Cnidarians have primitive nervous systems that have nerve cells distributed throughout their body. These nerve cells act as a motor and sensory neurons and chemical peptides are very influential signal molecules that have excitatory and inhibitory functions. Coral nervous systems are relatively simple but are very important for tentacle movement, digestion, and excreting waste. 

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Nerve Net

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Corals have no brains but have a nerve net that goes from the mouth to tentacles. Nerve nets can amazingly sense temperature, the salinity of water, oxygen concentration, gravity, ocean currents, and more. Cnidarian motor systems need fast impulse transmissions in circular and radial directions to allow coordination for muscle cells. Fast transmission is important for the efficient release of water from the bell of the body. The nerve net that is a two-dimensional muscle sheet, is the most ideal system for it is non-polarized and is a diffuse conducting system that supports swim musculature. There are synaptic sites that are by neurites to encourage neuromuscular action. Being non-polarized neurons and the special organization of individual neurons makes this system run smoothly and successfully lets neurites send information. 

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Cnidocytes

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Cnidocytes, 'stinging cells', are specialized cells that inject to capture prey or defend themselves from predators. These cells are special to cnidarians like jellyfish that are known for their stinging tentacles. In these cells are nematocytes that are the stinging organelles that are usually located at tentacles and also the mouth. Corals use this special feature in order to capture prey to feed on.