Phylum Platyhelminthes

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Phylum Platyhelminthes
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Platyhelminthes

1. Flatworm
2. One body opening
3. Very simple Nervous Muscular Systems
4. May be Parasitic or Free living

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Planarian (Class Turbellaria)

• Free-living flatworm with
• Bilateral Symmetry
• Lives in freshwater
• Found under leaves rocks
• Feeds on dead or slow moving organisms

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6. Reproduction a. Sexually
Hermaphrodites Male Female Parts b.
Asexually Fission can regenerate body parts 7.
Nervous Sensory System a. Brain-like
Ganglion located in anterior region b. Nerve
cord to carry impulses c. Eyespots sense
light dark d. Sensory pits line sides of
head to aid in movement
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e. Cilia line body aid in
movement f. Flame cells remove excess
water nitrogenous wastes 7. Digestion Food
enters mouth solid wastes exit mouth a.
Mouth located in center of ventral
side b. Pharynx tube-like struture
which extends from mouth during
feeding-acts like a straw sucking
up food carrying it to the body
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Figure 273 Page The Anatomy of a Flatworm
Freshwater flatworms have simple ganglia and
nerve cords that run the length of the body. The
excretory system consists of a network of tubules
connected to flame cells that remove excess water
and cell wastes.
Head
Eyespot
Flatworms use a pharynx to suck food into the
gastrovascular cavity. Digested food diffuses
from the cavity into other cells of the body.
Eyespots in somespecies detect light.
Mouth
Pharynx
Most flatworms are hermaphrodites, having male
reproductive organs (testes) and female
reproductive organs (ovaries) in the same
organism.
Flame cell
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Tapeworm (Class Cestoda)

• Parasitic Flatworm
• Lives in the Intestines of Vertebrates
• Can grow up to 10 meters in length!
• Reproduction Hermaphrodites

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5. Flattened body is made up of individual
segments called Proglottid a. Each proglottid
is detachable b. Each proglottid may contain up
to 100,000 eggs c. Fall off when
full d. Released with wastes
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6. Head Region Scolex a. Surrounded by
hooks suckers to aid in attachment to
intestine b. Smallest section of worm c.
Proglottids grow out from scolex
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7. Life cycle a. Eggs hatch in intestines of
Intermediate Host (pig) b. Young worms
burrow into pig muscle c.
Secondary Host (man) eats undercooked/raw meat
contaminated w/ worm larvae cysts d.
Larvae hatch mature in intestines,
must live in intestines since they dont
have them e. Attach to intestines and soak
up digested food of host f. May
enter bloodstream infect other
tissues w/ cysts
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Flukes(Class Trematoda)

• Parasitic Flatworm
• Lives in Digestive System or Liver
• Feeds on cells, blood, body fluids
• Blood flukes
• Eggs are released in water from wastes of
  infected host
• Hatch into larvae
• Larvae enter snail where they develop reproduce
• Enter water again bore into skin of new host

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e. From blood, they bore into intestines where
they attach feed on blood 5. Liver
flukes a. Lodge in liver ducts of host b.
Block liver ducts which can cause liver damage
or failure
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Quiz 2 Flatworms IN
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• Planarians have ___ symmetry.
• a. bilateral b. radial c. assymetrical d.
  symmetry
• 2. Flatworms reproduce sexually, they are
  hermaphrodites, what does this mean? A.
  produce only sperm C. produce only eggs B.
  produce egg sperm D. none
• 3. A tapeworms body is made of individual
  segments called __ A. segments B. flame cells
  C. scolex D. proglottids
• The difference between planarians and tapeworms?
• a. planarians are parasites, tapeworms are
  freeliving
• b. tapeworms are parasites, planarians are
  freeliving
• c. both are parasites d. all the above
• 5. The function of ___ is to remove excess water
  wasteA. pharynx B. flame cells C.
  fission D. cysts