Platyhelminths Flashcards
4 classes of platyhelminths
- turbellaria
- Cestoda
- monogenea
- Trematoda
What are platyhelminths referred to as
Flatworms
Characteristics of Platyhelminths
- symmetry
- lack
- bilaterally symmetrical
- lack coelom, circulatory system or specialized respiratory organs
Class Turbellaria characteristics
- lifestyle
- habitat
- size
- epidermis
- free living
- Maine, freshwater, moist terrestrial
- less than 1cm
- epidermis is ciliated and typically contains a large number of secretory cells
Dugesia sp.
- type
- known as
Turbellaria
Planarians
Dugesia sp.
- nervous system arrangement
- does it have an anus
Diffuse nerve net
No anus
Dugesia sp.
-movement
- moves like a fish
- move by muscular contraction waves along the ventral side (anterior to posterior). Possess circular muscles (forward) and longitudinal muscles (contract) and move in desired direction (looping)
Dugesia sp.
- advantages of thin body
- disadvantages of body shape
- why more advanced than Hydra
- gas exchange by diffusion
- no circulatory system or gut cavity so have to wait to expel food until feeding is done
- flatworms have tissues organized into organs and organ systems and bilaterally symmetrical and have brain and sense organs
Bdelloura sp.
- type
- habitat
- differences to Dugesia sp.
- Turbellaria
- Marine, commensal on book gills of horseshoe crab)
- shorter, wider, no auricle, pharynx in middle, nerve cords
Class cestoda
- known as
- type of parasite
Tapeworms
Endoparasites
Characteristics of Class Cestoda
- body divisions
- lack
- tapeworm body is divided into a scolex, a neck and a series of segments called proglottids
- outer body layer is nonciliated syncytium known as the tegument.
- as tapeworms do not have mouths or digestive systems, the tegument is highly specialized for nutrient uptake
Taenia solium (pork tapeworm)
- what’s on the scolex
- function of scolex
- what structures make up the major part of mature proglottid
- an anterior rounded side with suckers on lower edge and hooks at very top
- an anchoring organ that attaches to intestinal mucosa
- numerous testes and ovaries
Class monogenea characteristics
- type of parasite
- attachment organ
- tegument
- ectoparasite of the skin or gills of fish
- haptor (opisthaptor) on posterior
- tegument forms the outer body wall
Gyrodactylus sp.
- type
- habitat
- why so many hooks?
- monoangean
- freshwater on fish and frogs
- need to hold on to moving fish enough to parasitize
Class-Trematoda characteristics
- also known as
- suckers
- tegument
- flukes
- well developed suckers that are located in the region of the mouth and on the ventral body surface
- tegument is nonciliated and syncytial
Opisthorchis sinensis
- known as
- type
- function of oral sucker
- ventral sucker
- anus?
- Chinese liver fluke
- Trematoda
- getting nutrients from host
- contains ventral sucker
- no anus
Schistosoma mansoni sp.
- host
- causes
- type
Human blood vessels
Schistosomiasis
Trematoda
Schistosoma mansoni sp.
-compare male and female
- specific male and female types
- males are longer and have a ventral groove where females reside for maturation, mating and egg production
What is the functional attitude of the syncytial tegument found in the Trematoda, Cestodes and monogeneans
Protective barrier that guards the parasite against the hosts immune system
