Platyhelminthes

Polycladida

GVC with many branches

rhabdocoela

simple sac like GVC

tricladida

3 branched GVC

neodermata

parasitic

trematoda

parasitic

cestoda

tapeworms

symmetry in flatworms

bilateral

development of head

cephalization

number of derm layers

3

type of GVC

incomplete

Do they produce both eggs/sperm? yes/no (type)

yes (monoecious)

playhelminthes are considered…

acoelomate

coelom

fluid filled cavity that is completely closed within the body

dioecious

only produce eggs/sperm

how do most flatworms reproduce

mutual cross fertilization

in tricladida where are the eggs and the yolk produce (…,…)

ovaries, vitelline glands

eyespots

light gathering structures with no image resolving capacity

auricles

chemoreceptors

styles of flatworm motion (…,…)

things that help with motion

cilia, longitudinal muscle, circular muscle, deformable mesenchyme

what produces mucus

rhabdites

what is polycladida larva called

mullers larva

one distinctive feature of polyclads

ruffled pharynx

where is the egg and yolk produced in polycladida

ovaries

what type of pharynx do triclads have

cylindrical

what type of pharynx do rhabdocoela have

bulbous

where are the eggs and yolk produced in rhabdocoela and neodermata

ovaries, vitelline gland

neodermata epidermis

tegument

tegument does not have… and it is…

cilia, syncytial

monogenea

monogenetic flukes

trematoda

flukes

what is a distinctive feature of cestoda

GVC completely lost

scolex

attachment organ

reproductive organ in cestoda

proglottids

how are proglottids formed

budding posterior to the scolex

life cycle of trematoda

egg exposed to freshwater hatches to release miracidium (covered in cilia). Miracidium burrows into snail and develops into a sporocyte which feeds on snail’s tissues and produces many rediae (asexual reproduction). Rediae migrate to digestive glands and feed on glandular tissue. Each 1st gen rediae produces 2nd gen rediae which produce many cercaria. Cercaria burrow out of snail and attach to grass and encyst (form protective cyst walls), the metacercaria stage. When eaten by mammal intestine enzymes break down cyst walls and release immature flukes that burrow through intestine walls and move to liver. These young flukes eat liver tissue and attach to lining of bile ducts. Mutual cross fertilization occurs and fertilized eggs are released through bile duct. 

life cycle of cestoda

gravid proglottids periodically released from adult tapeworm into intestine and leave body along with feces. gradvid proglottids break apart and release eggs. Embryo develops into an onchosphere (with 6 hooks and a tough protective coating), this is eaten by a pig (intermediate host). In digestive tract oncosphere sheds protective coating and burrows into intestine wall and enters circulatory system and transported to skeletal muscle. Then develops into an invaginated cysticercus. When human eats pig that contains cysticercus it attaches to intestine wall (human is definitive host)