Cestodes Flashcards
Where is the life cycle of Pseudophyllidea?
Aquatic; 2 IH
Where is the life cycle of Cyclophyllidea?
Terrestrial; 1 IH
Where does the larval stage occur in IH?
In tissues
Where does the adult stage occur in DH?
Mostly SI
Adult tapeworm features
Features and function of scolex?
Attachment organ
- suckers, bothria or bothrida
What is the body of the worm called?
Strobila
Egg shedding in the Cyclophyllidea?
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
Egg shedding in Pseudophyllidea?
The uterus opens to the exterior by the genital pore and eggs are continuously shed into the faeces.
Osmoregulatory system?
Flame cells act as kidney to prevent swelling of the parasite
All Eggs contain an oncoshpere. What is that?
The larval worm
Features of Pseudophyllidea eggs?
- 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
Features of Cyclophyllidea eggs
- thick shelled
- hatch in the gut of the IH
Hexocanth Embryo
Cyclophyllidea:
Pseudophyllidea:
Cyclophyllidea: Oncopshere
Pseudophyllidea: Coracidium
What are the hexacanth hooks used for?
- 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
Types of metacestodes
Once ingested by the DH, what happens to the metacestode?
- Evagination - orientation of the holdfast organ
- Activation - initiation of muscular activity
