Lab 4 phylum platyhelminthes and body symmetry

body symmetry

bilateral

acoelomate body structure

no true body cavity (coelum)

platyhelminthe digestive system

incomplete, gastrovascular cavity

class turbellaria

free living flatworms (non parasitic) less than 5mm long

class turbellaria ecology

found in water

oral opening of class turbellaria

midventrally, opens into the gut via a pharynx that extends out through the mouth for feeding

class turbellaria digestion

both extracellular and intracellular (can range from simple sac to complex branched intestine)

auricles

earlike, chemosensory lobes that are "ear-like"

eyespots

black pigment that serves as light detectors to help orient the organism

class trematoda

liver flukes, endo and ectoparasites of both vertebrates and non vertebrates

what type of attachments do trematodes have

1 or more ventral suckers

one host

simple life cycle

multiple hosts

complex life cycle

tegument

living outer layer of the epidermis (the neodermis)

opisthorchis

the chinese liver fluke, of class tremetoda

primary/definitive host of opisthorchis

humans and domestic animals

miracidium

a free swimming ciliated larva that resembles a protozoan (so it will get eaten by its host)

first imediate host of opisthorchis

an aquatic snail

sporocyst

stage in the opisthorchis life cycle that contains many rediae

redia

stage in the opisthorchis life cycle that contains many cercaria

cercaria

escapes into the water from the redia to attach to the next host (a fish)

second intermediate host of opisthorchis

fish

metacercaria

cercaria boring into the fish host and form cysts

body plan of cercaria

larva have a tail and oral and ventral suckers to attach onto the gills of fish

host cycle of opisthorchis

water, free swimming miracidia enter snail, larvae develop in snails body, cercariae break out into water, attach to fish gills, infected fish eaten by humans, eggs released in feces eventually makes it back to the water

life cycle of opisthorchis

miracidium breaks out of capsule, into sporocyst, into rediae, into cercariae, into metacercarial cysts, into adult fluke which produce eggs in the capsules

what is the difference between the 2 trematoda parasites, opisthorchis and schistosoma?

schistosoma skips the first snail host stage

what long term disease can schistosoma cause

bladder cancer

what is class cestoda

tape worms

cestoda digestive system

no mouth or digestive tract as they are absorbing digested nutrients

scolex

head of the tapeworm

strobila

body of the tape worm, composed of numerous proglottids

proglottid

segments of a tapeworm

cysticercus stage of cestoda

the larval stage, found in muscle of tapeworms intermediate host

life cycle of beef tapeworm

eggs with larvae in grass, beef eats it, scolex attachs worm into muscle tissue, beef is eaten by humans

cephalization

brain and sensory information gathered in the anterior "head" region

dugesia tigrina

the flatworm we used in the experiment

how does dugesia tigrina react to light

negatively phototactic

eyespots

A

auricle

B

pharynx extended through the mouth

C

gastrovascular cavity

D

ovary

E

yolk gland

F

testis

G

sperm duct

H

pharynx

I

seminal receptacle

J

penis in genital chamber

K

genital pore

L

transverse nerve

M

ventricle nerve cord

N

brain

O

anterior valve

A

mouth

B

ctenidia (gills)

C

mantle (girdle)

D

foot

E

posterior valve

F

anus

G