Flatworms 1 Flashcards
two major evolutionary advantages
cephalization
primary bilateral symmetry
use of longitudinal, circular and diagonal muscles
locomotion
what organ do they not contain?
kidney
lack gut cavity
acoelomate
digestive system
mouth-tube like pharynx- sack like gut (incomplete)
aceolomorphs have a true brain (T or F)
F- lacks a true brain
what are the diffused system of anterior neutrons connected to?
radially arranged nerve cords
crown of ciliated tentacles
lophophore
what are lophophores used for?
- efficient feeding device
- respiration (increase surface area to gas exchange)
what are prototroch used in?
swimming and feeding
free swimming, feeding, ciliated cells in from of mouth
trochophore
turbellaria classifications
- free living
- digestive tract present
trematoda classification
- parasitic
- internal
- digestive tract present
monogenena classification
- parasitic
- external
- digestive tract
cestoda classification
- parasitic
- internal
- 2° loss
locomotion of turbellaria (3)
- ciliated ventral surface
- subtly muscular contraction
- dual-gland adhesive organs
paired viscid cells
produce adhesive secretions that attach anchor cells to substratum
anchor cells
bear strain of attachment and allow subtle muscular contractions to pull the animals
pedal wave
muscular contraction
releasing cell
secretes chemicals that release anchor cell attachment
what does a flagellar beat create in terms of osmoregulation?
negative pressure and draws fluid in through mesh
cellular interdigitation between flame cell and terminal tubule cup
mesh
excretory pores
nephridiopores
ocelli cells
for light detection
statocyts
for equilibrium
rheoreceptors
for sensing water flow
auricles
ear-like lobes on the side of the head, tackle and chemoreceptive
proboscis
used to suck up food
adaptations for parasitism (4)
- penetration glands
- glands to produce cyst material
- hooks and suckers for adhesion
- increased reproductive capacity
- dorsoventrally flattened
- leaf shaped
- syncytial tegument
trematode
monogenean (fish flukes)
mainly ectoparasites
simple life cycle
single host
digenean (mammal flukes)
complex life cycle
at least 2 hosts
(mollusc, vertebrate)
excretory system of adult digenea
ciliated cells extending into excretory tubules
nervous system of digenean adults
present, difficult to visualize
reproduction of digenean adults
hermaphroditic
- 5 developmental stages
- 2+ intermediate hosts
- high 1st intermediate host specificity (only)
- adulthood only achieved in a definitive host
digenean life cycle parasitic strategies
digenean location of adults
usually parasites of vertebrate animals
digenean location of larvae
free-living or infect (in)vertebrates
where are schistosome (blood flukes) found?
veins, intestine and urinary bladder
what is the infective stage of schistosoma (swimmers itch)
carcariae (larvae)
monogenean life cycle
1 egg= 1 adult
- no intermediate hosts
- autoinfection may be possible
- high specificity for definitive host
oncomiracidium
ciliated larvae
- has eyespots
- rudimentary digestive system
- opisthaptor
opisthaptor
ectoparasites that hang from the host
what hosts do tapeworms require (2)
definitive and intermediate
tapeworm morphology
torso-ventrally flattened
-lack a head and gut
scolex
attachment to host
-contains hooks
neck of tapeworm
zone of proliferation (behind scolex)
strobila (tapeworm)
chain of reproductive units
mature proglottids
mature reproductive organs
gravid proglottids
contain eggs in the uterus
microtriches
small projections covering the surface of cestodes
-increases surface area for food absorption (no digestive system- parasitic)
commonly occurs in eyes or the brain blindness
cysticercosis
