Platyhelminthes Flashcards
The mesodermal space is filled with muscle fibers and loose tissue called __, instead of a cavity
parenchyma
What class of platyhelminthes
possess a ciliated epidermis, which is an outer layer of cells covered with cilia (tiny hair-like structures)
Class Turbellaria
The mouth of free-living flatworms is typically located either at the
anterior end (front) or mid-body on the ventral surface (underside)
Free-living flatworms have a — , which means they can extend this muscular structure out of their body to capture food.
protrusible pharynx
What is the feeding behavior of Class Turbellaria
Carnivores: Some free-living flatworms actively prey on small invertebrates.
Scavengers: Others scavenge on dead animals and detritus (organic matter)
What class of platyhelminthes
free-living flatworms
Class Turbellaria
What class of platyhelminthes
ciliated epidermis
Class Turbellaria
Turbellarians are distinguished by
- the presence or absence of gut
- pattern of branching of the gut,
- type of pharynx
observes “negative phototaxis”
dugesia sp.
trematoda also called
flukes
What class of platyhelminthes
Has a cuticle covering its body
Class Trematoda
What class of platyhelminthes
Presence of 2 oral suckers for attachments, located at
Anterior oral sucker
For attachment and feeding
Ventral sucker (posterior acetabulum)
Class Trematoda
What class of platyhelminthes
Lacka opisthaptor (attachment organ) of monogenean flukes
Class Trematoda
Liver fluke
Fasciola hepatica
Bloodfluke
Schistosoma sp.
Human liver fluke
Clonorchis sinensis
Lung fluke
Paragonimus spp.
Intestinal fluke
Fasciolopsis buski
three species in schistomiasis
S. mansoni
S. haematobium
S. japonicum
Life cycle completed in two hosts
Water snail (intermediate host)
Humans (definitive host)
Fasciola hepatica and Schistosoma
Life cycle completed in three hosts
Water snail and fish (intermediate host)
Humans (definitive hosts)
Clonorchis sinensis
life cycle of trematodes
Egg hatches into miracidium, which swims and enters the first intermediate host (snail).
Inside the snail, it turns into a sporocyst and then rediae, which give rise to cercariae.
The cercariae leave the snail and become metacercariae, waiting to infect the definitive host when they are eaten.
In trematodes life cycle, what is its form before entering the intermediate host?
miracidium
In trematodes life cycle, what is its form before leaving the intermediate host?
cercariae
In trematodes life cycle, what is its form before entering the definitive host?
metacercariae
Free-swimming larva
After hatching, it finds and penetrates the first intermediate host (IH), usually a snail.
Once inside, it discards its ciliated covering to begin the next stage
miracidium
Sac-like form inside the first iH
sporocysts
possess tail for swimming;
considered as juveniles
cercariae
Common in bile ducts of sheep and other ruminants causing liver rot
Fasciola hepatica
Swimmer’s itch
Schistosome Dermatitis
storage of sperm after cross fertilization with anotherfluke
seminal receptable
carries sperm from testes to vas deferens
vas efferens
transfers sperm from testes to seminal vesicle
vas deferens
Adult stage lives in bile ducts
Clonorchis sinensis
carries sperm posteriorly from testes to vesicles for storage
vas deferens
regulation of internal fluid content of planarians
protonephridia
schistosomiasis commonly known as
bilharzia or snail fever
names and locations of three species of schistosomes
S. mansoni - large intestine
S. haematobium - urinary bladder
S. japonicum - small intestine
cestoda also called
tapeworm
beef tapeworm
Taenia saginata
pork tapeworm
Taenia solium
dog tapeworm
Taenia pisiformis OR
Echinococcus granulosus
fish tapeworm
Diphyllobothrium latum
describe tapeworms in respect from the preceding classes
cestodes, or tapeworms, have long, flat bodies composed of a scolex or proglottids
lack digestive system
What class of Platyhelminthes is this?
Lack sensory organs except for modified cilia that are sensory endings on the tegument
Class Cestoda
In class cestoda, these greatly enlarge the surface area of the tegument
Microtriches
T/F: tapeworms can fertilize their own eggs.
trueeee
largest of all human cestodes
D. latum
What class of platyhelminthes is this?
adult body covered with synctial tegument w/o cilia
Monogenea
What class of platyhelminthes is this?
External parasites of many fish, especially on gills, but a few are found in bladders of frogs and turtles
Monogenea
What class of platyhelminthes is this?
Generally cause little harm or damage to host
A problematic pathogen in crowded fish farming
Monogenea
Larval stage of Taenia saginata
oncosphere
Differentiate between the digestive processes of free-living and parasitic flatworms.
Free-living flatworms typically have a complete digestive system with a mouth and pharynx for capturing food, while parasitic flatworms may have a more simplified or absent digestive system, absorbing nutrients directly from their host.
How do the reproductive strategies differ between Monogenea, Trematoda, and Cestoda?
Monogenea: Mostly monoecious (hermaphroditic) and reproduce sexually.
Trematoda: Mostly monoecious, but some, like Schistosoma, are dioecious.
Cestoda: Primarily monoecious, producing both eggs and sperm within each proglottid.
monogeans have specialized attachment organ called
ophistaphor
Free-living, ciliated epidermis, simple or branching gut, carnivorous or scavenger.
turbellaria
Parasitic, complex life cycles with multiple hosts, two suckers, hermaphroditic, cuticle.
trematoda
Ectoparasitic, single host, opisthaptor for attachment, hermaphroditic.
monogea
Endoparasitic, no digestive system, scolex for attachment, segmented proglottids, hermaphroditic, complex life cycle with multiple hosts.
cestoda
in 3 classes of neodermata, what is the 2 features they share?
- loss of rhabdites
- syncytial tegument
how does the adhesive organ in neodermata differ from each other?
trematoda: ANTERIOR adhesive organ
cestoda and monogea: POSTERIOR adhesive organ W/ HOOKS
Secretions of the [1] apparently fasten microvilli of the anchor cells to the substrate, and secretions of the [2] provide a quick, chemical detaching mechanism.
viscid gland cells
releasing-gland cells
The term syncytial means that –
many nuclei are enclosed within a single cell membrane
The tegument’s shared presence among the parasites is the basis for uniting trematodes, monogeneans, and cestodes in clade [..]
Neodermata
Theese 2 classes graze on host cells, feeding on cellular debris and body fluids. The mouth of THESE usually opens at or near the anterior end of their body into a muscular, nonextensible pharynx
Posteriorly, their esophagus opens into a blindly ending intestine, which is commonly Y-shaped but may be highly branched or unbranched, depending on the species.
trematodes and monogeneans
Because [what class] have no digestive tract, they must depend on host digestion, and absorption is confined to small molecules from the host’s digestive tract.
cestodes
[what class] usually have two excretory pores opening laterally, near the anterior.
Monogeneans
In [what class] there are two main excretory canals on each side that are continuous through the entire length of the worm
cestodes
what species: a marine polyclad turbellarian.
Pseudobiceros hancockanus
[Turbellaria] Order Polycladida’s unique feature
intestine with many lateral branches
[Turbellaria] Order Tricladida’s unique feature
three branched intestines
3 features that all platyhelminthes share
lamellate rhabdites
endolecithal eggs
mehlis’s glands
Multinucleated layer that replaced the original epidermis after larval development
syncytial tegument (neodermis)
Mucus secreting structure that prevent leaking of water (prevent drying of worms) and aids in protection
Rhabdites
Swell and form a protective mucous sheath around the body when discharged
Rhabdites
Surface of the epidermis of free living has …
Dual-gland adhesive organs
The mesodermal space is filled with muscle fibers and loose tissue called parenchyma, instead of a cavity
parenchyma cells
functions of parenchyma cells
- Structural support,
- Nutrients storage and distribution
- Contains totipotent stem cells
In general, platyhelminth digestive systems include a […]
mouth, a pharynx, and an intestine (gastrovascular cavity)
digestion of parasitic organisms
Trematodes and Monogeneans have blind sac
Cestodes have no digestive tract
has hooks and suckers that allow the tapeworm to attach to the intestinal wall of the host.
scolex
Each containing reproductive organs.
proglottids
Responsible for osmoregulation and excretion of waste
protonephridia
Cup-shaped
Cells within protonephridia which filters excess wate
flame cells
The most primitive flatworm nervous system, found in some turbellarians
Resembles the nerve net of cnidarians
Subepidermal nerve plexus
the nervous system of platyhelminthes have one to five pairs of
Longitudinal nerve cords
Light sensitive eye structure that measures light intensity and helps in correcting orientation and navigation
ocelli
Corrects balance (gravity)
Equilibrium
statocysts
Responsible for sensing direction of water currents to find food and avoid predators
rheoreceptors
reproduction of platyhelminthes
asexual - fission
sexual - copulation, fertilization, development
are platyhelminthes monoecious or dioecious?
monoecious
