Flatworms, Nematodes and Arthropods Flashcards
Life cycle of beef tapeworm
- final/definitive host
- growth and dispersal of parasite in faeces
- ingestion by intermediate host (pig)
- becomes bladderworm in pig muscle, eaten by human in undercooked meat
- becomes adult tapeworm in humans
Cestoda scolex
method of attachment to intestinal crypts
Cestoda neck
generates new proglottids
Cestoda immature proglottids
immature reproductive organs
Cestoda mature proglottids
mature male and female organs
Cestoda gravid proglottids
Uterus with fertilised eggs which detach and pass out in host faeces
Cestoda strobila
Neck and proglottids which range in size from a few mm to >20m
Describe the class Trematoda
- flukes with flat, leaf like bodies
- adults live in vertebrate intestine
- attach to mucosal wall with suckers
- have a hermaphrodite reproductive system
- have 2 or more hosts
Phyla of Metazoa (5)
- Parazoa (Porifera)
- Eumetazoa (Radiata + Bilateria)
- Lophotrochozoa
- Ecdysozoa
- Deuterostomia
Structure (3) and characteristics (2) of Parazoa
- “Pore bearers”
- Body plan is a loose federation of cells in a gelatinous matrix
- Lack tissues and a true digestive system
- The simplest animals
- Filter feeders
Characteristics of Eumetazoa (1)
- separated into radial and bilateral based on body symmetry
Structure (5) and characteristics (2) of Cnidarians (radial eumetazoa)
- Stinging/nettle animals
- True tissues
- No brain
- Nerve + contractile filaments
- Gastrovascular cavity
- VENOMOUS PREDATORS
- Categorised into polyps or medusa
Examples of Polyps (2)
- Hydrozoa
- Anthozoa (corals and anemones)
Examples of Medusa (2)
- Scyphozoa (jellyfish)
- Cubozoa (box jellyfish)
Characteristics of Myxozoa (3)
- Cnidarians (Eumetazoa)
- Radially symmetric
- ALL parasitic
Benefits of bilateral symmetry
- Motor coordination (forward, direction motion)
- Allows for cephalization
Define cephalization, and what has it lead to (3)?
- Formation of a head region
- Sensory structures
- Brain development
- Mouth at cephalic end
Bilateria are ___blastic organisms
triplo (blastic)
Define triploblastic
Consisting of 3 germ layers
- ectoderm
- mesoderm
- endoderm
What are the advantages of being triploblastic? (2)
- specific tissues
- greater diversity and complexity
What tissues are in the ectoderm?
- skin, hair and nails
- mouth lining
- tooth enamel
- brain and nerves
What tissues are in the mesoderm?
- kidneys
- gonads
- circulatory system
- notochord
- muscles
- body cavity
What tissues are in the endoderm?
- GI tract lining
- respiratory tubes
- liver
- pancreas
Phyla of Lophotrochozoa (features of the mouth)
- Platyhelminthes
- Mollusca
- Annelida
- Acanthocephala
Structure (4) and characteristics (3) of Platyhelminthes (flatworms)
- no body cavity
- no circulatory system
- simple gut
- no anus
- have gaseous exchange across surface
- motile and predatory
- reproduce sexually or asexually
Groups of Platyhelminthes
- Turbellaria
- Monogenea
- Trematoda
- Cestoda
Characteristics of Turbellaria (4)
- In platyhelminthes, lophotrochozoa
- Parasites or commensals
- Mostly free living
- Ciliated epidermis
Example of Turbellaria
Planaria
- Are able to regenerate when cut
Characteristics of Monogenea
- obligate ectoparasites of fish
Structure (3) and characteristics (4) of Trematoda
- Flat, leaf like bodies
- Attach to mucosal wall with suckers
- Hermaphrodite reproductive system
- Obligatory endoparasites
- Flukes
- Adults live in vertebrate intestine
- 2 or more host
Example of Trematoda and life cycle
Fasciola Hepatica (Liver flukes)
- Affect a wide range of grazing animals
- Drink blood
- Pass in faeces via egg
- Larva enters snail and asexually reproduces
- Cercaria (2nd larva) exit snail, find a plant, animal eats plant
- Excysts in intestine, moves to liver where it is a sexually mature fluke
