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Flashcards in Flatworms Deck (62):
1

Two major evolutionary advances of flatworms

Cephalization
Primary bilateral symmetry

2

triploblastic and either acoelomate or pseudocoelomate

Flatworms

3

Which phylum:
Body flattened dorsoventrally
Triploblastic,
Acoelomate (atypical !)
Have a cellular ciliated epidermis

Phylum Acoelomorpha

4

Which systems do Phylum Acoelomorpha not have?

NO excretory or respiratory system. Lack protonephridia

-Monoecious

5

What does the digestive system of Phylum Acoelomorpha have

mouth → tube-like pharynx→sack-like gut (incomplete)
No anus

6

In many acoels what are absent and has no

the gut and pharynx are absent

7

What type of digestion does Acoelomorpha have

Intracellular digestion

8

Acoelomorphs lack a

true brain, Lack ganglion (mass of nerve cell bodies).

9

Diffuse system of anterior neurons connected to

radially arranged nerve cords,

10

What is :
crown of ciliated tentancles.
Efficient feeding device
Used for respiration

Lophophore

11

What does the Trochophore larva do?

free swimming, feeding, with ring of large cilated cells in front of mouth (prototroch).
Prototroch used in swimming and feeding.

12

In Lophotrochozoan Protostomes members (should) have in common either a

Lophophore or Trochophore larva.

13

Platyhelminthes lack a single unique character so they are NOT

monophyletic

14

Class Tubellaria are

polyphyletic.

15

In the Phylum Platyhelminthes which three classes are parasitic?

Trematoda, Monogenean and Cestoda

16

A. Ciliated ventral surface
B. Subtle muscular contraction
C. Dual-gland adhesive organs

Locomotion of Turbellaria

17

Locomotion of Turbellaria has what three parts?

1. Paired viscid cells (glands)
- produce adhesive secretions that
attach anchor cells to substratum

2. Anchor cells
- bear strain of attachment & allow
subtle muscular contractions to pull the animal forward
muscular contraction = pedal wave

3. Releasing cell (gland)
- secretes chemicals that release anchor cell attachment

18

what is a Protonephridium

an 'inverted' flagellated cell (flame cell) sitting in a 'mesh cup' (tubule end)

19

In osmoregulation the fluid is "ultra filtered" and modified and eliminated through what

nephridiopores
- Less important role as an excretory system (metabolic waste removal).

20

The nervous system has degrees of organization from a nerve plexus- how many nerve cords

nerve cords (1 – 3 pairs), with connecting nerves (ring commissures) forming a “ladder-type” pattern

21

What are the four parts of the nervous system?

Auricle, cerebral ganglion, nerve cord and ring commissures

22

Ocelli does what

light detection

23

Senses water flow

rheoreceptors

24

Statocyst are used for what

equilibrium

25

What are four characteristics of the class Turbellaria

Mostly free-living forms
Most are bottom dwellers in marine or freshwater
Freshwater planarians
Terrestrial flatworms limited to moist places

26

Carnivorous and detect food by

chemoreceptors

27

Planaria characteristics

-Food trapped in mucous secretions from glands and rhabdites
-Wrap themselves around prey
Extend the proboscis to suck up bits of food
Extracellular digestion completed by intracellular digestion.
Incomplete gut.

28

What are the three main classes of parasitic Platyhelminths.

Trematoda (Digenea)
Monogenea
Cestoidea

29

Most adults in Trematoda are

endoparasites of vertebrates

30

What are four adaptations for parasitism in Trematoda

-Penetration glands
-Glands to produce cyst material
-Hooks and suckers for adhesion
-Increased reproductive capacity

31

Which class has:
Most species dorsoventrally flattened
Usually leaf shaped
Covered by a syncytial tegument

Class Trematode Characteristics

32

Traditionally placed in the Class Trematoda but now forms its own class
Mainly ectoparasites
simple life cycle.
Single host

Monogenean (fish flukes)

33

What is also known as mammal flukes

Digenean Class

34

The digestive system in Digenean adults is

either absent or rudimentary

35

The excretory system in Digenea adults contains

ciliated cells (flame cells= protonephridia) extending into excretory tubules.

36

Most species are hermaphroditic for what

Digenea adults

37

How many stages are there in Digenean life cycle: Parasitic strategies

6

38

The Digenea Life cycle has ___ developmental stages

5

39

Digenea Life cycle has __ or more hosts. And which one is high and low

2. first one is high, the second is low

40

Digenea Life cycle: adulthood is reached only in

definitive* vertebrate host

definitive host is where sexual reproduction occurs

41

Digenea Location:
Adults-
Larvae-
parasitic forms-

Adults- usually parasites of vertebrate animals

Larvae-may be free-living or infect vertebrates or invertebrates.

parasitic forms- enter their hosts via the digestive system or by penetration of the skin.

42

Schistosome (blood flukes) are found in? and are agents of ____?

they have separate sexes

Found in veins, intestine and urinary bladder

Causative agents of schistosomiasis

43

What is the Infective stage called in schistosomiasis

cercariae (larvae)

44

What is swimmer’s itch?

Schistosome dermatitis -
when cercariae penetrate an unsuitable host (i.e. a human)

45

In Monogena most fish are

ectoparasites

46

some - found in urinary bladder, lower intestine of frogs and turtles.
in nature they cause little economic damage but can be very destructive in fish farming.

Monogena

47

Monogena life cycle goes through: Direct development.

“Monogenea” = 1 generation. 1 egg = 1 adult
No intermediate hosts → Autoinfection - possible for some species.

48

ciliated larvae, has eyespots, a rudimentary digestive system and an opisthaptor to attach to its new host.

Oncomiracidium

49

Why is the Opisthaptor important?

because they are typically ectoparasites and need to hang onto hosts.

50

What are the two hosts of Cestoda Tapeworms

definitive host - a vertebrate, (sexual reproduction)
intermediate hosts – either a vertebrate or an invertebrates.

51

What is the morphology of the Class Cestoda Tapeworms

quite different in appearance from the other members of the Platyhelminthes.

dorso-ventrally flattened, tape-like bodies.
Lack a head and gut.

52

What is is the general structure of an adult Class Cestoda Tapeworms

Segmented’ body
NB Not “true” segmentation

53

attachment to their host
contains suckers and hooks
Remnant of posterior part of body.

scolex

54

neck

zone of proliferation
- undifferentiated area behind the scolex

55

a chain of many reproductive units (proglottids )

strobila

56

immature proglottids - developing reproductive

mature proglottids: mature reproductive organs.
gravid proglottids: contain eggs in the uterus.

57

Tegument

-Cestodes, like trematodes and monogeneans, have no external motile cilia.

-entire surface of cestodes is covered with small projections called microtriches similar to microvilli seen in the vertebrate small intestine.

58

Larval Cestodes (Metacestodes) what is important to know

Most pathogenic stage
Result in economic loss

59

What is a causative agent of Taeniasis in dogs, cats and humans, and cysticercosis in the mammalian intermediate host (IH)

Taenia spp

60

What is the infective stage of the intestine of definitive host (DI) - adults

larvae (cysticercus/coenurus)

61

What is the infective stage of In various tissues of IH (usually forms cysts) -

egg with oncosphere

62

What can you get if you an ingest pork tapeworm

Cysticercosis
which commonly occurs in eyes or the brain blindness, serious neurological symptoms or death