ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Overview of Earthworm Anatomy

Updated on April 7, 2020

Earthworms are invertebrates meaning they do not have backbones such as reptiles, mammals, birds, fish, and amphibians. Examples of invertebrates insects, spiders, jellyfish, and millipedes.

Earthworms belong to a group of animals called Annelids. Annelids are segmented worms or worms with little rings around their bodies. The segments of the worms are well-defined - of similar size. They are separated from each other by septa (membranous partition). The exceptions are the head and tail regions which do not look alike.

An earthworm has about 100-150 segments each having muscles and bristles called setae. The setae help to control the movement of the worm through the soil. Furthermore, bristles hold firmly into the ground a section of the worm as the other part of the body protrudes forward.

The digestive system of earthworm consists of pharynx, the esophagus, the crop, the intestine, and the gizzard.

Earthworm | Source

When an earthworm eats food such as leaves through its mouth, it is grabbed by the pharynx. The pharynx pulls the food back into the mouth where it is mixed with saliva for easier swallowing. The food moves to the esophagus which contains calciferous glands. The glands release calcium carbonate whose task is to get rid of excess calcium in the earthworm's body.

The food then moves to the crop where it is stored. The crop acts as a storage compartment for food. From the crop, food moves into the gizzard.

In the gizzard, stones that had been swallowed are used by the strong muscles of the gizzard to grind the food. The food is moved into the intestine where it comes into contact with digestive juices that act as an aid in the digestion process by breaking the food into finer particles.

The wall of the intestine contains blood vessels. The digested food is absorbed in the blood and transported to the rest of the body.

Animal | Source

The circulatory system of an earthworm consists of three main blood vessels: the aortic arch, dorsal and ventral. The aortic arch acts like a human heart. The aortic arch pumps blood into the dorsal and ventral blood vessels. The dorsal blood vessels transport blood to the front of the earthworm's body while the ventral blood vessels transport blood to the back of the body.

Earthworms breathe through the skin since they don't have lungs. This is only possible through diffusion. For diffusion to occur, the earthworm's skin needs to be moist. This is the reason earthworms appear on the surface of the soil during the night when it cooler – there is low evaporation. Normally, the epidermis (skin) of earthworm releases mucous to keep the skin moist.

An earthworm does not have ears, nose, eyes or hands to help sense the environment around it. It uses its skin as a sensory receptor. Some species of earthworms use prostomium which is a tongue-like lobe found above the mouth of the earthworm. Prostomium acts the same function as the skin the earthworm - to sense the environment.

Earthworm Anatomy


This website uses cookies

As a user in the EEA, your approval is needed on a few things. To provide a better website experience, uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at:

Show Details
HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
LoginThis is necessary to sign in to the HubPages Service.
Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
AkismetThis is used to detect comment spam. (Privacy Policy)
HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the or domains, for performance and efficiency reasons. (Privacy Policy)
Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
MavenThis supports the Maven widget and search functionality. (Privacy Policy)
Google AdSenseThis is an ad network. (Privacy Policy)
Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
Index ExchangeThis is an ad network. (Privacy Policy)
SovrnThis is an ad network. (Privacy Policy)
Facebook AdsThis is an ad network. (Privacy Policy)
Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
AppNexusThis is an ad network. (Privacy Policy)
OpenxThis is an ad network. (Privacy Policy)
Rubicon ProjectThis is an ad network. (Privacy Policy)
TripleLiftThis is an ad network. (Privacy Policy)
Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)
ClickscoThis is a data management platform studying reader behavior (Privacy Policy)