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The nervous system consists of two ventral nerve cords, which are usually fused into a single structure, and three or four pairs of smaller nerves per body segment. Only a few aquatic oligochaetes have eyes, and even then they are only simply ocelli. Nonetheless, their skin has several individual photoreceptors, allowing the worm to sense the ...
Bipalium species are predatory.Some species prey on earthworms, while others may also feed on mollusks. [10] [11] These flatworms can track their prey. [12]When captured, earthworms begin to react to the attack, but the flatworm uses the muscles in its body, as well as sticky secretions, to attach itself to the earthworm to prevent escape.
The sympathetic nervous system consists of nerve plexuses in the epidermis and alimentary canal. (A plexus is a web of connected nerve cells.) The nerves that run along the body wall pass between the outer circular and inner longitudinal muscle layers of the wall. They give off branches that form the intermuscular plexus and the subepidermal ...
A leech's nervous system is formed of a few large nerve cells. Their large size makes leeches convenient as model organisms for the study of invertebrate nervous systems. The main nerve centre consists of the cerebral ganglion above the gut and another ganglion beneath it, with connecting nerves forming a ring around the pharynx a little way ...
Like the vertebrate spinal cord, the function of the ventral nerve cord is to integrate and transmit nerve signals. It contains ascending and descending neurons that relay information to and from the brain, motor neurons that project into the body and synapse onto muscles, axons from sensory neurons that receive information from the body and environment, and interneurons that coordinate ...
Original – Diagram of the head of an earthworm including most of its major organs Reason Meets all of the FP criteria for SVG diagrams, including being freely licensed Articles in which this image appears Earthworm, Lumbricus terrestris FP category for this image Wikipedia:Featured pictures/Sciences/Biology Creator KDS4444
The nervous system is the only place in the body that contains cilia; these are all nonmotile and with a sensory function. [46] [47] The body is covered in numerous sensory bristles and papillae that together provide a sense of touch. Behind the sensory bristles on the head lie two small pits, or 'amphids'.
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