Platyhelminthes Flashcards
What is the literal meaning of Platyhelminthes?
(greek)
Platys (flat)
Helminthes (worm)
Flatworms
Body of the platyhelmintes
(think of the diagram)
Flatten dorsoventrally with a protuding mouth on its ventral side.
Describe its morphology
- Elongated
- no legs
- Bilateral symmetic
Platlyhelminthes are among the first animals to exhibit bilateral symmetry.
(true of false)
True
Cephalisation
(platlyhelmintes have this)
differentiation of head.
How many germ layers do platlyhelminthes have?
3 layers - Triploblastic
Name the 3 germ layers found in Platlyhelminthes
Endoderm,ectoderm, mesoderm
Discribe platlyminthes coelom
(what kind to they have?)
Acoelom. Do not have a fluid-filled body cavity
the mesodermal cells or mesenchyme consit of?
Parenchyma
What kind of organization do platlyhelminthes have?
Organ level grad organisation
which worm does not have a gut?
(starts with cest : and is a tape)
Cestoidea tape worms
What kind of guts do platyhelminthes have?
Incomeplete gut
describe the modes of life of the platyhelminthes
free-living and parasitic.
How many classes are there in platyhelminthes and name them.
- tapeworms; Cestoidea
- free-living flatworms;Turbellaria
- flukes-parasitic flat worms; monogenea
- flukes; Trematoda
describe turbellaria
- freeliving below stones and marine debris
- symbiosis with orthers
- have cilia on epidermal calls
What does the platyhelminthes digestive system include?
A pharynx
A mouth
An intestine
What is the two type of feeding do Platyhelminthes utilizie
Scavengers and carnivores
(small insects, crustaceans, nematodes)
How does turbellarian (planaria) detect food and food distance?
Chemoreceptors (food)
sensory cells on head (distance of food).
What type of animal requires osmoregulation?
(what habitat do they live in?)
Freshwater animals
Why does freshwater animals require osmoregulation?
Freshwater animals are hypertonic to their aquatic environments therefore need to osmoregulate.
What allows for turbellarians to live in fresh water?
(starts with P and rhymes with photo)
Protonephridia
What would happen to turbellarians if they had no protonephridia (flame cells)?
They would swell up.
What is the name of the first kidney in platyhelminthes?
Protonephridia
What does the flame cell have in it?
Cilia or flagella inside their cup-shaped body, that resombles a cell.
What are the holes that flame cells excrete their waste from?
(from the word protonephridia)
Nephridiphores
describe the osmoregulation and excretion in platyhelmintes.
The Platyhelminthes’ metabolic waste is partly eliminated through their protonephridia and body walls. This occurs mainly through their body wall. The protonephridia is their first kidney and is also known as a flame cell. The flame cells have cilia or flagella, which beat and transport fluid to the collecting duct, creating a negative pressure, which draws the fluid from the surrounding tissue to the Tubule. The tubule then is merged and opens outside of the body wall, and waste is eliminated from the mesenchyme to the nephridiphores. Microvilli are responsible for water absorption to keep bodily fluids at the correct or ideal concentration.
What does the nervous system consist of?
(6 THINGS. WHAT ARE THEY?)
- Eyespot (Ocelli)
- sensory lobe (Auricle)
- Subepidermal Plexus
- Brain (Cerebal Ganglia)
- Longitudinal nerve chord.
- Latteral branches
Where are the sensory cells connected to? Anterior or posterior?
Anterior end of the flatworm that interacts with the environment first.
Where are the nerve cells concentrated in the platyhelmintes
The cerebal ganglia (brain)
Auricles what are their function and where are they located?
At the side of the head of the tubellarians.
Have chemoreceptors concentrated in the auricles.
Eyespots what are they
have dark pigments that look like a iris of a human and helps them detect light.
(pigment cups).
Longitudinal nerve cords and latteral branches what do they do?
Responsible for most behavior.
What is another word for latteral branches?
Commissures
What gives the patyhelminthes its ladder structure
Combination of lateral branches (commissures) and the longitudinal nerve cords.
What are the forms of locomotion in platyhelminthes?
Swimming (muscle contractions) and crawwing (ciliated ventral side of the organism and the flatten surface helps the worm move by crawing).
