Cestodes Flashcards
Cestodes are class of which phylum
Platyhelminthes
Common name od platyhelminthes
Flatworms
How does cestodes reproduce
Cestodes are hermaphrodite meaning that they have both male and female genital organs
Cestodes can be classified according to the presence of suckers to:
Cyclophyyllidea and Pseudophyllidea
Cyclophyllidea examples:
- Taenia saginata
- Taenia solim
- Hymenolepis nana
- Hymenolepid deminuta
- Echinococcus granulosus
- Multiceps multiceps
Pseudophyllidea examples:
Diphyllobothrium latum
Cestodes can be classified according to the site of the parasitic stage to:
Intestinal cestodes
Tissue cestodes
Intestinal cestodes examples:
- Taenia saginata
- Taenia solim
- Hymenolepis nana
- Hymenolepid deminuta
- Diphyllobothrium latum
Tissue cestodes examples:
- Cycticercus cellulosa
- Unilocular hydatid cyst
- Multilocular hydatid cyst
- Coenurus cerebralis
Why is extra-intestinal cestode infection more dangerous than intestinal infection?
- They affect internal organs including vital ones and may lead to fatal complications
- There is usually difficulty and delay of diagnosis
- Treatment is usually difficult as the drugs are less effective on the tissue stages and surgical removal is sometimes impossible
Cestodes body is ……
segmented
Cestodes body is divided to:
Head called Scolex Neck Immature segments Mature segments Gravid segments `
What does the scolex contain
Contains fixation organs –> 4 suckers
A typical scolex has a rostellum and hooks
What does the neck of the cestodes have
Contains stem cells to form the worm segments
Immature segments differentiation:
Undeveloped genitals
Mature segments differentiation:
Developed genitals
Gravid segments differentiation:
Ovary filled with eggs and atrophy of other organs
The segmets of the cestodes are called ….
Strobila
The body systems of the segmets include:
Muscular system
Nervous system
Excretory system
Reproductive systems
Muscular system function:
Consists of longitudinal, circular and radial bundles of muscle fibres, which help in the movement of the strobila as well as the scolex.
Nervous system function:
Nerve ganglia in the scolex. From which, anterior, posterior and lateral nerves arise to supply the scolex and strobila.
Excretory system functions
Flame cells embedded throughout the parenchyma, drain into two pairs of excretory canals.
Digestive tract in cestodes:
Is absent and the parasites absorb all substances through their external covering (the tegument).
Reproductive systems in cestodes:
Each mature segment has a complete set of male and female reproductive organs.
