Invertebrates Flashcards
Multicellular invertebrates are divided into (how many?) groups based upon the number of germ layers formed during embryogenesis.
Two groups
(????????) are groups of cells that behave as a unit during early embryonic development and give rise to distinctly different tissue systems in the adult.
Germ Layers
What are the two germ layers Diploblastic animals have?
Ectoderm (outermost layer)
Endoderm (innermost layer)
What are the three germ layers Triploblastic animals have?
Ectoderm
Mesoderm
Endoderm
Triploblastic animals are further classified by their internal body cavity
Acoelomate:
No internal body cavity
Triploblastic animals are further classified by their internal body cavity
Pseudocoelomate:
fluid-filled cavity between endoderm and mesoderm
Triploblastic animals are further classified by their internal body cavity
Coelomate:
internal, fluid-filled cavity between endoderm and mesoderm, lined with mesoderm
What phylum does flatworms belong to?
Phylum Platyhelminths
What are 3 kinds of flatworms?
Tapeworms, flukes, and non-parasitic flatworms
What class does tapeworms belong to?
Class Cestoda
What class does flukes belong to?
Class Trematoda
What class does free-living, non-parasitic worms belong to?
Class Turbellaria
What is the cat (or dog) tapeworm called?
Taenia pisiformis
What system do tapeworms lack?
Digestive system
What is the best place in the body for a tapeworm to live?
Intestines
What is a scolex?
The head of the tapeworm
What 2 structures does the scolex have that helps it grab onto the mucosa of the intestines?
Suckers and Hooks
Tapeworms belong to what Class?
Class Cestoda
What is the term for a dog or cat tapeworm?
Taenia-pisiformis
The head of a tapeworm is called what?
Scolex
What does the Scolex contain?
Suckers and hooks
What are the segments of a tapeworm called?
Proglottids
What do the Proglottids contain?
Testes and ovaries
What are the 3 tapeworm diseases?
- TAENIASIS (Pork and Beef)
- CYSTICERCOSIS (Pork only)
- TAENIA-PISIFORMIS (Dog and Cat tapeworms)
What is Taeniasis caused by?
Pork or beef intestinal infections
What are the symptoms of Taeniasis?
It is usually asymptomatic, mild GI pain, but you may see the proglottids wiggling in the stool
What is Cysticercosis caused by?
Pork tapeworms
What are the characteristics of Cysticercosis?
- It is much more serious, even life-threatening
- The Tania egg is ingested by the fecal-oral route
- Larvae embed in any tissue (esp. muscle, brain, eye)
- Once ingested, the eggs hatch and invade.
What are the symptoms of the Dog and Cat tapeworms (Taenia-Pisiformis)?
Mild symptom of diarrhea and gas
How do flukes differ from tapeworms?
Flukes are non-segmented.
Where do flukes live?
Venuoles in humans
What characteristic of flukes causes damage in the human brain?
Their large number of eggs
What disease do they cause?
Granulomas, which are inflammatory lesions
Where can granulomas occur?
Many organs including the brain, spinal cord and liver.
Clonorchic sinensis (liver fluke) and the Fasciolopsis buski (giant intestinal fluke) belongs to what class?
Class Trematoda
What are the main parts of the clonorchic sinesis (liver fluke)?
Oral sucker Pharynx Intestines (cecum) Uterus Testes
What are the main parts of the Fasciolopsis buski (giant intestinal fluke)?
Mouth (for feeding)
Ventral sucker (for attachment)
Intestines (cecum)
Testes
Define Schistosoma mansoni
Female blood fluke:
- Ventral sucker (for attachment)
- Ovary
- Mouth (for feeding)
Define Schistosomiasis
- The blood fluke is called Schistostoma. “Schisto” means “split” and “soma” means opening.
- The male’s body is split into a gynecohoric canal; this is where the females live. The female is smaller and lives within the male her whole life.
- She lays thousands of eggs a day
What are the blood fluke diseases?
- Schistosomiasis
- Swimmer’s Itch
Characteristics of Schistosomiasis?
- Schistosomiasis kills 1-2 million people per year; it’s almost as bad as malaria. It is a tropical disease. It is also known as “Male menstruation” because there is a bladder fluke which causes hematuria (blood in the urine). When Napoleon invaded Egypt, his men got this disease and called it the Curse of the Pharaoh.
- Many people are asymptomatic, but the acute form (Katayama’s Fever) can occur weeks later, manifesting with fever, coughing, nausea, vomiting, diarrhea, hepatosplenomegaly, and eosinophilia (excess eosinophils, a type of white blood cell that responds to parasitic infections).
Where do the schistosomulae migrate to?
The veins
The females are smaller and live where?
inside the male
The Schistosomiasis deposit eggs inside where?
small venules
Where do the Schistosomiasis eggs move toward?
moved progressively toward the lumen of the intestine and are eliminated with feces or urine.
How is Schistosomiasis infection transmitted?
Human contact with water is necessary for infection by schistosomes. Skin penetration in required.
What are the symptoms of Schistosomiasis?
Katayama fever, granulomas (occasionally in brain or spinal cord)
Swimmer’s itch is the only schistosome disease found where?
USA
Swimmer’s itch is caused by?
A schistosome that should have a bird as a host, but humans can become an accidental host. An infected duck passes the eggs in the water. Humans who are swimming in late July and August are more likely to get this.
What happens to the organism since it cannot live in humans?
It dies under the skin after it penetrates it.
What does this cause?
An itchy reaction.
What is the treatment?
oral trimeprazine and topical cortisone (anti-inflammatory) creams.
What is the prevention?
rub your skin hard with a towel as soon as you get out of the water to prevent the worms from penetrating.
What are Class Turbellaria Invertebrates?
Free living flatworms (not parasitic)
What are characteristics of class Turbellaria invertebrates?
Planaria spp.
Pharynx
Eye spots (light sensitive)
Gastrovascular cavity
What is Phylum Platyhelminthes?
Flatworms: Tapeworms, flukes and non-parasitic flatworms
What is Phylum Nematoda?
Roundworms, hookworms and threadworms
What is Phylum Annelida?
Segmented worms
What is Arthropoda?
Ticks, mites and lice