Author:
victimsofadown
ID:
112154
Filename:
ZoologyTest3-Platyhelminthes
Updated:
2011-10-25 17:53:40
Tags:
ZoologyTest3 Platyhelminthes
Folders:

Description:
ZoologyTest3-Platyhelminthes
Show Answers:

  1. Acoelomate vs. pseudocoelomate vs. eucoelomate
    • Coelum: space between gut and epidermis completely surrounded by mesoderm
    • Acoelomate: “without coelum” – space between gut and epidermis is FILLED with mesoderm
    • Pseudocoelomate: “false coelum” – space between gut and epidermis has mesoderm only on outside (other side is endoderm).
    • Eucoelomate: “true coelum” – space between gut and epidermis is completely surrounded by mesoderm.
  2. Characteristics of acoelomate animals + phyla
    • Some cephalization (have head)
    • Bilateral symmetry
    • Have true organs
    • Protostome (“mouth first”)
    • Spiral cleavage
    • Simplest excretory and circulatory system
    • Triploblastic – Mesoderm in the form of parenchyma (muscle fiber and mesenchyme)
    • Three phyla – Platyhelminthes, Nemertea, Gnathostomulida
  3. Platyhelminthes – germ layers? Symmetry? Digestion? Symbiosis? Reproduction? Lifecycle? Special cells/structures? Other?
    • Triploblastic (Mesoderm in form of parenchyma layer)
    • Bilateral symmetry (Flat dorsoventrally)
    • Incomplete digestive system in some (mouth, no anus) – waste can exit through mouth OR diffuse through body walls OR flame cells -> excretory canal -> excretory duct (Protonephridia)
    • Free-living and parasitic
    • Most monogenea are ectoparasitic of fish (cause infestation)
    • All digenea and cestoda are endoparastic (cause infection)
    • Most are monecious (hermaphroditic) – not Schistosoma
    • Indirect (needs vector) and direct lifecycles
    • Definitive host is vertebrates in most cases (sexual reproduction occurs)
    • Some have eyespots (light intensity, not image-forming)
    • True muscles
    • Body fluid moves by muscular contraction (similar to skeletal-muscle pump for veins)
  4. What are the classes within phylum Platyhelminthes? List specific genera associated with each class
    • Turbellaria: Dugesia
    • Trematoda:
    • Subclass Digenea: Fasciola hepatica, Fasciolopsis buski, Clonorchis sinensis, Schistosoma mansoni, Shistosoma japanicum, Shistosoma haematobium, Paragonimus westermani
    • Subclass Monogenea: Gyrodactylus cylindriformis
    • Cestoda: Taenia saginata, Taenia solium, Diphyllobothrium latum, Echinococcus granulosus, Dipylidium caninum
  5. Class Turbellaria – Example? Symbiosis? Habitat? Cilia? Digestive system? Osmoregulation? Nervous system? Reproduction? Feeding style? Special cells/structures?
    • Planarians (eg. Dugesia)
    • Free-living
    • Mostly marine
    • Epidermis is ciliated on ventral side
    • Mouth on ventral side, no anus (incomplete digestive system)
    • Metabloic waste by diffusion through the body wall OR flame cells OR mouth
    • Osmoregulation required for Planaria because water is constantly entering (like Paramecium)
    • Flame cells (part of excretory system) remove water and waste (ammonia) for osmoregulation
    • Three types of neurons: sensory, motor, and association
    • Have neural ganglia, NOT brain
    • Asexual regeneration (cut in half = 2 organisms)
    • Monoecious, but practice cross fertilization to increase genetic variability
    • Fertilization is internal, and occurs in female oviduct
    • Simple life cycle
    • Carnivorous heterotrophs
    • Ocellia (light-sensitive eyespot)
    • Rhabdites cells (release mucus to ease locomotion)
    • Three types of muscle: longitudinal, circular, and radial
    • Gastrodermis has phagocytes to engulf food
    • Protonephredia = flame bulbs
    • Pharynx (in middle of animal) can extend and act as a vacuum for food.
  6. Class Trematoda – common name? Symbiosis? Cilia? Special cells/structures? Other?
    • Common name “flukes”
    • All parasitic
    • Tegument (“skin”) has no cilia and is syncytial (mutli-nucleated)
    • Have two suckers (oral and ventral)
    • Poorly developed sense organs
    • Subclasses Digenea and monogenea
  7. Subclass Digenea – Life Cycle? Species? General lifecycle? Why?
    • Require two hosts (intermediate host and definitive host)
    • Species include Fasciola hepatica, Fasciolopsis buski, Clonorchis sinensis, Schistosoma sp., Paragonimus westermani
    • General lifecycle: egg (contains miracidium) -> miracidium (ciliated larval stage that escapes egg, gets into water, and finds/penetrates snail) -> sporocyst (in snail, contains many rediae) -> rediae (in snail, contains many cercariae) -> cercariae (ciliated larva that gets out of snail) -> metacercaria encyst on vegetation or meat of fish -> adult in human
    • This type of lifecycle allows a single egg to rise to MANY progeny. Since odds of infection are not high, this increases odds of survival. Flukes are only animal where single egg can become multiple organisms.
    • Stopping the spread of flukes requires removing one of their intermediate hosts from the environment.
  8. Fasciola hepatica – Common name? Taxonomy? Host? Detection? Specific lifecycle?
    • Disease common name is “liver rot”
    • Phlylum Platyhelminthes, class Trematoda, subclass Digenea
    • Animals (sheep, cow, etc) Not typically found in human
    • Causes large white spots on liver of animal. Animal probably got infected by eating grass that had metacercaria.
    • Lifecycle: Cow poops egg -> egg in water -> miracidium escapes egg, find snail (Lymnea) -> penetrates snail -> becomes sporocyst within snail -> many rediae develop from single sporocyst -> inside rediae are many cercariae -> cercariae exits, finds vegation -> becomes metacercaria -> eaten by cow -> matures to adulthood in liver of cow -> cow poops egg…
  9. Fasciolopsis buski – Taxonomy? Host? Compare to Fasciola hepatica? Lifecycle?
    • Phlylum Platyhelminthes, class Trematoda, subclass Digenea
    • Found in human small intestine
    • Larger than Fasciola hepatica
    • Lifecycle: Human poops egg -> egg in water -> miracidium escapes egg, find snail -> penetrates snail -> becomes sporocyst within snail -> many rediae develop from single sporocyst -> inside rediae are many cercariae -> cercariae exits, finds vegation -> becomes metacercaria -> eaten by human -> matures to adulthood in small intestine -> human poops egg…
  10. Clonorchis sinensis – Common name? Taxonomy? Lifecycle? Symptoms? Location?
    • Common name “Human liver fluke”
    • Phlylum Platyhelminthes, class Trematoda, subclass Digenea
    • Lifecycle: human poops egg -> egg in water -> miracidium escapes egg, find snail -> penetrates snail -> becomes sporocyst within snail -> many rediae develop from single sporocyst -> inside rediae are many cercariae -> cercariae exits, finds fish -> penetrates fish, becomes metacercaria -> eaten by human -> matures to adulthood in bile duct of human -> human poops egg…
    • Note – Metacercaria found in meat of fish, not vegetation
    • Human can only become infected through ingestion of infected fish (Cooking will kill – pickling will not)
    • Doesn’t harm fish
    • Adult in bile duct, doesn’t cause an issue if only a few, but many will block the bile duct
    • Issue in rural areas of far eastern countries
  11. Give two reasons why tegument is beneficial to Platyhelminthes.
    • Constantly change surface protein molecules, making host antibodies useless
    • Can absorb food THROUGH tegument
  12. Schistosoma – taxonomy? Common name? Reproduction? Species/location/geo. Location? Symptoms? Life cycle?
    • Phlylum Platyhelminthes, class Trematoda, subclass Digenea (Old name Bilharzia)
    • Common name “blood flukes”
    • Dioecious w/ male bigger (wider) than female
    • Male has gynecophoric canal – females enter and reside during reproduction
    • S. mansoni: found in blood vessels of large intestine. Can kill humans. Causes bloody feces. [far eastern countries]
    • S. japanicum: in blood vessels of small intestine. Can kill humans. Causes bloody feces. Can cause dwarfing. [far eastern countries]
    • S. haematobium: in blood vessels of urinary bladder. Causes bloody urine (maturity in old Egypt). [Middle east/North African countries]
    • Cause ulceration in intestine, bladder
    • Schistosoma Dermatitis: (disease, not species) Schistosoma of a bird exits in feces, gets into water, cercaria enter human causing an itch, but die within 24 hours. [North America]
    • Do not have metacercaria and rediae stages
    • Lifecycle: human poops egg -> egg in water -> miracidium escapes egg, find snail -> penetrates snail -> becomes sporocyst within snail -> inside sporocyst are many cercariae -> cercariae exits, finds human -> matures to adulthood in human -> Schistosoma sexually reproduce -> human poops egg…
    • Cercaria have branched tails
    • Method of biological control would be crayfish, to remove the snails (intermediate hosts)
  13. What are the 6 major diseases according to WHO?
    • Schistosomiasis, malaria, filariasis, trypanosomiasis, leishmaniasis, and leprosy
    • 5 are parasites, only 1 (leprosy) is bacteria
  14. Paragonimus westermani – Taxonomy? Common name? Life cycle?
    • Phlylum Platyhelminthes, class Trematoda, subclass Digenea
    • Common name “lung flukes”
    • Adult fluke resides in lungs (human)
    • Crab/crayfish is intermediate host – metacercaria reside in meat. Human is definitive host (infection from eating crab or crayfish without cooking)
    • Metacercaria stage goes to human lung and matures into adults
    • Two methods of egg release…
    • 1. Escape through sputum (cough up/sneeze)
    • 2. Sputum is swallowed, egg goes to digestive system, excreted in feces.
    • Either way, egg gets into water and lifecycle is continued
  15. Subclass Monogenea - Species? Lifecycle?
    • Species include Gyrodactylus cylindriformis
    • All parasitic on gills or external surface of fish, suck blood of fish
    • Ectoparasitism and infestation (outside) NOT infection (inside)
    • Direct life cycle, single host (just fish)
    • Egg -> single larva (oncomiracidium) -> matures on gills of fish -> adult -> detaches and makes eggs
    • Opisthaptor: structure that attaches to fish gills and sucks blood
  16. Class Cestoda – Species? Common name? Gross anatomy? Reproduction? Lifecycle? Digestive system? Other?
    • Species include Taenia saginatus, Taenia solium, Diphyllobothrium latum, Echinoccous granulosus, Dipylidium caninum
    • Commonly named “tapeworms”
    • Three major parts: scolex (“head area” that has can have suckers and/or hooks for attachment), germinative zone (“neck area” where asexual reproduction occurs, lengthening tapeworm), strobila (“tail area” consisting of chains of proglottids)
    • Scolex may contain rostellum (elevation of scolex)
    • Immature proglottids -> mature proglottids (have testes, ovary, yolk gland, etc) -> gravid/ripe proglottids (uterus filled with eggs fills proglottid and all other structures disintegrate)
    • Gravid proglottids are ‘released’ by the cestode and exit in the feces, releasing eggs.
    • Nearly all are monoecious (hermaphroditic)
    • Cross fertilization is possible
    • Adults are found in vertebrates, intermediate hosts are invertebrates
    • Nearly all organisms can have a tapeworm (different species)
    • No digestive system, food absorbed through tegument
    • In general, do not harm host simply compete for food.
  17. Taenia saginata – Phylum? Class? Common name? Host(s)? Disease? Anatomy? Life cycle? Other info?
    • Phylum Platyhelminthes, class Cestoda
    • Common name “beef tapeworm”
    • Intermediate host – cattle, definitive host – human
    • Does not harm human
    • Scolex has 4 suckers, no hooks
    • Cysticercus (larval stage, infective for human) in beef
    • Excretory ducts have flame cells
    • Life cycle: egg -> bladder worm/cysticercus (in cattle) -> cysticerci becomes adult and sheds gravid proglottids (in human)
    • Human ingest cysticerci from uncooked infected beef, cattle ingest egg from human feces
  18. Taenia solium – Phylum? Class? Common name? Host(s)? Disease? Anatomy? Life cycle? Other info?
    • Phylum Platyhelminthes, class Cestoda
    • Common name “pork tape worm”
    • Intermediate host – pig OR human, definitive host – human
    • Cerebral cysticercosis: cysticercus in human can go to brain rather than other parts of the body causing devastating effects. Cannot be removed by surgery.
    • Scolex has rostellum, suckers, and hooks
    • Life cycle: egg -> oncospheres -> bladder worm or cysticercus (in pig) -> cysticerci becomes adult and sheds gravid proglottids (in human)
    • Note – cysticercus is also possible in human IF human ingests egg. (egg -> cysticercus)
  19. Diphyllobothrium latum – Taxonomy? Host(s)? Symptoms? Anatomy? Life cycle?
    • Phylum Platyhelminthes, class Cestoda
    • Intermediate host – fish, definitive host – human
    • Competes with vitamin B12, which is needed for proper RBC production.
    • Causes megaloblastic/pernicious anemia (RBCs become huge, unable to fit into capillaries)
    • Lack of gas exchange results in lethargy, tiredness, etc but not death.
    • Scolex has longitudinal grooves (no suckers/hooks)
    • Cysticercus in fish
    • Infection by eating infected raw fish (especially in the Great Lakes area)
  20. Echinococcus granulosus – Taxonomy? Host(s)? Symptoms? Anatomy? Other?
    • Phylum Platyhelminthes, class Cestoda
    • Definitive host – dogs and other canine, intermediate host – human
    • Hydatid cyst: cysticercus in human becomes HUGE. Can only be removed by surgery (no medication). If hydatid cyst ruptures during surgery, patient will die instantly from anaphylactic shock.
    • Smallest tapeworm in class, only 3 segments. Entire animal less than 1 cm.
    • Possible infection by petting dog who has rolled in its infected feces -> eggs on hand -> hand in mouth
    • Hydatid cyst can be formed in stomach, brain, arms, etc. Doesn’t HAVE to be one area.
  21. Dipylidium caninum – Taxonomy? Common name? Symptoms? Host(s)? Anatomy? Prevention?
    • Phylum Platyhelminthes, class Cestoda
    • Common name “dog tapeworm”
    • Children can contract, but adult immune system will easily destroy. Would contract by eating infective flea.
    • Intermediate host – flea, definitive host – dogs (mostly), some cats
    • Gravid proglottids look like rice granules
    • Good method of prevention is to place mothballs into a vacuum bag when vacuuming. This will kill the fleas, and end the cycle.
  22. Describe the adaptations cestodes have developed to be successful
    • Do not harm hosts (in general)
    • No GI tract, absorb nutrients through tegument
    • Have cuticle to prevent digestion
    • Have hooks/suckers for attachment to host
    • Asexual reproduction results in thousands of eggs released in an “assembly line” type fashion via proglottids
  23. Compare/contrast Taenia solium and Taenia saginata
    • T. solium: Intermediate host pig/human, definitive host human, cerebral cysticercosis, uterus branches less than seven times, scolex has 4 suckers/hooks/rostellum
    • T. saginata: Intermediate host cow, definitive host human, does not harm human, uterus branches more than seven times, scolex has 4 suckers/no hooks