The Nematoda nervous system is made up of a nerve ring, which is made up of four ganglia, and nerve cords. The ganglia connect to four peripheral nerves which run the length of the body on the dorsal, ventral, and lateral surfaces. Longitudinal nerve trunks connect nerves in the esophageal region to nerves in the anus region. The nerves lie inside a cord of connective tissue, which lie beneath the cuticle and between muscle cells.
- The ventral is the largest ganglia and nerve trunk.
- This nerve has a double structure and runs toward the excretory pore.
- The dorsal nerve is responsible for motor control.
- The lateral nerves are for sensory.
- The ventral nerve also can combine both of these functions.
- Amphidial nerves from the front of an organism, branch from the circulatory ring surround by the pharynx toward the top of the body.
- Smaller nerves then run forward, to support the sensory organs of the head.
- Papillary nerves emerge from the nerve ring and innervate cephalic sensory papillae around the mouth.
- Amphids are a pair of complex sensory organs which open at the same level as the papillae. These are found in parasitic nematodes.
- Cervical papillae and derides are also found in parasitic nematodes around the nerve ring.
The last ganglion is the prenatal ganglion, which arises to two branches that pass downwards into the pseudocoel, which circles the rectum, forming the rectal commissure or posterior nerve ring. Peripheral nerves form a chain of fibers, which integrate with small commissures, providing nerves endings to sensory structures in the cuticle.
A nematodes body is covered with sensory bristles and papillae, which provide a sense of touch. Behind the sensory bristles on the head, are two small pit, aphids, which are covered with nerve cells, which could be classified as chemoreception organs.