Platyhelminthes Flashcards
What are the key evolutionary advances of Platyhelminthes?
Organs and bilateral symmetry
What is the common name of Platyhelminthes?
Flatworms
What kind of coelom does a flatworm have
ACoelomate
What is the boy description of a flatworm
Flat, non segmented.
Systems present in flatworms
Nervous, excretory, digestive
Symmetry of flatworms
Bilateral
Are flatworms cephalized
Yes
What does triploblastic mean
They have all three germ layers
Are roundworms triploblastic
Yes
Are flatworms triploblastic
Yes
Tegument
Outer non cellular covering of flatworms.
What lies beneath the Tegument?
The epidermis
What are the three types of muscles in flatworms
Circular longitudinal oblique
Where are the gland cells
In the epidermis
Do flatworms have a complete or incomplete digestive system
Incomplete
What is an incomplete digestive system
No way “out” aka no anus.
What is a complete digestive system.
One way in, one way out. Has an anus.
What are the digestive organs of a flatworm
Mouth pharynx intestines
What is the nutritional mode of flatworms
Mainly carnivores
What is excretion and osmoregulation
The waste and water releasing system
Protoneohridia
Means first nephridia, aka first kidney.
Flame cells
Flagellated cells that collect water
Weir
The network of Protoneohridia that form series of tubes that connect with nephridiophores to empty waste.
Nephridiophores
Holes that allow waste to be emptied
Ganglion
Collection of neurons found in the anterior end.
Longitudinal nerves
1-5 of them run from the ganglia down the length of the body. They are connected by transverse nerves in a ladder pattern.
How do flatworms respirate
Respirate through their skin.
Turbellaria
Planarians
Trematoda
Flukes
Cestoda
Tapeworms
Monogenea
Parasitic flukes
Planarian habitat
Mostly aquatic some on land
Are planarians parasitic
No, all non parasitic
What is special about the epidermis of planarians.
They have a ciliated epidermis with gland cells that secret mucous.
What does the mucous do for the planarian.
It creates more friction for the movement of the planarian.
Circular muscles
Contract to become long and skinny
Longitudinal muscles
Shorter and girthier
Oblique muscles
Allows for twisting and turning
Auricles
Sense chemical smell and taste, super sensitive to touch.
When does mucous secretions increase in the planarian?
They increase 5x when prey is sensed.
Why do mucous secretions increase?
To help trap prey.
What happens to the undigested food in the intestines.
It is regurgitated through the mouth.
Ocelli
Light sensing
Auricles
Sense chemicals smell and taste
Fragmentation/fission
Planarian constricts behind the pharynx and splits into two.
Why does fissioning occur
Reduced population density
Regeneration
Planarian regrows missing parts
Are planarians monoecious or dioecious
Monoecious
Genital pore
Pore that provides access to the genitals.
Endolecithal
Yolk is inside the egg with the zygote.
Which flatworm has Endolecithal eggs
Planarians
Mode of nutrition flukes
Parasites
Who has thick teguments and suckers?
Flukes
Why is a thick Tegument an advantage?
Protests flukes from dangerous chemicals in the host body.
What adhesion organs do flukes have
Suckers and hooks
What do flukes feed on
Host cells, cell fragments, tissue fluids.
What is the nervous system of flukes?
Same as planarian.
Why do flukes not have special sensory organs?
They don’t hunt for prey they just attach to their host.
Intermediate host
Where parasitic organism is still not mature
Definitive host
Where parasitic organism lives while an adult.
What happens when two adult flukes meet?
They fertilize each other.
What adds yolk to the egg of planarians.
Vitellaria
Ectolecithal
Yolk is found outside developing embryo.
Miracidium
Tiny ciliated larvae inside the fluke egg. They lay dormant until eaten by an organism.
Sporocyst
Miracidium burrows into organisms tissue and becomes a Sporocyst.
Redia
Produced when sporocyst reproduce asexually.
Cercaria
Redia reproduces asexually creating the larval cercaria. (Which can swim)
Metacercarial cyst
Cercaria will transform into this. Host the larvae for an extended period of time.
What happens when the metacercarial cyst reaches the definitive host?
It exycyst (leaves cyst) and is an adult fluke.
Chinese liver flukes
Important to humans because it causes cirrhosis of the liver. Raw fish.
Blood fluke
Causes schistosomiasis, a blood fluke infection. Penetrate the skin of humans.
Tapeworms mode of nutrition
Parasitic
Who has well developed muscles, no special sense organs, and regular excretory and nervous system?
Tapeworms.
Scolex
Tapeworm head. Knob shape with suckers surrounding it, and ring of hooks at the anterior end.
How do tapeworms obtain and digest food?
Absorb it through their skin.
What covers the body of the tapeworm
Microtriches and microvilli. No external cilia.
How do microtriches aid in obtaining nutrients from the host?
Increase the surface area b
Strobila
Chain of proglittids that make up the tapeworm body.
Proglittid
Each is composed of reproductive organs.
Germinative zone
Area where new proglittids form
How are metabolic waste removed in tapeworms?
Diffused through body wall.
What kind of lecithal development do tapeworms have.
Ectolecithal
Gravid
Proglittid that is filled with eggs.
What is the key evolutionary advance of roundworms.
Pseudocoelomate
Name all pseudocoelomate phylums
Just roundworms.
Where are roundworms found
Everywhere
Nutritional mode of nematods
Everything except filter feeders.
What is the common name of nematoda
Roundworms.
Hydrostatic skeleton
Pseudocoel filled with water that is under high pressure.
What muscle do roundworms have
Longitudinal ONLY
How does pseudocoel help with circulation
Intersectional fluid allows molecules to move around body.
How does organ function get helped by pseudocoel
Fluid protects against organs getting smashed.
Body wall of roundworms
Thick cuticle layer
What is the thick cuticle made of
Collagen
What is beneath the cuticle
Epidermis
How do roundworms respirate
Diffuse through moist body wall.
Sensory papillae
Receive physical stimuli.
Where are sensory papillae.
Around the head and tail.
Amphids
Sensory organs that receive chemical stimuli.
Where are amphids found.
On the head.
Phasmids
Amphids but on the posterior.
Where is te makes general pore on roundworms.
On the posterior.
Penial spines
Copulatory spines that help attach male to female.
Ameboid sperm
Help sperm move against high turgor pressure of female.
Excretion and osmoregulation of roundworms.
Two lateral tubes running longitudinally. Water is let out excretory pore.
Ascaris
Found in horses and pigs. Enters host through improperly cooked meat. Causes gastrointestinal pain.
Hookworms
Burrows through host flesh. Causes anemia and delays in children.
Filarial worms
Live in lymphatic system. Cause elephantiasis.
Pinworm
Causes anal itching.
Trichina
Creates a nurse cell and causes muscle paralysis.
Nurse cell
Cell taken over by a parasite that stops producing for itself and feeds the parasite.
Roundworm classes
Adenophorea and secernentea
Mouth
Eating, where food enters.
Pharynx
Sucks the food in.
Intestines.
Where the food is extracellularly digested and absorbed.
Rectum
Where waste collects
Anus
Where waste leaves.
What are roundworms sperm lacking
Flagella
What is the female roundworms general pore called
Vulva
Where is the vulva found on the female.
In the middle of her ventral surface.
What does the cuticle help do
Keeps the strong turgor pressure in the roundworm from keeping them from blowing up.
What are the symptoms of elephantiasis.
Intense swelling rotting of the flesh
What level of organization are roundworms and flatworms on
The organ level
What is fencing
When two planarians fight to copulate
What is copulation
Release of the sperm
What special reproductive organ do planarians have.
Double penises
What do planarians put their eggs in.
Cocoons.
What is the genital pore
Where the sexual organs have access to the outer world.
How do planarians reproduce.
Stab each other with their penises until one consents to being impregnated.
Why do planarians not like being pregnant?
It’s rough for their bodies and can lead to death.
Do planarians fertilize each other?
No, only one gets fertilized.
What does the winning planarian do?
Creates an enzyme to eat up the sperm in its body.
What digestive organs do flukes have?
Mouth, pharynx, intestines.
What digestive organs do tapeworms have?
None.
What do flukes lack?
Ocelli
What does stomach acid do to fluke cyst?
It eats up the cyst that covers the lil fluke and wakes it up.
Are tapeworms monoecious or dioecious
Monoecious
Do proglottids have one or both kinds of sex organs?
Both, but not at the same time.
What sex does each proglottid become first.
Male.
What sex does each proglottid become second.
Female.
What happens to the gravid?
It reaches the end of the chain and falls off.
What happens when the proglottid dries out?
It releases eggs.
What happens when the tapeworm eggs are eaten.
They form cyst in the muscles of the host and wait to be eaten.
What happens when cyst are eaten by a definitive host.
They hatch and begin the adults life.
Examples of roundworms
Filarial worms, guinea worms, pinworms.
How do roundworms move.
One side of the body contracts muscles which causes the other side to bulge and stretch.
How many species of roundworms
12,000 known
How many speculated species of roundworms
500,000
Where do parasitic roundworms lay eggs.
In the feces of the host.
What is the major host of ascaris.
Pigs.
