NEMATODES: ROUNDWORMS

What are Nematodes?

Roundworms Pseudocoelom Complete Digestive

Tract Cuticle 25,000 identified

but it is estimated that there are really close to 500,000 species

Some are parasitic

Inside a Nematode

Complete Digestive Tract

A continuous tube that goes from the mouth to the anus

Fluids absorbed from the digestive tract are spread through rest of body by pseudocoelom

The body cavity is in direct contact with the digestive tract

Hydroskeleton: soft bodied, fluid filled cavity

Contractions of longitudinal muscles allows for its muscle pattern

Digestive Tract Pseudocoelom

ANATOMY

Nematodes are often found in rotting living matter. Some are decomposers in soil and are found in the bottom of lakes and oceans. They may additionally be parasites that live in the tissue of plants and in the body tissue and fluid of animals.

Where are they found?

Carrot infested with the root knot nematode

Basics

Range from 1mm to 1m in size

Bilateral symmetry 3 tissue layer

construction of the body

Cuticle: tough nonliving material that prevents drying out of the body

Parasitism

Some nematodes are predators to eat other microscopic animals. They also invade many the tissue of some plants and animals. The cuticle protects the nematode against the host’s digestive system.

Dog heartworms are an example of a parasitic nematode.

Trichinella Spiralis

Humans can be a host

Enters the body through consumption of undercooked meat

The Cycle

Nematodes

Hookworms

Grab onto intestinal walls

Suck blood of host

Can cause anemia

Affects millions of people world wide as well as animals

Sources

http://www.ars-grin.gov/ars/SoAtlantic/fp/stpp/burelle/nematode.jpg

http://www.gettyimages.com/Search/Search.aspx?contractUrl=2&language=en-US&family=creative&p=nematodes&assetType=film&src=quick

http://edis.ifas.ufl.edu/LyraEDISServlet?command=getScreenImage&oid=13304504

http://www.apsnet.org/education/introplantpath/PathogenGroups/intronematodes/images/fig07.jpg

Sources (cont.)

http://www.phsource.us/images/Helminths/Trichinella_spiralis.jpg

http://www.greatlakesbcrescue.org/HealthNTraining/heartworms.JPG

http://pet-care-junction.com/blog/wp-content/uploads/2008/05/hookworms-in-pets.gif

Biology: Concepts and Connections (textbook)