page_title: Earthworm
section_title: Nervous system
hierarchical_section_title: Earthworm / Anatomy / Nervous system
caption_attribution_description: English: Drawing of the anterior end of an earthworm, showing a side view of the animal (top) and a top-down view of the two nerve cords and brain (bottom).
context_page_description: An earthworm is a terrestrial invertebrate that belongs to the order Opisthopora. They exhibit a tube-within-a-tube body plan, are externally segmented with corresponding internal segmentation, and usually have setae on all segments. They occur worldwide where soil, water, and temperature allow. Earthworms are commonly found in soil, eating a wide variety of organic matter. This organic matter includes plant matter, living protozoa, rotifers, nematodes, bacteria, fungi, and other microorganisms. An earthworm's digestive system runs the length of its body. It respires through its skin. It has a double transport system made of coelomic fluid that moves within the fluid-filled coelom and a simple, closed circulatory system. It has a central and peripheral nervous system. Its central nervous system consists of two ganglia above the mouth, one on either side, connected to a nerve running along its length to motor neurons and sensory cells in each segment. Large numbers of chemoreceptors concentrate near its mouth. Circumferential and longitudinal muscles edging each segment let the worm move.
caption: Nervous system of the anterior end of an earthworm
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