Zoology Test 2b Flashcards
1
Q
How important are nonparasitic nematodes in world?
A
- extremely important as detritivores
- ubiquitous = everywhere
- pseudocoelomates (false body cavity (coelom))
2
Q
origin of pseudocoelom
A
- start with blastula with blastocoel in center
- blastopore starts to form
- blastocoel becomes pseudocoelom
- which creates the first complete digestive tract with mouth and anus
3
Q
characteristics of nematodes
A
- superficially simple
- little if any cephalization
- only longitude muscles are present
- no cilia, so no flame cells
- almost all dioecious
- no sexual reproduction just asexual
4
Q
cephalo
A
refers to head
5
Q
advantages of nematodes
A
- psuedocoelom gives them certain advantage over acoelomates
- have hydrostatic skeleton
- space for organs
- can circulate materials internally
- complete digestive system/tract
6
Q
excretion and osmoregulation in nematodes
A
- no flame cells
- excrete ammonia which diffuses across body wall
- osmoregulation is poorly understood
7
Q
circulation and respiration in nematodes
A
- no circulation or respiration systems
8
Q
parasitic nematodes
A
- easy to break the life cycle, very specific life cycle
- produce tremendous amount of eggs per adult
- just sexual reproduction
- hookworm, pinworm, whipworm
9
Q
life cycle of Ascaris
A
- medically important parasite
- lay 200,000 eggs per day
- juveniles develop inside shells and can remain viable on snail or plant for months or years in conditions are right
- eggs ingested with unwashed veggies or via unsanitary habits
- eggs hatch in digestive system, burrow through intestinal walls into veins and lymph vessels and finally carried to lungs
- larva enters lungs causing serious infection
- larvae eventually coughed up and swallowed then mature in intestines and feed
10
Q
symptoms of ascaris infection
A
- if infection heavy, abdominal symptoms, allergic reaction, wandering worms
- can have no symptoms
11
Q
Taxocara in animals
A
- commonly found in dogs and cats
- simple life cycle
- juveniles remain in state of arrested development unless female becomes pregnant, then infect embryos in uterus»puppies born with worms
12
Q
Taxocara in humans
A
cannot complete development in humans, but cause damage by wandering worms (visceral larva migrans)
13
Q
characterisitics of Necator americanus
A
- nematode parasite
- hookworm known as ‘American Killer’
- relatively light infection can cause mental retardation in children, retarded physical growth and loss of energy
- poor ppl mostly affected
- causes anemia» low oxygen, not enough RBC’s
14
Q
similarities of necator to ascaris and taxocara
A
- larvae passes from bloodstream to lungs and then to digestive system
- differs b/c eggs hatch in moist soil and juvenile worms penetrate vare feet
- life cycle broken by wearing shoes
15
Q
characteristics of trichinosis
A
- disease caused Trichinella spiralis
- is an intestinal parasite as adult
- differs b/c bloodstream carries larvae to muscle instead of gut
- encyst in muscle
- larvae causes painfully encysted muscles
- no cure exists
