Chapter 14: Phylum Platyhelminthes Flashcards
Platyhelmithes are the ________ animals with bilateral symmetry. Their _______ is well defined. They are __________. They are also highly specialized_______.
simplest, mesoderm, triploblastic, parasites
What are the two major evolutionary advances ? (2)
-Cephalization - concentration of sense organs in anterior region
-Primary Bilateral Symmetry
I> body can be divided along only ONE plane of symmetry to yield two mirrored images of each other.
I> active, directed movement most efficient with an elongated body form with anterior, posterior, dorsal and ventral sides.
Platyhelminthes are Acoelomates meaning>
space between the epidermis and digestive cavity?
atypical acoelomates>
- have only one internal space, the digestive cavity
L> between the epidermis and digestive cavity is filled with parenchyma
-no digestive cavity!
Are Platyhelminthes acoelomate Protostomes or deuterostomes ?
Protostomes! their mouth develops first via blastopore !
Some platyhelminthes are _______; others are _____.
The parasitic clades share an external body covering called a ___________. (also called ______)
free-living, parasitic, syncytial tegument, neodermis
What are the four classes of Platyhelminthes?
Turbellaria, Trematoda, Monogena and Cestoda
Class Turbellaria are mostly___________. Habitat wise they are mostly _______ dwellers in ________ or ________.
Freshwater planarians are found in? (3) Terrestrial flatworms are limited to ____________. (2)
All members of monogena and Trematoda and Ceatoda are ______?
- free-living forms, bottom, marine, freshwater
- freshwater planarians are found in streams, pools and hot springs
- terrestrial are limited to moist places
Epidermis and Muscles?
Most have cellular ________ on a basement membrane. Rod shaped ________ that swells and form a protective mucous sheath.
- ciliated epidermis, rhabdites
Most turbellarians have dual-gland adhesive organs.These are?
- viscid gland cells which fasten microvilli of anchor cells to substrate.
- secretions of releasing gland cells provide a quick chemical detachment
Some turbellarians and others in this phylum have a Syncytial epidermis which is ?
-nuclei are not separated by cell membrane !
Those that are not turbellarians lack _______ and have a ______
cilia and have a tegument
Under the basement membrane there are what??(hint muscles) (3)
muscle fibres which run circularly, longitudinally and diagonally
Parenchyma cells fill spaces in the body which are mostly what?
non contractile portions of muscle cells
Nutrition and Digestion??? Cestodes have no _________ system.
Others in this phylum have a ______, _____, and ______.
In planarians the ________ may extend through the ventral mouth.
digestive, mouth, pharynx, intestine, pharynx
The intestine has how many branches?
three! one anterior and two posterior
The gastrovascular cavity is lined with what type of epithelium?
columnar!
Characteristics of the mouth of trematodes and monogeneans? (3)
- opens?
- pharynx?
- intestine?
- opens near the anterior end
- pharynx is not extensible
- intestine ends blindly, varies in branching
Planaria are carnivorous and detect food via ___________.
Food is trapped in ______________ from glands and _______.
They wrap themselves around prey
They extend the ________ to suck up bits of food.
chemoreceptors, mucous secretions, rhabdites, proboscis
Monogeneans and Trematodes?
-Feed on what? (3)
-Proteolytic enzymes from the intestine are secreted for _______.
-Phagocytic cells in gastrodermis complete digestion at ________ level.
-Undigested food is egested out via _______.
Cestodes rely on the host’s ____________. They absorb the _______ nutrients.
- host cells, cellular debris, and body fluids
- extracellular digestion
- intracellular
- pharynx
- digestive tract, digested
Protonephridia?
- flame cell?
- excretory system occurs how?
- osmoregulation?
- osmoregulation
- beating flagella drive fluids down collecting ducts
- wall of the duct beyond the flame cell bears folds or microvilli to reabsorb ions and molecules
- metabolic waste is removed via diffusion across the cell wall
- collecting ducts join and empty at nephridiopores (mostly for osmoregulation…therefore absent in marine turbellarians)
Marine Turbellarians lack Protonephridia b/c they have no need to expel _____?
excess water
Monogeneans have two excretory pores. Location of each?
- open laterally near anterior end
- flame cell protonephridia present also in the parasitic taxa.
Ducts of tematodes open into ___________ that opens to a terminal pore.
excretory bladder
Cestodes have two main excretory canals. Located?
one on each side.
metabolic waste is removed largely by diffusion through the body wall.
