Phylum Nematoda Chapter 18 study guide Flashcards
Clade Ecdysozoa
synapomorphy?
Ecdysozoa synapomorphy: Ecdysis
(shed cuticle)
18.1 What is ecdysis?
Ecdysozoa synapomorphy: Ecdysis
(shed cuticle)
Phylum Nematoda
animal and synapomorphy
what clade are they in and synapomorphy of that clade?
“thread” (roundworms)
Synapomorphy:
Cuticle made of collagen
Clade Ecdysozoa synapomorphy Ecdysis
Phylum Nematoda features
- Marine, FW, terrestrial; Free living, parasitic; some beneficial
- Most are microscopic
- Eutely = set # cell divisions
In phylum Nematoda Pseudocoelom forms ________ _________
Hydrostatic skeleton
Form and function of Phylum Nematoda
Longitudinal muscle contraction only; whip-like motion
– muscle arms extend to nerves
-Complete gut
Names of parasitic Nematodes
Roundworms
Hookworms
Trichinella
Pinworm
Roundworms
how contracted
type of infection caused
how many are affected
Contract via soil
-Penetrate intestine, migrate to lungs,
enter pharynx, swallowed & live in
intestine
causes diarrhea and fever
~ 1 billion humans infected
Hookworms
how contracted
type of infection caused
how many are affected
Contract via soil;
- attach to the intestine, suck blood
causes intestinal disease
Trichinella
how contracted
type of infection caused
how many are affected
(causes trichinosis)
* Contract by eating raw or
undercooked meat
* Adults burrow through skin, live
in intestine & produce living
young
* Juveniles encyst in muscle
(intracellular parasite); muscle
becomes nurse cell
* Can contract from wild game
Pinworm
how contracted
type of infection caused
how many are affected
Most common nematode parasite
in US; 30% children, 16% adults
* Live in intestine, lay eggs in anus
What is the most common type of worm in the US?
Pinworm
18.5. Describe the life cycle of a filarial worm.
A. mosquito ingests microfilariae when biting human
B. Injested microfilariae passes through mosquito gut into hemocoel and eventually develop into infective juveniles
C. Infected mosquito transmits infective juveniles, which enter through wound puncture
D. Juveniles migrate via lymphatics to reagional lymph nodes
E. Adult worms develope to sexual maturity in afferent lymphatic vessels
F. Adult worms mate and female gives birth to microfilariae.
G. Microfilariae migrate to bloodstream
More simple life cycle of a filarial worm
-Requires insect vector
-Insect transmits juveniles to host
-Juveniles migrate into the lymphatic system
-Develop into adults in the lymphatic system( elephantiasis)
-Adults breed = give birth to microfilariae
-Microfilariae enter bloodstream of the host
18.6. What diseases are caused by filarial worms?
Heartworm
-Most common filarial worm in US
Onchocerciasis
- River blindness
-Transmitted by black flies
Elephantiasis
- legs look thick
