cestodes

Question 1

Phylum:
Class:

• Intestinal Species
• Intestinal-Extraintestinal Species

Answer 1

Phylum: Platyhelminthes
Class: Cestoda

Intestinal Species:
* Taenia saginata
* Taenia solium
* Hymenolepis diminuta
* Hymenolepis nana
* Dipylidium caninum
* Diphyllobothrium latum

Intestinal-Extraintestinal Species:
* Echinococcus granulosus

Question 2

differences between two tapeworm orders: Pseudophyllidea and Cyclophyllidea,

Answer 2

notes

Question 3

general morphology

Answer 3

▪ Bilaterally Symmetrical
- when cut lengthwise, there will be two equal halves
- important for their streamline structure and movement within the host

▪ Adults are ribbon-like or tape-like in appearance, segment
- segmented into multiple units

▪ Hermaphroditic
- each segment or proglottid contains male and female reproductive organs
- allow cestodes to reproduce efficiently making them highly adaptable parasites

▪ Provided with a scolex which is an organ for attachment, a hold fast organ
- allows them to attach firmly to the host’s intestinal wall

▪ Body consists of three (3) regions:
Scolex
Neck
Strobila (Proglottids)

Question 4

briefly explain the 3 parts of adult tapeworms and its function (& location)

Answer 4

1. Head (Scolex) – Organ of Attachment
   - anchors the parasite to the intestinal wall of the definitive host
2. Neck – Region of Growth
   - site of proglottid formation (growth zone of strobila, where the new segments continuously develop and push the older ones down)
   - short but vital - for tapeworm’s elongation and reproductive capacity
   (@: behind the scolex)
3. Proglottids (Strobila) – Segmented Body
   - undergo maturation as they move posteriorly

Question 5

the chain of segments that make up the majority of the tapeworm body

Answer 5

Strobila
- composed of numerous proglottids that develop from the neck region
- has rudimentary secretory and nervous system

Question 6

why is the proglottids lacks in alimentary canal

Answer 6

as nutrients absorbed via cuticle (outer surface)

Question 7

it is a two shallow longitudinal grooves for attachment

Answer 7

bothria

Question 8

briefly explain the 3 types of proglottids

Answer 8

Immature:
no developed reproductive organs

Mature:
contains both male and female reproductive systems (hermaphroditic)

Gravid:
uterus packed with fertilized eggs ready to be released

Question 9

briefly explain the egg differences between orders
- embryo
- appearance
- defining features
- other features

Answer 9

transes

Question 10

it contain ciliated, free-swimming embryo

Answer 10

Order Pseudophyllidea

Question 11

contain Oncosphere (Hexacanth) –
equipped to actively penetrate
the intestinal wall of the intermediate host

Answer 11

Order Cyclophyllidea