Platyhelminthes Flashcards
What does the life cycle of a cestode always involve?
Indirect and one or two intermediate hosts
What are examples of intermediate hosts?
Arthropods
Fish
Mammals
Can domestic animals be definitive hosts or intermediate hosts?
Can be both
Eucestoda subclass
True tapeworms
Cotyloda subclass
Pseudotapeworms
What do the bodies of tapeworms look like?
Long
Flat
Ribbonlike
Composed of segments
Do tapeworms have a body cavity?
No
Where are organs located in a tapeworms?
Loosely embedded in cellular tissue
How many regions does the tapeworm body consist of?
3 regions
Scolex
Neck
Body
Scolex
Head
Attachment organ with 2 to 4 muscular suckers
What are the muscular suckers called?
Acetabula
Tapeworms may have a snout that may have hooks. What is it called?
Armed vs Unarmed
Neck
Short
Undifferentiated tissue
What is another name for the body of the tapeworm?
Strobila
What is the body composed of?
Segments
What are the segments called?
Proglottids
What does each proglottid have?
Reproductive organs in three segments..
Immature
Mature
Gravid
What does gravid mean?
Pregnant
An owner does not bring in a fecal sample, just some proglottids. How do you determine what species it came from?
Break it open and examine it under the microscope
Why do we care what species the proglottid come from?
So we can determine the host.
Fleas
Is the pet hunting?
When a proglottid in the environment breaks open what does it release?
Thousands of hexacanth embryos
What must the egg be ingested by?
Intermediate host
What does the egg hatch into when it is inside the intermediate host?
Metacestode
What are the forms that metacestode can take?
Cystecercoid Cysticercus Coenurus Hydatid cyst Tetrathyridium
What does the form the metacestode takes depend on?
The type of tapeworm
What happens when the intermediate host is ingested?
The metacestode form attaches to the small intestine and matures into the adult
Cystecercoid
Arthropod intermediate host (flea)
Cysticercus
Mammalian intermediate host “bladder worm”
What metacestode form are both variation of bladder worms?
Coenurus
Hydatid cyst
Tetrathyridium
Solid body
Invaginated scolex
Capable of asexual reproduction
Multiply exponentially
