Phylum Platyhelminthes:
the Flatworms
Platyhelminthes Vocabulary
Use the blue modern bio textbook to do these on your grid. Color should
be on front. It doesn’t matter how you write the back. Remember to
complete your squares and # them correctly on the back.
1. Pharynx
2. Flame Cell
3. Cerebral ganglion 4. Eyespot
5. Fluke
6. Tegument
7. Primary host
8. Scolex
9. Cyst
10. Proglottid
11. Schistosomiasis 13. Strobila
12. Intermediate host
Taxonomy
Kingdom: Animalia
Phylum:Platyhelminthes (Plat = flat)
Class Turbellaria
Class Trematoda
Class Cestoda
Intro to Flatworms
http://www.youtube.com/watch?v=w0QzSYQGsnA
http://www.youtube.com/watch?v=ol5w-RlDuQ4
Characteristics of Flatworms
• They are acoelomates
(they don’t have body
cavities)
• They have bilateral
symmetry
• Show cephalization
• Single opening to
digestive tract (pharynx)
– Protostomes
Characteristics cont.
• Simplest animals to have 3 germ layers.
• Triploblastic
• Because they are
flat, all cells are
close to the
animal’s external
surface.
• All flatworms
rely on diffusion
for:
• respiration
• excretion
• circulation.
Characteristics cont
.
Digestive System
• Most parasitic worms do not need a
complex digestive system…WHY?
• They obtain nutrients from foods that
have already been digested by their
host.
Excretory,
Nervous, and
Reproductive
Structures
of a Planarian
Ganglia
Nerve
cords
Excretory system
Flame Cells
maintain
water balance
Flame cell
and remove
Excretory tubule
waste
Copyright Pearson Prentice Hall
Ovary
Testes
Movement
• Free-living flatworms move in two ways:
• Cilia on their epidermal cells help them glide through the water and over
the bottom of a stream or pond.
• Muscle cells controlled by the nervous system allow them to twist and
turn.
*The development of directional movement is correlated
(works in relation) with cephalization.
-some members have light sensitive receptors in head region
called ocelli
-in other members there are chemoreceptors & balance
receptors that sense water movement (not all in head
region)
MOVEMENT
Review Questions
• 1. What phylum are flatworms part of?
• 2. What are the three classes of
flatworms?
• 3. What type of coelomate are flatworms?
Name and describe.
• 4. How do they breathe?
• 5. What type of cells remove waste?
Class Turbellaria
• FreeLiving
flatworms
– Examples
are
planarians
• Eat
protozoans
http://www.youtube.com/watch?v=Fq_aSR5FK0Y&fea
ture=related
Planarians – Nervous System
• Spade-shaped at the anterior end
• Have two, light-sensitive eyespots
– Can sense light, touch, taste, & smell
Planarians – Nervous System
• Have 2 clusters of
nerve cells or
ganglia to form a
simple brain
• Nervous system
composed of a
nerve net
Reproduction
• Sexual Reproduction
•
http://www.youtube.com/watch?v=5fx-YgcP8Gg
– Hermaphrodites
-Cross fertilize eggs
Asexual
Reproduction
by
Regeneration
Planaria regeneration pt 1
Planaria regeneration part 2
Class Trematoda
• Are parasitic
flukes
• Have suckers on
both ends
– to cling to host &
suck blood, cells,
& body fluids
• Can live inside or
outside of host
Liver Fluke
Class Trematoda
• Nervous and
excretory systems
like turbellarians
• Hermaphrodites
• Have complex life
cycles
– Require 2 hosts
Schistosome
FLUKE ANATOMY
Liver Fluke
http://www.youtube.com/watch?v=uFQw-MPcPr4
Example Schistosomiasis
• Disease caused by a parasitic blood
fluke called a Schistosome.
• Infects people in Asia, Africa, &
South America causing intestinal
bleeding & tissue decay that can
result in death.
http://www.youtube.com/watch?v=VnlYUe57Lr0&featur
e=related
Schistosomiasis
Schistosomiasis (video notes)
• Caused by blood fluke – Schistosome
• Infects blood vessels around the host’s bladder and reproduces
rapidly
• Excreted in the urine & can come in contact with skin
• Starts as eggs in freshwatergrows in snailwaterhuman
• Creates a red rash if eggs are lodged in the skin
• Massive buildup in tissue can cause cancer
• 200,000,000 world wide..many in Africa
• Snail-intermediate host
• Human-primary host
• If infected, you are susceptible to get worm again even after
treatment
• Unsanitary water – Global disease #4
• The flukes are attracted to the fatty acid in the skin
• Can go undetected for 20 years
Schistosomiasis
• http://www.youtube.com/watch?v=Hkqk5Ljc3ko
• http://www.youtube.com/watch?v=cS70xQ5OywI
• http://www.youtube.com/watch?v=kIwVRhvk2oM&feature=relat
ed
• http://animal.discovery.com/tv-shows/monsters-insideme/videos/inside-a-snail-fever-lab.htm
White Tail Deer Liver Fluke
http://www.youtube.com/watch?v=NXNrsJlhrFk
Fluke Case
Japanese Lung
Japanese Lung Fluke
• Burrows into lung tissue and begins laying eggs
• Causes response of severe coughing up of blood and
release of body fluids
• Can be transmitted through raw crabs
• 80% of freshwater crabs in Asia are infected
• Causes inflammation in the lungs
• Blood that is coughed up is filled with eggs
• It is then reswallowed and excreted in feces
• Has many intermediate hosts
• Coughing up blood is a major sign of infestation
Review Questions (add to quizlet of continue to
record on your own paper if you don’t have access to technology.
•
•
•
•
6. Which class is made up of flukes?
7. Where can flukes live?
8. Why do they have suckers?
9. What does hermaphrodite mean?
What word describes this?
• 10. Id 4 organs flukes infect in humans.
Class Cestoda
• About 2,000
species
• Parasitic Tapeworms
• Long, ribbon-like bodies
• No digestive system
• Absorbs nutrients from host
• Hermaphrodites
• Can live in intestines of almost
almost all vertebrates
• Humans can harbor any of SEVEN
different species
• Tapeworm may cause: digestive
problems, weight loss, lack of energy,
and anemia (decrease in # of RBCs)
Different from other
flatworms because they…
• Lack eyespots and other light sensitive
structures
• Have no mouth/pharynx
– Instead they have hooks & suckers
• No Gastrovascular cavity
• No other digestive organs
SCOLEX of the tapeworm
Reproduction
•Proglottids are the segments that make
up most of the worm's body.
•Mature proglottids contain both male and
female reproductive organs.
Scolex
Tapeworm
Anatomy
Young
proglottids
Mature
proglottids
Uterus
Zygotes
Testes
Ovary
Reproduction cont
• Mature proglottids are released in
excrement (feces).
• Eggs are ingested by grazing animals
• Eggs hatch into larva
• Larva infect muscle tissue of animal
and form cysts
• Humans can become infected by
eating undercooked meat.
Tapeworm life cycle
Pork Tapeworm
Pork Tapeworm Extra Notes
• Can get cysts in brain from pork tapeworm  causes
seizures, coma, hallucinations, death
• 2 hosts: pig & human
• 60% of patients with PT have cysts in brain
• 6% of population has PT (sanitation issues)
• If you eat undercooked pork, you get the worm in your
intestines
• If you eat eggs in feces, you get cysts in tissues
• Albendozole – medicication given to starve the worm
• 50 million people world wide people infected –Mexico,
South America, India, & Carribean
• Leading cause of epileptic seizures—pork tapeworm
• Causes swelling in brain – Encephalitis
TAPEWORMS
• http://www.youtube.com/watch?v=txSi
ApFzaZE
overview
• http://animal.discovery.com/tvshows/monsters-inside-me Pork
Tapeworm
• http://animal.discovery.com/tvshows/monsters-inside-me/videos/porktapeworm-in-brain.htm
End of PP. review questions.
5. How do livestock ingest tapeworm
eggs?
6. Where do tapeworm larvae form cysts?
7. Cysts can survive in _____ or
________ meat.
8. Where does the tapeworm attach
itself?
Platyhelminthes
REVIEW QUESTIONS
Flatworms are the simplest animals to have
a. two germ layers.
b. bilateral symmetry.
c. radial symmetry.
d. two openings in the digestive system.
An individual that has both male and
female reproductive organs is known as
a. turbellarian.
b. proglottid.
c. hermaphrodite.
d. parasite.
The function of flame cells in
flatworms is to:
a. digest food and move it to various
parts of the body.
b. detect the presence of chemicals in
the surroundings.
c. remove excess water and metabolic
wastes
d. move reproductive cells into position
for fertilization.
A flatworm that lacks a digestive tract is
the
a. planarian.
b. free-living flatworm.
c. tapeworm.
d. fluke.
Turbellarians differ from most other
flatworms because they
a.
b.
c.
d.
live freely on land.
live freely in fresh and salt water.
are marine parasites.
are land-dwelling parasites.
6. The eyespots of a planarian
can be found at the _.
• Base of the organism
• Anterior end of the organism
• Posterior end of the organism
• In the gut
7. Which of the following is a
parasitic flatworm that causes
inflammation in the lungs?
• Planarian
• Fluke
• Tapeworm
8. _ on the epidermal cells of
flatworms help them glide &
move.
• Flame cells
• Muscle cells
• Cilia
9. What major organ in a
human is able to regenerate?
• Heart
• Brain
• liver
10. What flatworm is aiding in
the research of stem cells?
• Fluke
• Planarian
• Tapeworm
•
11. Which of the following is
NOT a class of
Platyhelminthes?
Cestoda
• Agnatha
• Trematoda
• Turbellaria
Foldable
1. Take a sheet of
paper and cut in half.
2. Lay one sheet on the
other and offset by
~ 1/2 inch.
3. Fold in the middle to
form 4 tab booklet.
4. Staple the top.
1
2
3&4
1. Label the tabs as
shown.
2. Under each tab List
the following and
answer for each:
1.
2.
3.
4.
5.
6.
7.
8.
Example:
Coelom:
Symmetry:
Germ Layers:
Digestive System:
Nervous System:
Reproduction:
Habitat:
Phylum
Platyhelminthes
Class Turbellaria
Class Trematoda
Class Cestoda