Chapter 10 Flashcards
What is physiologically different about cestodes, what groups are they in
they can get really long, tapeworms, Platyhelminthes
What habitat do ADULT cestodes live in
vertebrate intestine, gut lumen, bile duct, gull bladder or pancreatic ducts
What are the major features of cestoda
adults are endoparasites, no gut at any stage, larva called hexacanth
What are cestode larva like
small with six hooks, arranged in 3 pairs
What are the 3 regions of adult tapeworms
scolex, neck, strobila
What is at the neck region of tapeworms
where the proglottides are budded off,
What is the strobila made of
maturing proglottids
Why is it important that tapeworms don’t have guts
the external surface of the parasite needs protection, locomotion and sensory uses
What is the tegument of tapeworms
external covering, naked cytoplasmic layer syncitium, similar to intestinal mucosa, for absorption
How do tapeworms increase their surface area
microtriches, folds that increase area x20
How do tapeworms digest if they dont have a gut
rely on digestive enzymes of hosts, transport and uptake nutrients through tegument
What dietary requirements do tapeworms have
need carbs, only glucose or galactose,
What are the 3 types of scolex found in tapeworms, what end are they on
anterior end, acetabulate, bothriate and bothridiate
What structure do acetabulate have
suckers,
penetrative-moves down into base of villi
non- enclose villi
What structure do bothriate have
pair of shallow sucking grooves-bothria, can form tubes
What structure do bothridiate have
4 leaf outgrowths called bothridia
What type of excretory system do tapeworms have
flame cells that open into collecting vessels
How do tapeworms regulate water
osmoconformers, do not regulate body volume, nerve net under tegument and sensory nerve endings keep them hypotonic
Explain how cestode nervous systems work
groups of muscle fibers get input from an excitatory nerve (contraction) and inhibitory nerve (relaxation), neurotransmitter amino acid glutamate excitatory, acetylcholine inhibitory
Explain resting potential and action potential for cestodes
resting K+
action Ca+/ for humans its NA+
How does paraziquantel kill tapeworms
opens the calcium channels causing worm to die in contracted state.
