Exam 3 Flashcards
Structure
Strobila
-Made up of many individual proglottids (segments)
-Older proglottids at the posterior end of the worm
Stabilization–takes place at the anterior end of the worm
Structure pt.2
The tegument and muscle fibers of the tapeworm are continuous there for cestodes are not segmented like annelids or arthropods
End of the tapeworm
-Detach
Dissintegrate–apolysis
Be released via pores
The head is a scolex which has holdfast organs that allows the worm to attach to the GI tract
-suckers
-grooves
-hooks
-spines
-glands
-tentacles
Anterior forms of attachment
suckers/acetabula
-usually 4 or present
Example
-taenia
–in acetabular worms
bothria
-shallow pits or long grooves
-muscular
usually 4
project from scolex
leaf-like margins
Diphyllobothrium spp.
marine mammals–sea lion
Tegument
Important in its absorptice capacity
Remember, tapeworkms have no digestive tract
Structure and function of body covering has long been of great interest
-Living tissue with high metabolic activity
Tegument pt.2
Tapeworms possess a basic tegument like the trematodes
Outer membrane projects numerous fingerlike projections called microtiches
In the groups–tetraphullideans and trypanorhynchs ‘-highly ornate
have 4 kinds of microtriches existing on the scolex
Reproduction
Monecious
usually each segment has a complete set of male and female reproductive structures
Segments mature as they move down posteriorly
Cestodes
All tapeworms of humans belong to the groups cyclophyllidea also formerly known as pesudophyllidea
Usually no medical or economical impact
Morphological diversity is astonishing
Diphyllobothriidea
Genital pores may be lateral
Life cycle includes crustacean 1st IH and fish 2nd IH
Hexagonoporus physeteris
Species in sperm whales
30 meters long
4-14 sets of genetalia
has 45,000 segments (stobula)
Caryophyllidea
Most are intestinal parasites of freshwater fishes
Monozoic
-Very simple–scolex has depressions called loculi
- lack a scolex in some species
Anterior end is very motile
Earthworm has intermediate host
Spathebothriidea
Parasites of marine and freshwater fish
Complete absence of segmentation
possess a linear series of internal proglottids
Scolex unarmed
No life cycle known
Tetraphyllidea
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Order cyclophyllidea
Generally tapeworms of birds and mammals
Possess four symmetrically arranged cup suckers or acetabular
Rosrellum may or may not possess hooks
Most species small
Genital pores usually lateral
Non ciliated embryo
Non-operculate shell
Taenidae
larval stages are called metacestodes
mammals serve as intermediate hosts
Taenia solium
Humans can be the DH or IH host
metacestode(larval) form: cysticercus
If DH will have long worms in the GI tract