Module 4 Flashcards
● Cylindrical in shape Has a complete alimentary canal
NEMATODA
Roundworms
● sexes are separate Either free-living or parasitic
NEMATODA
Diecious
● they possess a false coelom
NEMATODA
Pseudocoelomates
● Flattened dorsoventrally in shape
PLATYHELMINTHES
Flatworms
Absent digestive system
PLATYHELMINTHES
Monoecious (Cestodes, Monoecious flukes)
Diecious (Blood flukes - [?] spp)
PLATYHELMINTHES
Schistosoma
Strictly parasitic
PLATYHELMINTHES
● Coelom (body cavity) is absent.
PLATYHELMINTHES
Acoelomates
requiring more than 1 host in their life cycle, except Hymenolepis nana which may complete its lifecycle in 1 host.
heteroxeneous
require 3 hosts (a definite host and 2 intermediate hosts — first intermediate host, and second intermediate host) to complete their lifecycle. And consist of 3 larval stages
pseudophyllids
require 2 hosts (a definite host and an intermediate host), and consist of 2 larval stages
cyclophyllids
The life cycle of cestodes consists of four developmental stages:
○Egg
○Oncosphere
○Metacestode
●The ciliated oncosphore of pseudophyllids is termed
Coracidium
do not possess cilia
oncosphere
The hexacanth embryo develops into a [?] that becomes encysted in extra intestinal sites of the intermediate host.
metacestode larva
It already contains scolex.
metacestode larva
■Depending on the species, larval stages of cestodes may be described as either
solid or bladder-type
1.Pseudophyllidean pattern
a.Solid larva
b.Procercoid
c.Plerocercoid or Sparganum
2.Cyclophyllidean pattern
a.Cystic/Bladder larva/worm
b.Cysticercoid
Metacestodes
1.Pseudophyllidean pattern
2.Cyclophyllidean pattern
3.Cysticercus
4.Coenurus
5.Yep
has a fully developed cyst wall containinga single invaginated scolex. The hollow cavity is filled with f luid thus, it is called a true “bladder worm”; seen among Taenia species
3.Cysticercus
multiple scolices developed from the innergerminal wall; seen in Multiceps multiceps.
4.Coenurus
germinal layer may produce many scolices anddevelop many daughter bladders (or brood capsules), each of which, in turn, produces many protoscolices internally; seen in Echinococcus species.
5.Yep
characterized by absence of body cavity
a.Solid larva
solid, relatively globular, with the scolex invaginated into the body of the larva
b.Procercoid
solid, elongated, with the head free or invaginated only into the neck
c.Plerocercoid or Sparganum
- characterized by a body cavity that may or may not be well-developed and containing fluid
a.Cystic/Bladder larva/worm
a.Cystic/Bladder larva/worm - characterized by a body cavity that may or may not be well-developed and containing fluid b.Cysticercoid- not well-developed, with a rather small body anteriorly, into which the scolex is invaginated, and frequently with solid, elongated caudal portion; seen among Hymenolepis species and Dypilidium caninum
- not well-developed, with a rather small body anteriorly, into which the scolex is invaginated, and frequently with solid, elongated caudal portion; seen among Hymenolepis species and Dypilidium caninum
b.Cysticercoid
○Among the pseudophyllids, the immature eggs embryonate and release the [?] in water which are ingested by its first intermediate host.
oncospheres (coracidia)
○Within the first intermediate host the coracidium develops into a .
procercoid
○The first intermediate host is ingested by the second intermediate host where the procercoid develops into a
plerocercoid larva
■The definitive host becomes infected by ingestion of the intermediate host’s flesh containing the [?]. The [?] attaches into the intestinal mucosa, strobilates and develops into the adult worm. Eggs from the [?] are then passed in feces.
metacestode larva
metacestode scolex
gravid proglottids
■The [?] are mature, thus are readily infective but hatch only after ingestion by intermediate host. Hatching of the eggs will release the [?] which migrate to extra intestinal sites and become a [?], which may be [?], depending on the species.
cyclophyllidean eggs
oncospheres
metacestode larva
cysticercus, cysticercoid, coenurus, hydatid
