ABSTRACT
This chapter describes the mechanisms involved in the process of synaptic transmission including inhibitory and excitatory postsynaptic potentials, and temporal and spatial summation. It explores how the parasympathetic nervous system regulates the gastrointestinal system, heart and secretory glands. Neurons are diverse in shape and size. A typical neuron has a cell body with fibre-like processes called dendrites and axons emerging from it. The dendrites are branches that leave the cell body and receive information from adjoining neurons. When a neuron is activated, an electrical impulse called an action potential is generated at the axon hillock and then conducted along the axon. The action potential releases neurotransmitters from the nerve terminal, and these bind to receptors located on target cells, causing a flow of ions across the postsynaptic membrane. Ions can flow across the nerve cell membrane through three types of channels: non-gated, ligand-gated and voltage-gated channels.
