Trematoda

Question 1

Which were the first real multicellular organisms

Answer 1

Phylum radiata

Question 2

Which are the most primitive members of the of the kingdom animalia

Answer 2

phylum porifera- sea sponges

Question 3

How does sea sponges catch food

Answer 3

by phagocytosis and then intracellular digestion

Question 4

What were the first organs to appear in animal evolution

Answer 4

reproductive organs

Question 5

What are some features of phylum radiata
(jellyfish)

Answer 5

Has radial symmetry- no left/right or dorsa/ventral
Diploblastic; 2 layers (endo& ecto)
No head=no brain
gastrovascular cavity: 1 opening
sexual and asexual repo
tentacles
PRIMITIVE nervous system

Question 6

Difference between organsisms with bilateral symmetry and organisms with radial symmetry?

Answer 6

bilateral symmetry has a head which moves forward first. Radial body reacts in same way in same direction
The head has sensory organs and brain in bilateral
more motile that radial organisms

Question 7

first organisms with bilateral symmetry

Answer 7

flatworms

Question 8

Life cycle of Obelia geniculata

Answer 8

*Immobile polyp colonies containing digestive hydranth+reproductive gonganium units

*gonganium reproduce asexually releasing medusa by budding

*Medusa/jellyfish swim freely and reproduce sexually releasing eggs+sperm into water

*Fertilised eggs develop into larvae that attatches to ocean floor as new polyps

Question 9

Features of Phylum Platyhelminthes (flatworms)

Answer 9

Bilateral symmetry
Tripoblastic (endo,ecto,meso)
Flat body no body cavity (acoelomate)
First organism where tissues organised in organs
No specialised exchange system
no/incomplete aoilmentary canal
mostly hermaphrodites

Question 10

Parasitic flatworms (platyhelminthes) belong to which classes?

Answer 10

Class trematoda (flukes)
Class cestoda (tapeworms)

Question 11

Features of class trematoda?

Answer 11

Oral sucker
ventral sucker- supports body to attach to other host
simple digestive system
hermaphrodites except shistomes
incomplete ailmentary canal (no anus)

Question 12

Name 3 trematoda parasites

Answer 12

Fasciola hepatica-big liver fluke

Dicrocoelium dentricum -liver fluke

Opisthorchis felineus - cat liver fluke

Question 13

Fasciola hepatica defintive host and intermediate host?

Answer 13

Def: cows and sheep

Int: freshwater snail

Question 14

Life cycle of Fasciola hepatica

Answer 14

*IMMATURE eggs released through bile ducts then faeces

• eggs release miracidia in water. These invade snail and multiply asexually

*eggs develop in cercariae in snail

*Snail releases cercairae. This excysts as
metacercariae on aquatic plants

*humans eat plants with cysts

*Goes to intestine and cysts release larave and eventually infects bile duct

*develops into adult flukes + produce eggs

Question 15

Dicrocoelium dentricum definitive and intermediate host

Answer 15

Def: Cows and sheep

Int: snail
int:ant

humans accidental host

Question 16

Life cycle of Dicrocoelium dentricum

Answer 16

• embryoned eggs with miracidia shed in faeces in def host

*snail eats faeces and miracidium hatches -becomes sporocysts in connective tissue. Then in digestive gland they form cercariae

*In their slime balls is cercariae. Ant second intermediate host. They injest the cercariae in slime

*metacariae develop in ant and ant gets eaten by cow

*Metacariae excysts in small intestine

*worms migrate to bile ducts and turns to adults

Question 17

Why cant humans get infected if we eat infected cow liver (dicrocoelium dentricum)

Answer 17

Because only METACARAIAE can infect us (mature )

Question 18

How does the cercariae affect ants

Answer 18

Cercariae goes to ganglia in brain and changes behaviour
Ant hangs on grass/leaves so easier to eat by cow and baso infect the cow

Question 19

Which area of the world does Opisthorcis felinbeus mainly infect

Answer 19

Asisa as raw fish in sushi eaten there

(fish int host)

Question 20

Genus opisthorchis definitive and intermediate host

Answer 20

def: human

Int: snail

second int host: fish

Question 21

Life cycle of Genus Opisthorchis

Answer 21

*Adult flukes deposit eggs thats passed through faeces

• injested by int host snail and eggs release miracidia

*cercariae reelased from snail and invade fish encysting as metacariae in muscles/scales

*Def hosts infected after eating undercooked fish with metacariae

Question 22

3 types of genus Schistosoma

Answer 22

S. hematobium
S. mansoni
S.Japonicum

Question 23

Genus Schistosoma (blood flukes) definitive and intermediate hosts

Answer 23

Def: human

Int: snail

Question 24

What is the differences between the sexes of schistosoma

Answer 24

male: body split, wide and short

female: thin, long and cylinderical (to lay eggs in small capillaries on surface of urinary bladder)

Question 25

Life cycle of Genus Schistosoma

CERCARIAE IS THE INFECTIVE STAGE!!!

Answer 25

*Miracidia hatch from eggs

*infect snails and multiply making cercariae

*cercariae released in water and DIRECTLY penetrates human skin

*they transform into larvae called Schistosomulae. They mature into worms in blood supply of liver, bladder, intestines

*worms lay many eggs and damage tissue. Eggs released into water through urine/faeces

Question 26

how to distinguish eggs of S.hematobium, mansoni and japonicum

Answer 26

mansoni: ova has lateral spine (from stool)

hematobium: ova has terminal spine (from urine)

japonicum: ova with lateral knob (from stool)

Question 27

what is the name of the land snail host in dicrocoelium dendriticum

Answer 27

Zebrina detrita