Roundworms Flashcards

Questions and Answers

What phylum do roundworms belong to?

Nematoda

Explain what it means for roundworms to be pseudocoelomates.

Pseudocoelomate animals have a pseudocoelom, which is a fully functional body cavity partially lined by mesoderm.

Where are roundworms typically found?

In the human gut, soil, marine and freshwater habitats, and on land.

Describe some physical features of roundworms.

They range in size from microscopic to 3.3 feet, have a strong body covering, and some have bristles or a spear on their head. Signup and view all the answers

Roundworms are exclusively parasitic.

False Signup and view all the answers

What digestive feature did roundworms develop first?

Digestive tract Signup and view all the answers

How do most roundworms move nutrients and gases throughout their bodies?

They rely on diffusion since they have no circulatory or respiratory organs. Signup and view all the answers

Describe roundworm movement.

Roundworms move in a thrashing manner using body length muscles against a hydrostatic skeleton. Signup and view all the answers

What type of skeleton do roundworms have?

Hydrostatic skeleton Signup and view all the answers

Roundworms reproduce ________.

sexually Signup and view all the answers

List three factors attributing to human diseases related to parasitic roundworms.

Carelessness, lack of hygiene, poor sanitation Signup and view all the answers

How would you get hookworms?

By walking barefoot on contaminated soil. Signup and view all the answers

Describe the disease trichinosis.

It is caused by eating raw or undercooked pork infected with Trichinella spiralis larvae, leading to symptoms like abdominal discomfort and fever. Signup and view all the answers

Describe how hookworms would infect a human.

Infected feces release eggs onto soil, which hatch and release larvae that penetrate human skin. Signup and view all the answers

What is the most common roundworm that causes human infection?

Ascaris lumbricoides Signup and view all the answers

Study Notes

Roundworms Overview

Roundworms belong to the phylum Nematoda.
They can be found in diverse environments, including soil, marine, and freshwater habitats.

Body Structure and Features

Roundworms are pseudocoelomates with a "false cavity" partially lined with mesoderm-derived tissue.
They range in size from microscopic to about 3.3 feet (1 meter).
Their bodies have three tissue layers and a protective, flexible, grooved outer covering.

Lifestyle and Habitat

Approximately 60 types of roundworm inhabit humans, primarily in the gut, but some can migrate to other body parts.
Transmission to humans typically occurs through contaminated hands or skin contact with eggs or larvae in soil.

Movement and Nutrition

Roundworms lack circulatory and respiratory organs, relying on diffusion for gas exchange and nutrient movement.
They possess muscles along their length that enable thrashing movements, utilizing a hydrostatic skeleton formed by their pseudocoelom.

Reproduction

Roundworms have separate sexes and reproduce sexually; females produce eggs while smaller males produce sperm.
Fertilization occurs internally, with a complex lifecycle in parasitic species involving multiple hosts.

Diseases and Infection

Common diseases from parasitic roundworms are linked to lack of education, hygiene, and poor sanitation.
Key species causing human diseases include hookworms, pinworms, and Ascaris worms.
Hookworms infect humans primarily through skin penetration, often via the feet.

Specific Conditions

Trichinosis results from consuming raw or undercooked pork infected with the larvae of Trichinella spiralis, leading to symptoms like abdominal pain and fatigue.
Infection from hookworms involves larvae that mature in soil and penetrate human skin, with potential transmission through feces or contaminated areas.

Key Terms

Pseudocoelomate: An organism with a false body cavity partially lined by mesoderm.
Hydrostatic skeleton: A structure providing support through fluid pressure in a closed cavity.
Trichinosis: A disease caused by eating infected meat, leading to gastrointestinal and systemic symptoms.