Planarian
A.k.a. Slimy
Slimy Classification
Phylum :
Platyhelminthes
(Flatworms)
Class:
Turbellaria
Slimy traits
¾ Lifestyle:
free-living
¾ Habitat :
fresh water
¾ Hides under rocks,
leaves, & debris
to avoid light & predators.
Slimy Traits - Feeding
• Feeding pattern :
carnivore / scavenger
• In captivity : egg yolk,
liver
Slimy parts
1. pharynx
2. GVC
3. eyespot
(ocellus)
4. auricle
Functions of Slimy parts
1. Pharynx
- feeding
2. GVC
- digestion (enzymes)
3. Eyespots (ocelli)
-photo-detection
4. Auricles
- chemo- & thigmo-reception
?s 1-9
Slimy Traits - Response
Brain?
Anterior Ganglia
Cephalization?
Yes
Nervous system?
Two longitudinal nerves
with cross bridges
Slimy Traits - Response
Sensory organs?
*Chemoreceptors
*Thigmoreceptors
*Ocelli
*Statocysts
Slimy Traits - Movement
Means of locomotion:
1. Cilia
2. Longitudinal Muscles
3. Circular Muscles
4. Slime
Slimy Traits - Reproduction
• Capable of
regeneration
• Record #
of cuts
that
produced
regeneration
= 56
Planarian Regeneration Patterns
Planarian Regeneration Patterns
Why do we care that Slimy is the
King of Regeneration?
¿How does he do it?
If we figure this out,
can we figure out how to grow back
human parts?
Flatworm Regeneration Research
Alejandro Sanchez Alvarado, at the Howard
Hughes Medical Institute is researching
flatworm regeneration.
Here’s the scoop:
1. Studying Slimy "because they have a
large amount of stem cells in their bodies,
and they are renowned for their
regenerative ability.”
What is a stem cell?
2. Stem cell =
¾ undifferentiated cell
¾ can produce offspring cells of many
different types, such as blood cells or
kidney cells.
Implications of Slimy research
3.What if we could use stem cells to
regenerate damaged or missing organs?
Slimy can do it !
Not there yet…
4. We aren’t even close at this point
?s10-16
Slimy Signs off
I’m a little cross-eyed
flatworm!
See you next
time you go for
a swim!