11.3 Platyhelminthes Flashcards
Protostomes are…
- Triploblastic
- Blastores develop into mouth
- Anterior brain
- Ventral nerve cord
- Bilateria
Other name for Platyhelminthes?
Flatworms
Platyhelminthes - gut?
Blind
Body plan of platyhelminhes?
Planarian - head, eyespots (photoreceptors), auricles (chemoreceptors), highly branched digestive cavity
How do platyhelminthes take up O2?
Diffusion (highly flattened body): no respiratory or circulatory
True or false - some have no digestive cavity or mouth
True. They have a higly branched digestive CAVITY
Platyhelmintes - symmetry?
- Bilateral (because head)
Directed movement is linked to ….
Cephaliztion
What are the advantages of concentration of neurons and sensory structures at the anterior end?
- Enables directed motion and behaviour
- Senses encounter new environment first
Sensory structures of platyhelminthes?
- Mechanoreceptors
- Chemoreceptors
- Photoreceptors
Nervous system of platyhelminthes?
- Cerebral ganglion (concentratin of neurons, primitive brain)
- Longitudina nerve cords
Free living platyhelminthes?
Turbellaria (planarian - can regenerate body, anterior and always develop into a head, reproduce asexually by fission &sexually)
Parasitic platyhelminthes?
- Monogenea (ecto)
- Trematoda (endo)
- Cestoda (endo)
Monogenea?
- Ectoparasites, flukes = flat body with suckers (on fish gills)
Trematoda?
Endoparasites, flukes (primary - humans - and intermediate host - snail)
