Phylum Nematoda Flashcards

Questions and Answers

What is a cuticle?

Non-cellular tough body covering

What are amphids?

Circular concentration sensory organs located at anterior of organism

What is ecdysis?

Shedding periodically 'Molting'

What are phasmids?

Circular concentration sensory organs located at posterior of organism Signup and view all the answers

What is the hypodermis?

Cellular layer lying beneath that secretes the cuticle Signup and view all the answers

What are copulatory spicules?

Needle-like mating structures found only in males Signup and view all the answers

What is hydrostatic pressure?

The pressure excreted by a fluid defined as force per unit area Signup and view all the answers

What is an alimentary canal?

Digestive tract consisting of mouth, pharynx, intestine, rectum, and terminal anus Signup and view all the answers

Describe Phylum Nematoda's classification as Eumetazoan, Triploblastic, etc.

Eumetazoan, Triploblastic, Bilaterally symmetric, Protostome, Ecdysoan, Pseudocoelomate, Schizocoelic Signup and view all the answers

List basic characteristics of Phylum Nematoda.

Pseudocoelom, Triploblastic, Extracellular digestion, Elongated circular bodies, Bilaterally symmetric, Protostomes, Aquatic, Terrestrial, No annuli, No segments, No septum Signup and view all the answers

What is the epidermis's role regarding the cuticle?

Produces the cuticle Signup and view all the answers

What hormone promotes ecdysis?

Ecdysome Signup and view all the answers

Nematodes have a hydrostatic skeleton.

True Signup and view all the answers

How do nematodes accomplish internal fertilization?

Male uses copulatory spicules to hold open female genital pore and muscular contraction shoots sperm into female's genital pore. Signup and view all the answers

Match the nematodes with their characteristics:

Ascaris lumbricoides = Intestinal roundworm Necator americanus = Hookworm Enterobius vermicularis = Pinworm Trichinella spiralis = Trichina worm Wuchereria bancrofti = Elephantiasis Signup and view all the answers

Are nematodes monoecious or dioecious?

Dioecious Signup and view all the answers

Nematodes are described as ______.

Dioecious Signup and view all the answers

What two ways can body-wall muscles in nematodes contract?

Longitudinal, cylindrical Signup and view all the answers

What is the structure of a nematode's digestive system?

Digestive tube with two openings (mouth and anus) Signup and view all the answers

Where is the fluid held in a nematode's hydrostatic skeleton?

Pseudocoelom filled with fluids Signup and view all the answers

Study Notes

Cuticle and Body Structure

Cuticle is a non-cellular, tough body covering, secreted by the epidermis.
Hypodermis is the cellular layer beneath the cuticle that produces it.
Nematodes have a pseudocoelom filled with fluid, acting as a hydrostatic skeleton, surrounded by muscles and bounded by the cuticle.

Sensory Organs

Amphids are circular, concentration sensory organs located at the anterior end, responsible for sensing the environment.
Phasmids, located at the posterior end, are similar sensory structures also involved in environmental sensing.

Ecdysis and Growth

Ecdysis refers to the periodic shedding or molting of the cuticle.
Ecdysome hormone promotes ecdysis, essential for growth and development in nematodes.

Muscular and Locomotion Features

Nematodes have longitudinal body-wall muscles that contract in a cylindrical shape, enabling a thrashing motion for movement.

Digestive System

Nematodes possess an alimentary canal consisting of an open digestive tract with two openings: mouth and anus.
The system includes structures such as the mouth, pharynx, intestine, rectum, and terminal anus.

Reproductive Characteristics

Nematodes are dioecious, having separate male and female individuals.
Fertilization is internal; males utilize copulatory spicules to hold the female's genital pore open and release sperm.

Taxonomy and Classification

Phylum Nematoda is eumetazoan, triploblastic, and bilaterally symmetric.
Classified into two main classes:
- Secernentea: Parasitic forms with three esophageal glands and ventral coiled amphids (includes intestinal worms, hookworms, filarial worms, pinworms).
- Adenophorea: Non-parasitic organisms with well-developed amphids and five esophageal glands (includes Trichinella, whipworm).

Characteristics of Nematodes

Basic characteristics include pseudocoelom, triploblastic organization, extracellular digestion, elongated and cylindrical bodies, and lack of annuli, segments, and septum.

Life Cycle and Effects on Humans

Ascaris lumbricoides: Found in intestines, feeds on intestinal fluids, causes weight loss, abdominal pain, and fatigue.
Necator americanus: Hookworm feeding on blood and mucus, produces fatigue and anemia.
Enterobius vermicularis: Pinworm residing in intestines causes itching and discomfort.
Trichinella spiralis: Trichina worm found in intestinal tissues, leads to symptoms of muscle pain.
Wuchereria bancrofti: Causes elephantiasis due to adult worms in lymphatics.

Key Terms Summary

Hydrostatic pressure: The force exerted by fluids, crucial for maintaining body shape in nematodes.
Copulatory spicules: Male nematode structures aiding in reproductive function.

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Description

Test your knowledge of Phylum Nematoda with these flashcards from Chapter 18. Each term, from amphids to cuticle, is defined to enhance your understanding of roundworms. Perfect for quick review and memorization.

Phylum Nematoda Flashcards - Chapter 18