MEDICAL BIOLOGY, HUMAN ANATOMY, PHYSIOLOGY AND PATHOLOGY - Ya.I. Fedoniuk 2010

BIOLOGY

SECTION 2. BIOCOENOTIC LEVEL OF LIFE ORGANIZATION AND HUMAN PLACE IN IT

2.4. MEDICAL HELMINTHOLOGY

Phylum Roundworms (Nemathelminthes)

Key CHARACTERISTICS OF THE phylum: 1) the body is unsegmented, cylindrical or spindle-shaped, and round in cross-section; 2) a primary body cavity is present inside the Skin-muscular sac; 3) unlike Flatworms, most Roundworms are dioecious; 4) circulatory and respiratory systems are absent; 5) the excretory system is either of the protonephridial type or represented by modified Skin glands; 6) unlike flatworms, the Digestive System features a third (posterior) section ending in an anus.

All roundworms that parasitize humans belong to the Class Nematoda (True Roundworms).



Last update: 08/08/2026

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