Cestodes

Question 1

Where is the life cycle of Pseudophyllidea?

Answer 1

Aquatic; 2 IH

Question 2

Where is the life cycle of Cyclophyllidea?

Answer 2

Terrestrial; 1 IH

Question 3

Where does the larval stage occur in IH?

Answer 3

In tissues

Question 4

Where does the adult stage occur in DH?

Answer 4

Mostly SI

Question 5

Adult tapeworm features

Answer 5

Question 6

Features and function of scolex?

Answer 6

Attachment organ

• suckers, bothria or bothrida

Question 7

What is the body of the worm called?

Answer 7

Strobila

Question 8

Egg shedding in the Cyclophyllidea?

Answer 8

Gravid segments are shed into the faeces -> eggs are released when the segment ruptures or eggs are pushed out of the genital pore by muscular contractions

Question 9

Egg shedding in Pseudophyllidea?

Answer 9

The uterus opens to the exterior by the genital pore and eggs are continuously shed into the faeces.

Question 10

Osmoregulatory system?

Answer 10

Flame cells act as kidney to prevent swelling of the parasite

Question 11

All Eggs contain an oncoshpere. What is that?

Answer 11

The larval worm

Question 12

Features of Pseudophyllidea eggs?

Answer 12

• oncosphere is surrounded by a ciliated embryophore which is surrounded by a thin operculated shell.
• the larva uses the ciliated embryophore to swim around
• the embryophore is lost when the coracidium enters the host

Question 13

Features of Cyclophyllidea eggs

Answer 13

• thick shelled
• hatch in the gut of the IH

Question 14

Hexocanth Embryo

Cyclophyllidea:

Pseudophyllidea:

Answer 14

Cyclophyllidea: Oncopshere

Pseudophyllidea: Coracidium

Question 15

What are the hexacanth hooks used for?

Answer 15

• for the oncosphere to tear its way out of its membrane
• potentially aids in burrowing through the gut wall to reach its site to develop into a metacestode

Question 16

Types of metacestodes

Answer 16

Question 17

Once ingested by the DH, what happens to the metacestode?

Answer 17

1. Evagination - orientation of the holdfast organ
2. Activation - initiation of muscular activity