EVERYDAY SCIENCE

Detailed explanation-1: -The nerve net is the simplest form of a nervous system found in multicellular organisms. Unlike central nervous systems, where neurons are typically grouped together, neurons found in nerve nets are spread apart. This nervous system allows cnidarians to respond to physical contact.

Detailed explanation-2: -In the cnidarian body, the nerve net serves as a sensory locator; neuron cells stretch all around the animal’s body and allow the cnidarian to detect chemical changes, to capture prey, and to move in response to a stimulus. This kind of expansive nerve net is also known as a diffuse nerve net.

Detailed explanation-3: -In addition, many other cnidarians are mostly sessile (e.g., corals, anemones). In cnidarians a net of neurons lies between the inner and outer body walls. Unlike nerves in most other animals, these nerves can transmit impulses in any direction.

Detailed explanation-4: -While the subumbrellar muscle sheets of some hydromedusae are aneural, others use both electrical conduction and neuronal input from nerve nets ( Spencer 1978; Spencer and Satterlie 1981; Satterlie and Spencer 1983; Satterlie 1985, 2008 ).