synapse consists of the:
Presynaptic membrane – membrane of the terminal button of the nerve fiber
Postsynaptic membrane – membrane of the target cell
Synaptic cleft – a gap between the presynaptic and postsynaptic membranes
A synapse is a gap that is present between two neurones. Action potentials are propagated across the synapse by synaptic transmission, also known as neurotransmission. The neurone that sends the signal is the presynaptic neurone, whilst the postsynaptic neurone receives the signal.
Neurotransmission starts with the release of a readily available neurotransmitter from the presynaptic neurone, followed by its diffusion and binding to the postsynaptic receptors. Then the postsynaptic cell responds according to the neurotransmitter. Following this, the neurotransmitter is removed or deactivated, allowing the entire cycle to occur again.
