Chapter 14 Study Questions - Flatworms Flashcards
Learn Chapter 14 for Exam 2 on March 28th
- List and/or describe 8 characteristics of the phylum platyhelminthes.
- Bilaterally symmetrical
- Triploblastic - Three germ layers
- Cephalization - Development of head
- Body flattened dorsoventrally
- Tissues, Organs, Systems - level of development.
- Ladder Type nervous system - Anterior Ganglea
- Tegument - Exterior body covering
- Excretory System - Flame cells, Protonephridia- early model for kidney
- Circulatory system and one way alimentary canal
- Musculatory system
- Identify or describe triploblastic, cephalization, and bilateral symmetry.
- Triploblastic - Body that contains a middle germ layer, mesoderm, derived from the endoderm. Three germ layers - ectoderm,endoderm, and mesoderm - produce all adult body structures.
- Cephalization - differentiation or develepment of a head or development toward head
- Bilateral Symmetry - applies to animals that can be divided along a sagital plane into two mirrored portions - right and left havles.
- Name the 4 classes of platyhelminthes and give examples of each.
- Turbellaria - Dugesia, Euplanaria
- Trematoda - Clonorchis sinensis aka: chinese liver fluke or human liver fluke
- Monogenea - Dactylogyrus, Gyrodactylus
- Cestoda - Tapeworms… Beef Tape worm= Taenia saginata, Prk Tape Worm= Taenia solium, Fish Taper worm= Diphyllobothrium latum, Dog Tape Worm= Echinococcusgranulosus
- What is the importance of the tegument and the protonephridia that occur in flatworms?
- Tegument - Provides the worm with external protection. ex: makes them impervious to digestive enzymes, this is important to a parisidic worm that lives in the gut of its host.
- Protonephridia - excretory or osmoregulatory organs closed at the inner end. Served as an early model fof the kidney.
- Where particular habitat and food preferences do the freshwater planaria prefer?
Spring fed Springs-Mainly carnivorous - Live or dead - small crustaceans, nematodes, rotifers, and insects.
How are the turbellaria able to reproduce asexually and sexually?
- Asexually- a. fission - constrict behind the pharynx and seperate into two animals
b. regeneration - Sexually - monoecious (both sexes, hermaphroditic), cross fertilization
- Illustrate and describe the life cycle of the human liver fluke, Clonorchis sinensis.
eggs containg complete miracidium are passed out in feces into water.
Eggs hatch after being eaten by snail, (Parafossarulus).
Miracidium to Sporocyst to Redia inside snail.
Redia go into liver of snail and develop into Cercaria- they escape into water and then bore underthe scales into the muscles of fish.(Cyprinidae family)
Human eats raw or undercooked fish and ingestes cysts from fish muscle.
cyst dissolves in dissolves in intestine. Young flukes migrate up bile duct where they become adults. Adults reside in liver.
In what places in the world are these human liver fluke parasites prevelent?
China, Southeast Asia and Japan
What are some of the animals that the human liver fluke may adversly affect?
Cats, Dogs, Pigs and Humans
Name three species of parasites that cause problems for humans and schistomiasis?
S. mansoni, S.japonicum, S.haematobium
What are some of the effects that Schistosoma have on humans?
- Eggs from S. mansoni and S. japonicum in the intestinal wall cause ulceration,abscesses, and bloody diarrhea with abdominal pain
- Eggs from S. haematobium causes ulceration of the bladder wall with bloody urine and pain on urination
- Eggs are often swept back to the liver and other organs by blood stream and cause cirrhosis and a fibrotic reaction that interferes with liver function.
* Can also cause brain damage, liver enlargment and bladder inflamation
What causes swimmers itch, what is the definative host and what problems does this cause in humans?
Schistosomes in Northern U.S. lakes.
Hosts are birds.
Causes a skin rash, more an annoyance than a serious threat.
Immune system destroys cercariae, they release allergentic substances causing itching. Human is dead end for this fluke
what species are “lung flukes” and how may humans get these flukes?
Species=Paragonimus
Host= humans, pigs and rodents
Eating uncooked freshwater crabs, eggs are then coughed up in sputum. Causes respiratory symptoms, breathing difficulties, and chronic cough. Fatal cases are common
Describe some of the unusual places that the monogenea may be found?
These are external parasites of fish found especially in gills, but a few are found in bladders of frogs and turtles
How may humans get beef or pork tapeworms? Which of these is more dangerous to man? What precautionary measures should humans take in order to prevent getting these parasites?
Eating undercooked or raw meat.
Pork is more dangerous.
Cook your meat.
