Copyright

The Roundworm's Digestive System

Instructor: Danielle Haak

Danielle has a PhD in Natural Resource Sciences and a MSc in Biological Sciences

Roundworms are a type of nematode with a relatively simple digestive system. In this lesson, we will take a more detailed look at roundworm digestion and see how it contrasts to other groups of worms.

What is a Roundworm?

Roundworms are found within the phylum Nematoda. They are a group of worms more advanced than flatworms, but less advanced than earthworms (roundworms are not segmented like earthworms). A number of parasites, including hookworms, pinworms, and Trichinella are classified as different types of roundworms. In fact, more than 15,000 species of roundworms have been identified thus far.

Like other types of worms, roundworms live either in an aquatic environment or in the soil. It's necessary for them to stay wet or moist at all times. Non-parasitic roundworms will often live in the substrate of a body of water and they are free swimming, meaning they can venture about to find food. Parasitic roundworms get their nutrition from a host and can live either attached to the body, or even inside it. For example, parasitic species of roundworms like Ascaris live in the intestines of humans and can grow to a foot in length. Additionally, like other worms, they have an elongated, narrow cylindrical body that varies in size.

An adult parasitic roundworm
null

Roundworm Digestion

The roundworms represent a pretty magnificent leap in terms of how their digestive system is structured. Unlike their predecessors, roundworms have a tube digestive system, meaning food flows in one direction (in one end and out the other). This is in contrast to the digestive system of the flatworms: these organisms have a single opening. Food enters into a sac, digestion takes place, and waste is eliminated through the same opening. Once food enters a roundworm, it is pushed down the tube through a series of muscle contractions.

Let's take a closer look. A roundworm eats food that enters its mouth. The mouth signals the starting point of the digestive system. The food itself is consumed when the surrounding muscles (called pharyngeal muscles) contract, creating a vacuum-like suction. Some roundworms have a structure that they use to pierce food, either to suck out juices or to stab the item to ingest it. Once the food is in the mouth, it moves down to the pharynx (or throat). The pharynx is where food is crushed down before it continues into the long gut, or intestine.

To unlock this lesson you must be a Study.com Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use Study.com

Become a Study.com member and start learning now.
Become a Member  Back
What teachers are saying about Study.com
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account
Support