Groups of helminths (Eukaryotes ch)

Question 1

Trematodes (flat)

Answer 1

• Flukes
• • flat, leaf-shaped body
• Named for type of tissue they infect (ex: lung fluke)
• Not much of digestive system
• Absorb nutrients through their skin
• Dioecious

Question 2

Cestodes

Answer 2

• AKA tapeworm
• Small intestinal parasites
• Symptoms: eating food but not getting hungry, weight loss
• Obtained by eating undercooked meats
• Eggs consumed by grazing animals
• Segments break off into their own words (like cutting up a starfish)
• Taenia = genus

Question 3

Pinworms (roundworms)

Answer 3

• Egg-infective nematodes → person gets infected with the egg, egg hatches inside body, and develops into worm
• Found in large intestine
• Female crawls out of anus and can contaminate clothing and bedding
• Ascaris = genus
• Over 1 billion people are thought to be infected worldwide
• Dx: gram sticky tape method

Question 4

Hookworms (roundworms)

Answer 4

• Larval-infective nematodes → the egg is already hatched before the worm is in the body; the larvae infects people
• Eggs are excreted in feces and eggs hatch in the soil; larvae crawl in soil and infect people by penetrating the skin
• Penetrate through skin, end up in bloodstream, to end up in the lungs where they get coughed up in the sputum, sputum gets swallowed, and they end up in intestines again
• Heartworm is a hookworm infection

Question 5

Helminths reproduction

Answer 5

• Dioecious → separate males and females
• Monoecious → hermaphroditic (testes and ovaries)
• Location of reproductive organs are usually positioned in a way that they can fertilize themselves
  (2 worms can fertilize each other simultaneously)

Question 6

Platyhelminthes

Answer 6

Flatworms
ex: trematodes, cestodes

Question 7

Nematoda

Answer 7

Roundworms
ex: pinworms, hookworms