Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PARA424 > lecture 6 > Flashcards

lecture 6 Flashcards

1
Q

what group of organisms is the class trematoda?

A

digenetic flukes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

trematodes are commonly referred to as ____

A

flukes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

why are digenetic flukes, digenetic?

A

their life cycle involves two hosts, meaning their are two beginnings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the first intermediate host of digenetic trematodes?

A

almost always a mollusk (usually a snail)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the definitive host of a digenetic trematode?

A

a vertebrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

many ____ stages occur in the intermediate host

A

larval

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

___ trematodes are found in the definitive host

A

adult

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

all trematodes are obligate ___ parasites in all classes of vertebrates

A

endo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what parts of the host do digenetic trematodes infect?

A

the blood vessels, GI tract, lungs, or liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are the larval stages of the digenetic trematode?

A
  1. egg
  2. miracidium
  3. sporocyst
  4. redia
  5. cercaria
  6. metacercaria
  7. adult flukes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are the characteristics of the adult digenetic trematode?

A

the 2 suckers:

  1. oral sucker - at anterior end surrounding mouth - for attachment and feeding
  2. acetabulum - a.k.a the ventral sucker - located mid-ventrally to oral sucker; no internal opening; for attachment to host
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

suckers are strongly muscularized consisting of bands of ___ ___

A

smooth muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

asexual reproduction/larval stages occur in the ___ host

A

first intermediate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

the adult digenetic trematode’s body wall is a ____

A

tegument

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the two layers of the digenetic trematode’s tegument?

A
  1. syntegument

2. cytotegument

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is the syntegument?

A
  • it is the outer layer, contains mitochondria, secretory bodies, and occasional spines
  • it is a chemical layer that lies on top of the outer cell membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is the cytotegument?

A
  • cell bodies beneath the syntegument
  • each cell contains a nucleus and organelles
  • involved in production of mucus
  • separated from syntegument by layers of tegumental muscle
  • connected to syntegument by cytoplasmic bridges
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are the functions of the tegument?

A
  1. osmoregulation
  2. synthesis and secretion of mucus (to protect against host enzymes)
  3. absorption of nutrients for trematode nutrition
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are the characteristics of the trematode digestive tract?

A
  • muscular mouth creates sucking action
  • short esophagus leads into 2 long blind-ending cecum (=intestinal ceca)
  • no anus
  • proteins are digested in the lumen of the intestine and are absorbed through the intestinal epithelium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is the parenchyma?

A

loosely arranged cells filling space between internal organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what does the excretory system do?

A

removes excess water that has diffused into the worm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are flame cells?

A

cells that contain beating flagella that create a hydrostatic pressure which draws water from the parenchyma into the collecting duct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

where are the flame cells located in the adult digenetic trematode?

A

at the posterior end of the worm is an excretory bladder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what does the digenetic trematode’s nervous system consist of?

A

the ladder type-system and sense organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what does the ladder-type system consist of?

A

anterior ganglionic mass, lateral nerve trunks, and connecting commissures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

where are the sense organs located in adult digenetic trematodes?

A

at the cellular level within the tegument

27
Q

sense organs of ______ stages are well developed

A

free-swimming larval

28
Q

reproductive systems are extremely ___ and ____

A

elaborate

specialized

29
Q

almost all digenetic trematodes are ______ with one exception: ____

A

hermaphroditic

schistosoma spp

30
Q

trematodes ____ in three possible ways

A

reproduce

31
Q

what are the three possible ways of reproduction in trematodes?

A
  1. auto-fertilization
  2. cross-fertilization
  3. living together as a long-term unit, with the larger male surrounding the smaller, thinner female worm
32
Q

what does the male reproductive system consist of in the adult digenetic trematode?

A
  1. two testes
  2. sperm ducts - consist of 2 vas efferentia which join to form a single vas deferens
  3. vas deferens - leads into the cirrus sac
33
Q

____ and ___ of the 2 testes are important taxonomic characters

A

shape

position

34
Q

what does the female reproductive system consist of in the digenetic trematode?

A

a single ovary that produces eggs which pass along the oviduct to the ootype

35
Q

shape and position of the ovary in relation to the testes is important in ____

A

identification

36
Q

what is the morphology of the digenetic trematode egg?

A

well developed eggshells enclosing the ovum, one or more sperm cells, and a number of vitelline cells

37
Q

the digenetic trematode egg is usually ____

A

operculate

38
Q

what is the difference in egg morphology between trematodes and schistosomes?

A

schistosome eggs are non-operculate and are ornamented with spines

39
Q

following fertilization, an embryo or _____ develops

A

miracidium

40
Q

the hatching eggs involves the release of the _____

A

opercular cap (if present)

41
Q

what are the important factors involved in the eggs hatching in the external environment?

A

light, temperature and changes in the osmotic pressure

42
Q

in all cases the egg hatches to release the ____

A

miracidium (usually the free-swimming form)

43
Q

what is the miracidium?

A
  • the ciliated (in most but not all cases) larval stage that is hatched from the egg
44
Q

in most cases the miracidium is usually a free-swimming stage that seeks out the primary, and in some cases, _____ host of these parasites

A

intermediate

45
Q

what happens in the case where the miracidium is not a free swimming stage?

A

the eggs are ingested, and hatch in the intestine of the mollusk liberating the miracidium, from where it immediately penetrates the intestinal wall to invade the molluskan tissues

46
Q

different species of trematode will undergo different patterns of larval development, although the ____ will ____ develop into a sporocyst to start with

A

miracidum

always

47
Q

the miracidium metapmorphoses to the ___ ___ stage through the loss of ciliated cells, the penetration glands, and the apical gland

A

early sporocyst

48
Q

in some cases, the sporocyst develops within the ____ host as a hollow fluid filled germinal sac containing germ cells into ___ ____

A

molluskan

mother sporocysts

49
Q

germ cells multiply and develop internally into ___ ____, which are essentially the same as their parent sporocysts

A

daughter sporocysts

50
Q

if daughter sporocysts are formed, the second larval stage, the ___, do not develop

A

redia

51
Q

the redia stage is ___ in the schistosomes

A

absent

52
Q

the cycles of ___ ___ within the mollusc result in an enormous increase in the reproductive potential of these organisms, where a single ____ can give rise to many _______ of cercariae

A

asexual division
miracidium
hundreds of thousands

53
Q

what larval stage are the redia considered?

A

the 2nd stage

54
Q

what host do the redia develop in?

A

the molluscan host (but absent in some groups, such as schistosomes)

55
Q

redia differ from the sporocyst in that they are much more ___ and possess a ____ gut

A

active

simple

56
Q

the gut consists of a mouth that opens into a large muscular ____, which in turn opens into a ___ ___

A

pharynx

simple intestine

57
Q

externally, behind the mouth, many redia have a ___ -___ ___, below which the birth canal opens and from which either ____ or ____ ____ emerge

A

ridge like collar
cercariae
daughter redia

58
Q

what life stage of the trematode is the infective for the vertebrate host or plant?

A

the cercarial stage

59
Q

what is unique about the trematode cercaria?

A

exhibit considerable variations in structure, which is very important taxonomically

60
Q

the cercariae lead a brief free-living existence until a suitable _____ or place of encystment can be found

A

second intermediate host

61
Q

some cercariae _____ the definitive host directly or the cercariae might be ____ by the definitive host

A

penetrate

eaten

62
Q

what occurs in the case that the parasite employs three intermediate hosts?

A

the cercariae penetrate the second intermediate host to form a resting stage, the mesocercaria

63
Q

what are the possible final intermediate hosts?

A
  1. a fish
  2. an arthropod, or
  3. another mollusk

PARA424 (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions