Nematoda Flashcards
what is a large subphylum that is characterized by the presence of a cuticle?
ecdysozoa
what kind of coelom are nematodes?
Pseudocoelmate
What kind of coelom are arthropods?
coelomate
What ecdysozoa has these characteristics?
- free living or parasitic
- inhabit nearly every habitat
- pseudocoelmate
- circular cross-section
- tiny; less than 5cm long
- parasitic can reach more than 1m in length
Nematodes
In nematode anatomy, what is the cuticle made of that is secreted by the epidermis?
collagen
In nematode anatomy, what protects the worm from the external environment?
cuticle
In nematode anatomy, what does the fluid filled pseudocoel serve as?
hydrostatic skeleton
In nematode anatomy, what are the muscles layers made of?
Longitudinal muscles
What is the movement of nematodes like?
Whiplike
Are nematode digestive systems complete?
Yes
What do nematode digestive systems have?
mouth, pharynx, intestine, rectum, and anus (MoPIRA)
What do free-living nematodes feed on?
bacteria, yeasts, fungi, and algae (BYFA)
What kind of metabolism do adult parasitic nematodes have?
anaerobic metabolism
How many longitudinal nerve cords do most nematodes have?
4
what do the nerve cords form when they fuse at the anterior end around the pharynx?
Pharyngeal nerve ring
In nematode anatomy, what are complex chemosensory organs found near the head?
Amphids
In parasitic nematode anatomy, what do they have instead of amphids?
phasmids
What excretory structures do nematodes lack?
protonephridia
What do nematodes have as excretory systems instead?
gland cells, canal system, or both
Are nematodes dioecious or monoecious?
Most are dioecious
Which nematode sex is bigger?
Females
What kind of fertilization do nematodes have?
Internal
For parasitic nematodes what kind of juveniles do they have?
free-living juveniles
What is the most common nematode that is involved in human infections
- transmitted through contaminated soil
- larvae mature in lungs then move to throat to be swallowed
- 1-2 year life span
- feed on intestinal contents
Ascaris Lumbricoides
What nematodes have a hook like anterior end
- eggs passed through feces and juvenile feed on bacteria
- infective juveniles burrow into human skin then to intestine where they feed on blood
- cause anemia
- may stunt child growth
Hookworms
What nematode penetrate blood vessels
- juveniles reach skeletal muscle cells, and direct gene expression
- muscle cells become nurse cells
- gained from consumption of raw/poorly cooked meats
- infects many mammals
- can be fatal
Trichinella (causes trichinellosis)
What nematode cause relatively little disease
- most common parasite in the US
- adults live in large intestines
- eggs laid in anus
- itch can cross-contaminate bedclothes and hands
Pinworms (enterobius vermicularis)
What nematode causes elephantiasis that makes parts of the body swell?
Filarial worm; Wuchereria bancrofti
What nematode causes disease in dogs?
Filarial worms; heartworms
