Biology Chapter 11: Phylum Nematoda

What is the characteristic of the excretory system in class Aphasmida?

What is the function of stichocytes in Trichinella spiralis?

Where do the adult stages of Trichinella spiralis live?

What is the result of infection by Trichinella spiralis in humans?

What is the characteristic of the esophagus in order Trichurida?

How does the human get infected with Trichinella spiralis?

What is the feature of the male Trichinella spiralis?

What is the characteristic of class Phasmida?

What is the characteristic of the posterior body region in order Oxyurida?

What is the ploidy of the male and female in order Oxyurida?

Phylum Nematoda: Class Aphasmida

Lacking phasmids (caudal sensory organs) and excretory system is absent or reduced
Males have one spicule or no spicule at all

Order Trichurida

Anterior end of the worm is more slender than the posterior end
Esophagus has one or two rows of gland cells called stichocytes along its posterior portion
Excretory system is absent
Bacillary bands are present, consisting of glandular and non-glandular cells
Glandular cells may be involved in ion and osmotic regulation
Non-glandular cells may be involved in cuticle formation and food storage

Trichinella spiralis

A parasite of mammals, including humans
Immature and adult stages can be found in the same host
Body length is 2-4mm
Esophagus occupies ⅓ - ⅟2 of body length
Male lacks spicule, but has a copulatory pseudobursa
Life cycle involves ovoviviparity, with juveniles moving through blood circulation and encysting in skeletal muscles
Humans are infected by consuming pork flesh infested with cysts
Infection causes fever, diarrhea, and damage to blood vessels and infected organs
Stichocytes secretion alters muscle nurse cell function, leading to nuclei hypertrophy and myofibril loss

This quiz covers the basics of Phylum Nematoda, including characteristics of Class Aphasmida and Order Trichurida, their physical features, and unique biological systems.